• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.3
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• pp.13-24
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• 2019

Adolescence is a transitional stage of physical development which occurs during the period from puberty to adulthood. Going through this period, various parts of an adolescent's body grow at different rates, leading to different body shapes and proportions when compared to adults. Therefore, this study aimed to investigate the body sizes and shapes of junior high school boys from ages 13-15 based on body measurement items that are used as the basis for school uniform designs including jackets, shirts, and pants. For this, the study sought the basic data needed to develop body shapes and school uniform patterns for junior high school boys using the data from the 6th Size Korea Survey (2010). Specifically, it provided basic data for the development of school uniform patterns that fit well through the classification of bodies into particular types. After extracting body shape componen a cluster analysis using ANOVA was performed. According to the factor analysis conducted to determine body shape components, 5 factors were obtained as follows: Factor 1: bulk and horizontal size, Factor 2: body height and length, Factor 3: shoulder shape and length, Factor 4: characteristics of horizontal size, Factor 5: shape of the upper body with a variance of 82.62%. To classify junior high school boys' body shape was determined using various characteristics, and a cluster analysis was performed with the variables obtained by the factor analysis. For this, body shapes were classified into 3 different types: Type 1 accounted for 33.4%, with a total of 463 subjects. This type was a tall, long body individual with the smallest bulk and size. Type 2 accounted for 22.7%, with a total of 315 subjects. This type was large in bulk and horizontal size, but the lowest in height and length. Type 3 accounted for 43.9%, with a total of 610 subjects. This type was close to average in terms of horizontal size, length, and height. To develop well-fitting school uniforms for junior high school students, there should be further studies on changes in body shape and their associated causes. The study results will be available as basic data for comparing branded school uniform patterns for junior high school boys and developing school uniform patterns based on body shape, using 3D virtual clothing simulations.

• Composites Research
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• v.32 no.1
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• pp.65-70
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• 2019

The aircraft composites wing parts are usually integrated with adhesive or fastener. These laminated composites have weak interlaminar strength, which can lead to delamination. In order to compensate the disadvantages of laminated composites, it is possible to improve the strength, durability, shock and fatigue resistance by reinforcing the fiber in the thickness direction. In addition, using a single structure near-net-shape saves the manufacturing time and the number of fasteners, thus can reduce the overall cost of the composite parts. In this study, compression test, tensile test and open-hole tensile test are carried out for three structural architecture of 3D (three-dimensional) textile preforms: orthogonal(ORT), layer-to-layer(LTL) and through-the-thickness(TTT) patterns. Among these, the orthogonal textile composite shows the highest Young's modulus and strength in tensile and compression. The notch sensitivity of the orthogonal textile composite was the smallest as compared with UD (unidirectional) and 2D (two-dimensional) fabric laminates.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.1-8
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• 2019

Identifying behavioral errors of seafarers that have led to marine accidents is a basis for research into prevention or mitigation of marine accidents. The purpose of this study is to estimate the optimal probability distribution function needed to model behavioral errors of crew members into three behaviors (i.e., Skill-, Rule-, Knowledge-based). Through use of behavioral data obtained from previous accidents, we estimated the optimal probability distribution function for the three behavioral errors and verified the significance between the probability values derived from the probability distribution function. Maximum Likelihood Estimation (MLE) was applied to the probability distribution function estimation and variance analysis (ANOVA) used for the significance test. The obtained experimental results show that the probability distribution function with the smallest error can be estimated for each of the three behavioral errors for eight types of marine accidents. The statistical significance of the three behavioral errors for eight types of marine accidents calculated using the probability distribution function was observed. In addition, behavioral errors were also found to significantly affect marine accidents. The results of this study can be applied to predicting marine accidents caused by behavioral errors.

• Fire Science and Engineering
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• v.33 no.1
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• pp.30-38
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• 2019

Mixing characteristics and backdraft dynamics were investigated using large eddy simulation for compartments initially filled with methane fuel. Four different opening geometries, i.e. conventional door opening case (Door) and the cases where horizontal door was implemented on the upper ($Slot_U$), middle ($Slot_M$) and lower part ($Slot_L$) of side wall, were considered in the simulations. For cases without ignition, the amounts of inflow oxygen and outflow fuel from the compartment opening were, from largest to smallest, Door > $Slot_U$ ~ $Slot_M$ > $Slot_L$. However, the fuel and oxygen were the best mixed for the $Slot_U$ case while the fuel and oxygen were not well mixed and in relatively separated two layers for the $Slot_L$ case. The global equivalence ratio defined by the amounts of fuel and oxygen in the compartment was not correlated reasonably with the peak pressure of backdraft. The peak pressure during backdraft was the highest for the $Slot_U$ case, a well mixed condition of fuel and air, and backdraft was not found for the $Slot_L$ where the pressure rise was not so high due to the mixing status. The peak pressures for the Door and $Slot_M$ cases were in between Door and $Slot_L$ cases. The peak pressure during backdraft was well correlated with the total amount of heat release until the instance of backdraft occurrence.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.2
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• pp.297-302
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• 2019

In this study, we deposited ITO thin films on buffer layer of $Nb_2O_5(8nm)/SiO_2(45nm)$ using DC magnetron sputtering method and investigated its electrical and optical properties with various DC powers(100~400 W). The surface of the ITO thin film was observed by AFM. All thin films had defected free surface such as pinholes and cracks. The thin film deposited at DC power of 200 W exhibited the smallest surface roughness of 1.431nm. As a result of electrical and optical measurements, the ITO thin film deposited at DC power of 200 W which showed the lowest resistivity of $3.03{\times}10^{-4}{\Omega}-cm$. The average transmittance in the visible light region(400 to 800 nm) and the transmittance at the wavelength of 550nm were found to be 85.8% and 87.1%, respectively. The chromaticity(b*) was also a relatively good value as 2.13. The figure of merit obtained from the sheet resistance of the ITO thin film, the average transmittance in the visible light region and the transmittance at the wavelength of 550nm were the best values of $2.50{\times}10^{-3}{\Omega}^{-1}$ and $2.90{\times}10^{-3}{\Omega}^{-1}$ at a DC power of 200W, respectively.

• Food Engineering Progress
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• v.21 no.4
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• pp.326-331
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• 2017

A cultivar (Malus domestica cv. Fuji) of apple was selected to make apple peel (AP) powder by three different powdering methods. Frozen AP was thawed and subsequently was dried or ground without drying. After AP was dried by hot-air drying at $60^{\circ}C$ or freeze-drying, the dried AP was ground using a conventional blender. Separately, the thawed AP was powered by using a cryogenic micro grinding technology (CMGT). The ground AP and three types of AP powder were extracted using deionized water, 20, 40, 60, 80, or 100% methanol, followed by vacuum evaporation. The total phenolics contents (TPC), total flavonoids contents (TFC), DPPH, and ABTS radical scavenging capacities of each extract were compared to determine an efficient powdering method. Lyophilized AP powder extract using 60% methanol showed the highest TPC and DPPH radical scavenging capacity. In contrast, 60% methanol extract of the powder by CMGT, resulting in the smallest particle, exhibited the highest TFC and ABTS radical scavenging capacity. This study suggests that the extraction yield of bioactive compounds from AP may be varied according to different powdering methods and that a new powdering process such as CMGT may be applicable to develop functional foods efficiently.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.91-97
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• 2021

By introducing an organic interlayer on the Parylene C dielectric surface, the electrical device performances and the operating stabilities of organic field-effect transistors (OFETs) were improved. To achieve this goal, hexamethyldisilazane (HMDS) and octadecyltrichlorosilane (ODTS), as the organic interlayer materials, were used to control the surface energy of the Parylene C dielectrics. For the bare case used with the pristine Parylene C dielectrics, the field-effect mobility (μ_FET) and threshold voltage (V_th) of dinaphtho[2,3-b:2',3'-f ]thieno[3,2-b]- thiophene (DNTT) FET devices were measured at 0.12 cm²V^-1s^-1 and - 5.23 V, respectively. On the other hand, the OFET devices with HMDS- and ODTS-modified cases showed the improved μ_FET values of 0.32 and 0.34 cm²V^-1s^-1, respectively. More important point is that the μ_FET and V_th of the DNTT FET device with the ODTS-modified Parylene C dielectric presented the smallest changes during a repeated measurement of 1000 times, implying that it has the most stable operating stability. The results could be meaned that the organic interlayer, especially ODTS, effectively covers the Parylene C dielectric surface with alkyl chains and reduces the charge trapping at the interface region between active layer and dielectric, thereby improving the electrical operating stability.

• Journal of Korea Water Resources Association
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• v.54 no.5
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• pp.301-309
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• 2021

In this study, we tried to improve the performance of the existing U-net-based deep learning rainfall prediction model, which can weaken the meaning of time series order. For this, ConvLSTM2D U-Net structure model considering temporal consistency of data was applied, and we evaluated accuracy of the ConvLSTM2D U-Net model using a RainNet model and an extrapolation-based advection model. In addition, we tried to improve the uncertainty in the model training process by performing learning not only with a single model but also with 10 ensemble models. The trained neural network rainfall prediction model was optimized to generate 10-minute advance prediction data using four consecutive data of the past 30 minutes from the present. The results of deep learning rainfall prediction models are difficult to identify schematically distinct differences, but with ConvLSTM2D U-Net, the magnitude of the prediction error is the smallest and the location of rainfall is relatively accurate. In particular, the ensemble ConvLSTM2D U-Net showed high CSI, low MAE, and a narrow error range, and predicted rainfall more accurately and stable prediction performance than other models. However, the prediction performance for a specific point was very low compared to the prediction performance for the entire area, and the deep learning rainfall prediction model also had limitations. Through this study, it was confirmed that the ConvLSTM2D U-Net neural network structure to account for the change of time could increase the prediction accuracy, but there is still a limitation of the convolution deep neural network model due to spatial smoothing in the strong rainfall region or detailed rainfall prediction.

• Phonetics and Speech Sciences
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• v.12 no.4
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• pp.1-8
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• 2020

Traditionally it has been understood that the aspirated and lenis stops in Seoul Korean are distinguished primarily by voice onset time (VOT) and secondarily by other cues such as the fundamental frequency (F0) of the following vowel. However, recent studies on stop production have shown that the aspirated and lenis stops are currently merging in VOT and that they are now differentiated primarily by F0. In the present study, we examined whether the currently reported change in the production domain would be also found in the perception domain. To this end, an auditory identification task was conducted using speech materials of varying VOT and F0 values with young and older male and female Seoul listeners. Results revealed that all listener groups used both VOT and F0 to distinguish the lenis vs. aspirated stops but they used the F0 cue more reliably than the VOT cue in discriminating the stop contrast. The effects of gender and age were found only in the VOT cue (i.e., not in the F0 cue), with the greatest VOT cue weight in older males and the smallest in young females, which is in line with recent production studies.

• Journal of Environmental Health Sciences
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• v.46 no.6
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• pp.719-725
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• 2020

Objectives: With the growth of national interest in fine particulate matter, many complaints about pollutants emitted from air pollution emitting facilities have arisen in recent years. In particular, it is thought that a large volume of particulate pollutants are discharged from workplaces that use Solid Refuse Fuel (SRF). Therefore, particulate contaminants generated from SRF were measured and analyzed in this study in terms of respective particle sizes. Methods: In this study, particulate matter in exhaust gas was measured by applying US EPA method 201a using a cyclone. This method measures Filterable Particulate Matter (FPM), and does not consider the Condensable Particulate Matter (CPM) that forms particles in the atmosphere after being discharged as a gas in the exhaust gas. Results: The mass concentration of Total Suspended Particles (TSP) in the four SRF-using facilities was 1.16 to 11.21 mg/Sm3, indicating a very large concentration deviation of about 10 times. When the fuel input method was the continuous injection type, particulate matter larger than 10 ㎛ diameter showed the highest particle size fraction, followed by particulate matter smaller than 10 ㎛ and larger than 2.5 ㎛, and particulate matter of 2.5 ㎛ or less. Contrary to the continuous injection type, the batch injection type had the smallest particle size fraction of particulate matter larger than 10 ㎛. The overall particulate matter decreased as the operating load factor decreased from 100% to 60% at the batch input type D plant. In addition, as incomplete combustion significantly decreased, the particle size fraction also changed significantly. Both TSP and heavy metals (six items) satisfied the emissions standards. The measured value of the emission factor was 38-99% smaller than the existing emissions factor. Conclusions: In the batch injection facility, the particulate matter decreased as the operating load factor decreased, as did the particle size fraction of the particulate matter. These results will help the selection of effective methods such as reducing the operating load factor instead of adjusting the operating time during emergency reduction measures.