• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.2
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• pp.179-184
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• 2017

Due to rapid development of infrared guided weapon, survivability of armored vehicle is severely threatened. Hence, reduction of susceptibility by lowering infrared signature level is essential to enhance survivability of the vehicle. For this purpose, numerical analysis is conducted to analyze time and spatial characteristics of infrared signature of the vehicle when surface emissivity changes in this study. The analysis shows that the emissivity which produces minimum contrast radiant intensity is significantly altered by time and detecting position. Based on the result, it is concluded that the controlled structures which have different emissivity should be adopted at different region of the vehicle to effectively decrease infrared signature level.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.4
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• pp.94-104
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• 2004

This study creates the LCP (Landscape Control Point) through the survey of spot sites for the quality of landscape assessment, which is based on an objective and departmentalized data base; the landscape assessment was achieved by production of weight value with the AHP (Analytic Hierarchy Process) technique, selection of requisites for the landscape assessment with the IVERSON method and visual area analysis with GIS (Geographic Information System). Futhermore, validity of the landscape assessment was verified by analysis of the correlation between physical amount and aesthetic amount. The purpose of this study is to suggest the basic essential data for landscape assessment and landscape planning by the characteristics of landscape based on verification of the suggested landscape assessment methods. The results of this study are summarized below. 1. In the adaptation of landscape assessment using GIS, the landscape assessment points of LCP 18, 17 and 16, which have more visible elements such as hill area, mountain area, and forest and farm land, were indicated to be higher than the others. In contrast, the landscape assessment points of LCP 13, 6 and 10, which have less visible elements, were relatively lower than the others. 2. In the visible preference measuring method, LCP 4, 14, and 16 showed high points of landscape assessment with 3.46, 3.4, and 3.18 each. With the more natural environments such as hill area, mountain area, and forest and farm land, higher results were shown. In contrast, LCP 7, 1, and 9 showed low points of landscape assessment with 2.24, 2.36, and 2.53 each. 3. In this study, a coefficient of 0.746 was gained by the analysis of correlation between the points of landscape assessment method and the points of visual preference from a slide show. This has 99 percent of probability in statistical data. 4. In conclusion, with the demonstration of the correlation between the landscape assessment method based on the AHP technique and the aesthetic amount (preference proportion), the practical use of landscape assessment can be demonstrated by the suggested landscape assessment method.

• Journal of Korean Society of Transportation
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• v.33 no.6
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• pp.520-530
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• 2015

This paper formulates the methodologies to estimate optimal congestion tolls from long-run and short-run perspectives and applies them to the highways of Seoul. An optimal long-run congestion toll is estimated with an optimal volume-capacity-ratio to minimize the total costs which consist of two components: road construction and maintenance costs and traveler costs. By contrast, an optimal short-run congestion toll is estimated with a supply-demand equilibrium which is determined by using a speed-flow function and a disaggregate modal choice model. The results of a long-run analysis for the Seobu urban expressway suggest the optimal volume-capacity-ratio of 1.35 and the optimal congestion toll of 503 Won per automobile kilometer. By contrast, those of a short-run analysis for the Mia-ro urban arterial suggest 1.31 and 420 Won, respectively. Although our results are to some degree dependent on the interest rate and time value assumed, one basic conclusion holds up: the congestions toll tested could generate substantial gains in social welfare if applied to Seoul.

• Journal of Korean Neurosurgical Society
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• v.62 no.5
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• pp.526-535
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• 2019

Objective : While the risk of aneurysmal rebleeding induced by catheter cerebral angiography is a serious concern and can delay angiography for a few hours after a subarachnoid hemorrhage (SAH), current angiographic technology and techniques have been much improved. Therefore, this study investigated the risk of aneurysmal rebleeding when using a recent angiographic technique immediately after SAH. Methods : Patients with acute SAH underwent immediate catheter angiography on admission. A four-vessel examination was conducted using a biplane digital subtraction angiography (DSA) system that applied a low injection rate and small volume of a diluted contrast, along with appropriate control of hypertension. Intra-angiographic aneurysmal rebleeding was diagnosed in cases of extravasation of the contrast medium during angiography or increased intracranial bleeding evident in flat-panel detector computed tomography scans. Results : In-hospital recurrent hemorrhages before definitive treatment to obliterate the ruptured aneurysm occurred in 11 of 266 patients (4.1%). Following a univariate analysis, a multivariate analysis using a logistic regression analysis revealed that modified Fisher grade 4 was a statistically significant risk factor for an in-hospital recurrent hemorrhage (p=0.032). Cerebral angiography after SAH was performed on 88 patients ${\leq}3$ hours, 74 patients between 3-6 hours, and 104 patients >6 hours. None of the time intervals showed any cases of intra-angiographic rebleeding. Moreover, even though the DSA ${\leq}3$ hours group included more patients with a poor clinical grade and modified Fisher grade 4, no case of aneurysmal rebleeding occurred during erebral angiography. Conclusion : Despite the high risk of aneurysmal rebleeding within a few hours after SAH, emergency cerebral angiography after SAH can be acceptable without increasing the risk of intra-angiographic rebleeding when using current angiographic techniques and equipment.

• Journal of the Korean Society of Food Culture
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• v.35 no.6
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• pp.538-552
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• 2020

Tis study was an attempt to systematically analyze the characteristics of modern Korean food styling using the menu image photos of the Michelin Guide Seoul 2020 restaurants. The first sampling was conducted on the 27th of March 2020 and the second on the 27th of October 2020. A collection of images on the web and 442 photographic cases obtained by a search through theoretical background literature and research papers were studied by a qualitative analysis method. First, the food styling contents were analyzed and based on that, the food styling characteristics of the menus of 11 restaurants in Korea including the contemporary restaurants were considered. The analysis revealed several aspects of Korean food styling. First, food styling appeared to have three major characteristics: color, shape, and container styling. Color styling was further subdivided into single color/similar color, color contrast, source type, and accent color type. The shape/formative styling was classified into figure type, shape type, accessory type, and garnish type, and container styling was categorized as container color type, container shape type, and container material type. Second, the modern Korean food color styling characteristics of Michelin restaurants were categorized in the order of monochromatic/similar type, sauce type, accent color type, and color contrast. In the formative styling category, it was categorized in the order of shape type, small piece type, garnish/garnish type, and figure type. In container styling, container material type and formative type accounted for the major portion of the category. The food styling characteristics of the modern Korean menu were systematized and image examples were presented visually. Please use it as food styling educational material or personal food styling skill.

• Journal of Fashion Business
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• v.25 no.5
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• pp.1-24
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• 2021

This study aimed to explore the fashion design and style features, and differences in BLACKPINK, TWICE, and Red Velvet girl groups. A total of 469 fashion photos (132 BLACKPINK, 217 TWICE, 120 Red Velvet) focusing on 23 title songs (7 BLACKPINK, 9 TWICE, 7 Red Velvet) were collected. Photo classification work was carried out in accordance with the design analysis criteria and the results were derived by combining statistical analysis and content analysis. BLACKPINK's fashion design characteristics showed a lot of complex colors, shade tone, pure tone, contrast color coordination, stylistic pattern, slit, patchwork, checklist method, sexy and avant-garde images. TWICE's fashion design characteristics included warm color, complex color, tint tone, monotone, contrast color coordination, tone-on-tone, geometric & stylistic patterns, cotton, silk, a combination of the same material, frill, beads, ribbon decoration, blouse, skirt, and many romantic and ethnic images. Red Velvet's fashion design characteristics were a cold color, moderate tone, monotone, cotton, velvet, geometric pattern, zipper, sequins, T-shirt, pants, tie, belt, and many retro and active images. The fashion styles of BLACKPINK, TWICE, and Red Velvet were as follows. BLACKPINK was divided into sexy avant-garde, sexy active, sexy romantic styles. TWICE was divided into romantic active, romantic classical, and romantic ethnic styles. Red Velvet was divided into retro active, retro sexy, and retro avant-garde styles.

• Journal of Korea Trade
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• v.27 no.5
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• pp.167-198
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• 2023

Purpose - This paper aims to compare and analyze the co-movements and information spillover effects between the international commodity futures markets and the South Korean stock markets during the COVID-19 and the 2008 financial crises. Design/methodology - The DCC-GARCH model is used in the co-movements analysis. In contrast, the BEKK-GARCH model is used to evaluate information spillover effects. The statistical data used is from January 1, 2005, to December 31, 2022. It comprises the Korea Composite Stock Price Index data and daily international commodity futures prices of natural gas, West Texas Intermediate crude oil, gold, silver, copper, nickel, soybean, and wheat. Findings - The results of the co-movement analysis were as follows: First, it was shown that the co-movements between the international commodity futures markets and the South Korean stock markets were temporarily strengthened when the COVID-19 and 2008 financial crises occurred. Second, the South Korean stock markets were shown to have high correlations with the copper, nickel, and crude oil futures markets. The results of the information spillover effects analysis are as follows: First, before the 2008 financial crisis, four commodity futures markets (natural gas, gold, copper, and wheat) were shown to be in two-way leading relationships with the South Korean stock markets. In contrast, seven commodity futures markets, except for the natural gas futures market, were shown to be in two-way leading relationships with the South Korean stock markets after the financial crisis. Second, before the COVID-19 crisis, most international commodity futures markets, excluding natural gas and crude oil future markets, were shown to have led the South Korean stock markets in one direction. Third, it was revealed that after the COVID-19 crisis, the connections between the South Korean stock markets and the international commodity futures markets, except for natural gas, crude oil, and gold, were completely severed. Originality/value - Useful information for portfolio strategy establishment can be provided to investors through the results of this study. In addition, it is judged that financial policy authorities can utilize the results as data for efficient regulation of the financial market and policy establishment.

• Korean Journal of Radiology
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• v.22 no.5
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• pp.735-741
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• 2021

Objective: To evaluate circularity as a quantitative shape factor of small renal tumor on computed tomography (CT) in differentiating fat-poor angiomyolipoma (AML) from renal cell carcinoma (RCC). Materials and Methods: In 257 consecutive patients, 257 pathologically confirmed renal tumors (either AML or RCC less than 4 cm), which did not include visible fat on unenhanced CT, were retrospectively evaluated. A radiologist drew the tumor margin to measure the perimeter and area in all the contrast-enhanced axial CT images. In each image, a quantitative shape factor, circularity, was calculated using the following equation: 4 x π x (area ÷ perimeter²). The median circularity (circularity index) was adopted as a representative value in each tumor. The circularity index was compared between fat-poor AML and RCC, and the receiver operating characteristic (ROC) curve analysis was performed. Univariable and multivariable binary logistic regression analysis was performed to determine the independent predictor of fat-poor AML. Results: Of the 257 tumors, 26 were AMLs and 231 were RCCs (184 clear cell RCCs, 25 papillary RCCs, and 22 chromophobe RCCs). The mean circularity index of AML was significantly lower than that of RCC (0.86 ± 0.04 vs. 0.93 ± 0.02, p < 0.001). The mean circularity index was not different between the subtypes of RCCs (0.93 ± 0.02, 0.92 ± 0.02, and 0.92 ± 0.02 for clear cell, papillary, and chromophobe RCCs, respectively, p = 0.210). The area under the ROC curve of circularity index was 0.924 for differentiating fat-poor AML from RCC. The sensitivity and specificity were 88.5% and 90.9%, respectively (cut-off, 0.90). Lower circularity index (≤ 0.9) was an independent predictor (odds ratio, 41.0; p < 0.001) for predicting fat-poor AML on multivariable logistic regression analysis. Conclusion: Circularity is a useful quantitative shape factor of small renal tumor for differentiating fat-poor AML from RCC.

• Korean Journal of Radiology
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• v.24 no.4
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• pp.349-361
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• 2023

Objective: To quantitatively assess the pulmonary vasculature using non-contrast computed tomography (CT) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) pre- and post-treatment and correlate CT-based parameters with right heart catheterization (RHC) hemodynamic and clinical parameters. Materials and Methods: A total of 30 patients with CTEPH (mean age, 57.9 years; 53% female) who received multimodal treatment, including riociguat for ≥ 16 weeks with or without balloon pulmonary angioplasty and underwent both non-contrast CT for pulmonary vasculature analysis and RHC pre- and post-treatment were included. The radiographic analysis included subpleural perfusion parameters, including blood volume in small vessels with a cross-sectional area ≤ 5 mm² (BV5) and total blood vessel volume (TBV) in the lungs. The RHC parameters included mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac index (CI). Clinical parameters included the World Health Organization (WHO) functional class and 6-minute walking distance (6MWD). Results: The number, area, and density of the subpleural small vessels increased after treatment by 35.7% (P < 0.001), 13.3% (P = 0.028), and 39.3% (P < 0.001), respectively. The blood volume shifted from larger to smaller vessels, as indicated by an 11.3% increase in the BV5/TBV ratio (P = 0.042). The BV5/TBV ratio was negatively correlated with PVR (r = -0.26; P = 0.035) and positively correlated with CI (r = 0.33; P = 0.009). The percent change across treatment in the BV5/TBV ratio correlated with the percent change in mPAP (r = -0.56; P = 0.001), PVR (r = -0.64; P < 0.001), and CI (r = 0.28; P = 0.049). Furthermore, the BV5/TBV ratio was inversely associated with the WHO functional classes I-IV (P = 0.004) and positively associated with 6MWD (P = 0.013). Conclusion: Non-contrast CT measures could quantitatively assess changes in the pulmonary vasculature in response to treatment and were correlated with hemodynamic and clinical parameters.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.229-238
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• 2000

Simulation analysis for an auto body manufacturing system has been performed in this study. The major goal is to figure out the condition yielding the production rate, 70 per hour. It is, however, very difficult to maintain this rate due to inherent system factors such as machine failure rates, machine repair rates, number of carriers between manufacturing lines(shops), carrier speed etc. We first carefully examined the system and developed a simulation model using ARENA. We then applied statistical experimental design concepts for performance analysis. Our results indicate that the buffer size of 30 and quick repair of failed robots are required for the desired production rate. Other factors, on the other hand, are seen to have minor effects on the throughput. The approach taken in this study and the results obtained may provide a practical guideline for performance analysis and thus be applied without trepidation for similar cases.