• Journal of Digital Convergence
• /
• v.17 no.9
• /
• pp.39-46
• /
• 2019

This study started with the question of whether the percentage of non-aeronautical revenues at Incheon airport was extremely high when compared with other international airports. Although aeronautical revenues for the airport based on the traditional business model have the limits to grow due to various regulations, stakeholders concerned about improving the competitiveness recently have been interested in increasing non-aeronautical revenues. This study deals with the effect of non-aeronautical revenues at international airports on airport charges as the extent of airport privatization get stronger. To examine hypotheses, we collected international data from trustful sources. Finally, we conducted an empirical analysis of 178 airports worldwide. As a result, the higher the percentage of non-aeronautical revenues at international airports, the lower the airport charges were. Besides, the private equity ratio positively moderated the relationship between the percentage of non-aeronautical revenues and airport charges. Privatization of airports may offset the effects of reduced airport charges through increased commercial activity. Graphical display for moderation effect is offered to facilitate comprehension.

• Steel and Composite Structures
• /
• v.31 no.1
• /
• pp.13-25
• /
• 2019

Reactive powder concrete (RPC) is a type of ultra-high strength concrete that has a relatively high brittleness. However, its ductility can be improved by confinement, and the use of RPC in composite RPC filled steel tube columns has become an important subject of research in recent years. This paper aims to present an experimental study of axial capacity calculation of RPC filled circular steel tube columns. Twenty short columns under axial compression were tested and information on their failure patterns, deformation performance, confinement mechanism and load capacity were presented. The effects of load conditions, diameter-thickness ratio and compressive strength of RPC on the axial behavior were further discussed. The experimental results show that: (1) specimens display drum-shaped failure or shear failure respectively with different confinement coefficients, and the load capacity of most specimens increases after the peak load; (2) the steel tube only provides lateral confinement in the elastic-plastic stage for fully loaded specimens, while the confinement effect from steel tube initials at the set of loading for partially loaded specimens; (3) confinement increases the load capacity of specimens by 3% to 38%, and this increase is more pronounced as the confinement coefficient becomes larger; (4) the residual capacity-to-ultimate capacity ratio is larger than 0.75 for test specimens, thus identifying the composite columns have good ductility. The working mechanism and force model of the composite columns were analyzed, and based on the twin-shear unified strength theory, calculation methods of axial capacity for columns with two load conditions were established.

• Journal of Digital Convergence
• /
• v.19 no.6
• /
• pp.251-258
• /
• 2021

In this paper, we proposed an encoder-decoder model utilizing residual learning to improve the accuracy of the U-Net-based semantic segmentation method. U-Net is a deep learning-based semantic segmentation method and is mainly used in applications such as autonomous vehicles and medical image analysis. The conventional U-Net occurs loss in feature compression process due to the shallow structure of the encoder. The loss of features causes a lack of context information necessary for classifying objects and has a problem of reducing segmentation accuracy. To improve this, The proposed method efficiently extracted context information through an encoder using residual learning, which is effective in preventing feature loss and gradient vanishing problems in the conventional U-Net. Furthermore, we reduced down-sampling operations in the encoder to reduce the loss of spatial information included in the feature maps. The proposed method showed an improved segmentation result of about 12% compared to the conventional U-Net in the Cityscapes dataset experiment.

• The Journal of the Korea Contents Association
• /
• v.22 no.9
• /
• pp.147-155
• /
• 2022

This article analyzed the new changes Hong Kong director Lin Chaoxian has brought to theme films of Mainland China and the factors affecting these changes. The objects of the analysis are Lin Chaoxian's films (2016), (2018), and (2020). Compared with Mainland China directors suffering from heavy political burden, Dante Lam directed theme films based on the model from commercial films and adopted lots of elements from Hong Kong films. There, the ideology expression in these theme films was no longer rigid, but a diversified value embodiment resonating with the audience. At the same time, these theme films achieved higher commercial value, in which the stereotyped and unrealistic hero images were replaced by realistic and compound characters, and the display of cool or violent action scenes contributed to lots of visual feasts. All the changes were influenced by the audience preferences and the development of private enterprises in Mainland China.

• Journal of Broadcast Engineering
• /
• v.27 no.5
• /
• pp.808-811
• /
• 2022

Display under strong ambient lighting is perceived darker than it really is. Existing techniques for solving the problem in terms of software show limitations in that image enhancement techniques are applied regardless of ambient lighting or chrominance is not improved compared to luminance. Therefore, this paper proposes a visibility enhancement algorithm using deep learning to adaptively respond to ambient lighting values and an equation to restore optimal chrominance for luminance. The algorithm receives an ambient lighting value with the input image, and then applies a deep learning model and chrominance restoration equation to generate an image to minimize the difference between the degradation modeling of enhanced image and the input image. Qualitative evaluation proves that the algorithm shows excellent performance in improving visibility under strong ambient lighting through comparison of images applied with degradation modeling.

• Fashion & Textile Research Journal
• /
• v.24 no.1
• /
• pp.117-126
• /
• 2022

This study aims to analyze the sizing information of women's ready-to-wear pants as indicated on online retail websites and to suggest better sizing communication that can assist customers in making successful apparel size selections. We gathered size specifications and size reference information for basic straight pants from 34 online apparel retail websites. Although the Korean standard recommends labeling the body dimension-based sizing code and specification, most websites preferred to use various types of sizing codes. Body measurements were only used by a few websites, and garment dimension descriptions were the most common method to indicate product size. Many websites provided size reference information through customer review boards and fit model images, however, there was insufficient body size information to allow customers to infer the fit of their body type. When using the size guidance tools, the major data input points were stature and weight measurements. However, the waist measurements of pants sizes guided only by stature and weight values revealed inconsistent ease allowance for corresponding body size populations, especially in the overweight group. Based on our findings, we propose a more effective method of communicating the size information of pants online. We expect that this will contribute to the efficiency of online apparel product display and build a better shopping environment that satisfies both sellers and consumers.

• The Korean Journal of Physiology and Pharmacology
• /
• v.26 no.5
• /
• pp.347-355
• /
• 2022

Abdominal aortic aneurysm (AAA) is a life-threatening disorder worldwide. Fibroblast growth factor 21 (FGF21) was shown to display a high level in the plasma of patients with AAA; however, its detailed functions underlying AAA pathogenesis are unclear. An in vitro AAA model was established in human aortic vascular smooth muscle cells (HASMCs) by angiotensin II (Ang-II) stimulation. Cell counting kit-8, wound healing, and Transwell assays were utilized for measuring cell proliferation and migration. RT-qPCR was used for detecting mRNA expression of FGF21 and activating transcription factor 4 (ATF4). Western blotting was utilized for assessing protein levels of FGF21, ATF4, and markers for the contractile phenotype of HASMCs. ChIP and luciferase reporter assays were implemented for identifying the binding relation between AFT4 and FGF21 promoters. FGF21 and ATF4 were both upregulated in Ang-II-treated HASMCs. Knocking down FGF21 attenuated Ang-II-induced proliferation, migration, and phenotype switch of HASMCs. ATF4 activated FGF21 transcription by binding to its promoter. FGF21 overexpression reversed AFT4 silencing-mediated inhibition of cell proliferation, migration, and phenotype switch. ATF4 transcriptionally upregulates FGF21 to promote the proliferation, migration, and phenotype switch of Ang-II-treated HASMCs.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.369-375
• /
• 2004

Gas turbine engine simulation in terms of transient, steady state performance and operational characteristics is complex work at the various engineering functions of aero engine manufacturers. Especially, efficiency of control system design and development in terms of cost, development period and technical relevance implies controlling diverse simulation and identification activities. The previous engine simulation has been accomplished within a limited analysis area such as fan, compressor, combustor, turbine, controller, etc. and this has resulted in improper engine performance and control characteristics because of limited interaction between analysis areas. In this paper, we propose a new simulation methodology for gas turbine engine performance analysis as well as its digital controller to solve difficulties as mentioned above. The novel method has particularities of (ⅰ) resulting in the integrated control simulation using almost every component/module analysis, (ⅱ) providing automated math model generation process of engine itself, various engine subsystems and control compensators/regulators, (ⅲ) presenting total sophisticated output results and easy understandable graphic display for a final user. We call this simulation system GT3GS (Gas Turbine 3D Graphic Simulator). GT3GS was built on both software and hardware technology for total simulation capable of high calculation flexibility as well as interface with real engine controller. All components in the simulator were implemented using COTS (Commercial Off the Shelf) modules. In addition, described here includes GT3GS main features and future works for better gas turbine engine simulation.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.33 no.4
• /
• pp.419-426
• /
• 2023

Objectives: This study aims to develop an Occupational Safety and Health (OSH) guide for the safe cleaning of contaminated machinery, equipment, and parts used in the electronics manufacturing process. Methods: A literature review, field investigations, and discussions were conducted. An initial draft of an OSH guide was developed and reviewed by experts with significant experience in maintenance work in the electronics manufacturing process in order to refine the guide. Results: Workers involved in cleaning processes with chemicals, solvents, and abrasive blasting can face exposure to a wide range of chemicals, abrasives, and noise. Identifying potential risks associated with each cleaning technique was an essential first step toward enhancing safety measures. The OSH guide comprises approximately eleven to twelve sections spanning 20-25 pages. It includes engineering and administrative protocols systematically organized to address the necessary actions before, during, and after cleaning tasks, depending on the technique. It is recommended that airline respirator masks be used in conjunction with an air purification system to ensure adherence to air quality standard "D" for atmosphere level. The use of an oil-free air compressor is advised, preferably a stationary model that does not rely on fuel sources like diesel. Conclusions: This OSH guide is designed to protect workers involved in maintenance activity in the electronics industry and aligns with global standards, such as those from the International Organization for Standardization (ISO) and Semiconductor Equipment and Material International, ensuring a higher level of safety and compliance.

• Journal of Veterinary Science
• /
• v.24 no.5
• /
• pp.49.1-49.15
• /
• 2023

Background: Hystricomorpha rodents display a similar placentation model to humans. The present study was carried out considering the scarcity of information concerning the placental development in agouti. Objective: Describe the microscopy of the placenta, subplacenta and yolk sac of agoutis in early pregnancy and report on the inversion of the yolk sac. Methods: Fifteen females between the 14^th-32^nd day of gestation were used following euthanasia. Gestational buttons were collected, fixed, processed, stained to optical microscopy or immunohistochemistry. Results: Chorioallantoic placenta (CP) ranged from conical to a half-sphere, as follows: from the 14^th to 17^th day, the CP displays an inverted "V" shape, predominantly formed by cytotrophoblasts; from 20 to 22 days, formed almost entirely by cytotrophoblasts; at 28 days, a half sphere, with distinct lobes and interlobular area, numerous maternal gaps delimited by syncytiotrophoblasts and trophoblast giant cells; at 32 days, globose and undergoing the maturation process. Subplacenta, located between decidua and CP, initially presents septa consisting of simple columnar epithelium and after 17 days, comprising stratified epithelium. Visceral yolk sac (VYS) is attached to two CP projections between 14 and 17 days, formed by a simple cubic epithelium and inverted. Between 20 and 22 days, the epithelium displays apical villous projections with cytoplasmic vacuoles and a vascularized mesoderm. After the 24^th day, the VYS near the placenta is pleated, very vascularized and villous, with decreased villi sizes further away from the placenta. Conclusion: The agouti CP displays similar characteristics to other hystricomorpha, including placenta lobulation, a subplacenta and an inverted vitelline placenta.