• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4146-4158
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• 2022

Ultra-high performance concrete (UHPC) has been widely utilized in military and civil protective structures to resist intensive loadings attributed to its excellent properties, e.g., high tensile/compressive strength, high dynamic toughness and impact resistance. At present, aiming to improve the defects of the traditional vertical concrete cask (VCC), i.e., the external storage facility of spent fuel, with normal strength concrete (NSC) shield, e.g., heavy weight and difficult to fabricate/transform, the feasibility of UHPC applied in the shield of VCC is numerically examined considering its high radiation and corrosion resistance. Firstly, the finite element (FE) analyses approach and material model parameters of NSC and UHPC are verified based on the 1/3 scaled VCC tip-over test and drop hammer test on UHPC members, respectively. Then, the refined FE model of prototypical VCC is established and utilized to examine its dynamic behaviors and damage distribution in accidental tip-over and end-drop events, in which the various influential factors, e.g., UHPC shield thickness, concrete ground thickness, and sealing methods of steel container are considered. In conclusion, by quantitatively evaluating the safety of VCC in terms of the shield damage and vibrations, it is found that adopting the 300 mm-thick UHPC shield instead of the conventional 650 mm-thick NSC shield can reduce about 1/3 of the total weight of VCC, i.e., about 50 t, and 37% floor space, as well as guarantee the structural integrity of VCC during the accidental drop simultaneously. Besides, based on the parametric analyses, the thickness of concrete ground in the VCC storage site is recommended as less than 500 mm, and the welded connection is recommended for the sealing method of steel containers.

• International journal of advanced smart convergence
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• v.12 no.4
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• pp.300-305
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• 2023

This thesis is a study of content development utilizing media outlets to date through digital humans. The trend of global content is that the video content industry, including the character business, is growing. Lil Michela, who was selected as one of the 25 most influential people on the Internet by Time magazine in 2018, Nasua, who appeared in a SK Telecom commercial, and Rosie, who appeared in a Shinhan Bank commercial, are representative. Digital humans, which are driving new content, are computer-generated human characters with various characteristics and are referred to as virtual humans, metahumans, and cyber humans. With the rise of the metaverse after COVID-19, digital humans are being utilized in various forms such as media and marketing as an element of visual content. In the form of media, we can see that the boundaries between the offline and digital worlds are converging, and in the form of marketing, we can see that digital humans connect consumers and products more naturally. In the form of interaction, it is possible to achieve two-way communication through various methods of operation, and through these factors, it is possible to go beyond behavioral communication in the form of memorialization to emotional communication through AI technology. What can be seen through these processes is that through the currently developing digital human production methods and AI functions, not only experts but also non-experts can create quality contents, and new directions of contents will appear, and contents that can provide immediate feedback by bringing consumers and creators closer together have been studied.

• Journal of Korean Society of Transportation
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• v.21 no.1
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• pp.127-136
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• 2003

Road safety is defined under the minimum design standard and design examination process is consisted of the standard according to current road design. However, road safety in practical way is correlative to not only all element of roads but also road shape, such as, between straight line and curved line and between curved lines. Also. it is related to alignments such as horizontal alignment and vertical alignment, and cross section. That is, the practical road design should be examined in both sides of 3 dimension and consecutiveness (consistency) as the actual road is a 3 - dimensional successive object. The paper presents a concept for acceleration to evaluate consistency of road considering actual road shape on 3-dimension. Acceleration of vehicle is influential to road consistency based on running state of vehicles and state of drivers. The magnitude of acceleration. especially, is a quite influential element to drivers. Based on above, the acceleration on each point on 3-D road can be calculated and then displacement can be done. Computation of acceleration means total calculation on each axis. Speed profile refers to “Development of a safety evaluation model for highway horizontal alignment based on running speed(Jeong, Jun-Hwa, 2001)” and then acceleration can be calculated by using the speed pronto. According to literature review, definition of acceleration on 3-D and g-g-g diagram are established. For example, as a result of the evaluation, if the acceleration is out of range, the road is out of consistency. The paper shows calculation for change of acceleration on imaginary road under minimum design standard and the change tried to be applied to consistency. However accurate acceleration is not shown because the speed forecasting model is limited and the paper did not consider state of vehicles (suspension, tires and model of vehicles). If speed pronto is defined exactly, acceleration is calculated on all road shapes, such as. compound curve and clothoid curve. and then it is appled to consistency evaluation. Unfortunately, speed forecasting model on 3 -D road and on compound curves have rarely presented. Speed forecasting model and speed profile model need to be established and standard of consistency evaluation need to developed and verified by experimental vehicles.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.312-317
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• 2015

Seafarers can confront to evacuate from the ship with many reasons such as collision, grounding and fire accident. It believes that evacuation time from ship is very important element in order to increase survival rate in the contingency circumstance, however narrow and complex structure of ship is one of obstacle element against prompt evacuation. Taking into consideration the unique structure of ship compared to the structure of other facilities, speed of fire propagation on board ship is faster than the same size of other type facilities. Therefore, measures to prompt evacuation are required. But it comes with the behavioral constraints of the crews and passengers of the nature of operating in a complex structure with narrow vessels. Therefore, in this study, we propose a formula to be analyzed by theoretical approach and simulation methods to improve the survival rate for the crew and passenger of the ship through the ship's structural modification. We analyzed the temperature rise and visibility which are the most influential effects on the life safety in the event of fire by using a three-dimensional analysis of sight-only program Fire Dynamic Simulator (FDS) as analytical tools.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.4
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• pp.316-323
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• 2011

Purpose: The purpose of this study was to investigate the effect of different thread designs on the marginal bone stresses around dental implant. Materials and methods: Standard ITI implant(ITI Dental Implant System; Straumann AG, Waldenburg, Switzerland), 4.1 mm in diameter and 10 mm in length, was selected as control. Test implants of four different thread patterns were created based on control implant, i.e. maintaining all geometrical design of control implant except thread pattern. Four thread designs used in test implants include (1) small V-shape screw (model A), (2) large V-shape screw (model B), (3) buttress screw (model C), and (4) trapezoid screw (model D). Surface area for unit length of implant was 14.4 $mm^2$ (control), 21.7 (small V-shape screw), 20.6 (large V-shape screw), 17.0 (buttress screw) and 28.7 $mm^2$ (trapezoid screw). Finite element models of implant/bone complex were created using an axisymmetric scheme with the use of NISA II/DISPLAY III (Engineering Mechanics Research Corporation, Troy, MI, USA). A load of 100 N applied to the central node on the crown top either in parallel direction or at 30 degree to the implant axis (in order to apply non-axial load to the implant NKTP type 34 element was employed). Quantification and comparison of the peak stress in the marginal bone of each implant model was made using a series of regression analyses based on the stress data calculated at the 5 reference points which were set at 0.2, 0.4, 0.6, 0.8 and 1.0 mm from implant wall on the marginal bone surface. Results: Results showed that although severe stress concentration on the marginal bone cannot be avoided a substantial reduction in the peak stress is achievable using different thread design. The peak marginal bone stresses under vertical loading condition were 7.84, 6.45, 5.96, 6.85, 5.39 MPa for control and model A, B, C and D, respectively. And 29.18, 26.45, 25.12, 27.37, 23.58 MPa when subject to inclined loading. Conclusion: It was concluded that the thread design is an important influential factor to the marginal bone stresses.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.1
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• pp.59-70
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• 2020

This study was proceeded to empirically identify the start-up support policy as an element that affects the performance of the early start-ups and measure the effectiveness of the current start-up support policy, in order to suggest the direction future policies according to the study. To accomplish this the influence of the start-up support policy on the early start-ups was analyzed, and the differences according to the industry and growth stage of the start-ups, as the characteristics of the start-ups, were identified. The research subjects collected real data of 297 start-ups of the past three years that were selected for the Initial Start-Up Package project, and performed multiple regression analysis on the influence between variables, and hierarchical regression analysis on moderating effects. The summary of the study is as follows. First, as a result of identifying the influential relationship between the start-up support policy and the performance of the start-up, sales had made a significant impact on the start-up fund, start-up mentoring, and start-up infrastructure(space), while start-up education failed to show a significant effect on the increase in sales. In terms of employment, start-up mentoring was the only field that showed a significant influential relationship. Second, as a result of identifying the moderating effect of the start-up's industry and growth stage, the industry did not have a statistically significant influence, but the interactive effect was seen in start-up education. To be more specific in terms of the sales relationship of each industry, knowledge services turned out to be helpful in improving sales, while manufacturing turned out to be effective in improving sales regardless of being supported with start-up mentoring and start-up infrastructure (space). The sales relationship regarding the start-up growth stage was identified to be statistically significant. The preliminary stage was not statistically significant, while providing start-up mentoring and start-up funding were effective for start-up stage and growing stage, respectively. On the other hand, employment did not perform a significant influence on the start-up growth stage. This study analyzes the effectiveness the start-up support policy for early start-ups, identifies the need in differentiated support policies according to the characteristics of the start-ups, and suggests implications for the direction in which future policies should be made towards.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.363-375
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• 2013

Today, a shortage of the skilled operator has been intensified gradually and the necessity of an earthwork in extreme environment operators are difficult to access is increasing for the purpose of resource development and new living space creation. For this reason, an effort to develop an unmanned excavation robot for fully automated earthwork system is continuing globally. In Korea, a research consortium called 'Intelligent Excavation System' has been formed since 2006 as a part of Construction Technology Innovation Program of Ministry of Land, Transport and Maritime Affairs of Korea. Among detailed technologies of the Task Planning System is one of the core technologies of IES, this paper explains research and development process of the Local Area Design Module, which provides informatization unit to create automated excavators' work command information at operation level such as location, range, target, and sequence for excavation work. Designing of Local Area should be considered various influential factors such as excavator's specification, working mechanism, heuristics, and structural stability to create work plan guaranteed safety and effectiveness. For this research, conceptual and detail design of the Local Area is performed for analyzing design element and variable, and quantization method of design specification corresponding with heuristics and structural safety is generated. Finally, module is developed through constructed algorithm and developed module is verified.

• Journal of the Microelectronics and Packaging Society
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• v.17 no.4
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• pp.49-60
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• 2010

Semiconductor packages are increasingly moving toward miniaturization, lighter and high performance. Futhermore, packages become thinner. Thin packages will generate serious reliability problems such as warpage, crack and other failures. Reliability problems are mainly caused by the CTE mismatch of various package materials. Therefore, proper selection of the package materials and geometrical optimization is very important for controlling the warpage and the stress of the package. In this study, we investigated the characteristics of the warpage and the stress of several packages currently used in mobile devices such as CABGA, fcSCP, SCSP, and MCP. Warpage and stress distribution are analyzed by the finite element simulation. Key material properties which affect the warpage of package are investigated such as the elastic moduli, CTEs of EMC molding and the substrate. Geometrical effects are also investigated including the thickness or size of EMC molding, silicon die and substrate. The simulation results indicate that the most influential factors on warpage are EMC molding thickness, CTE of EMC, elastic modulus of the substrate. Simulation results show that warpage is the largest for SCSP. In order to reduce the warpage, DOE optimization is performed, and the optimization results show that warpage of SCSP becomes $10{\mu}m$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.714-721
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• 2018

In this study, we investigate a design technology intended to radically increase the buckling strength of vertically curved panels. Recent studies proposed a buckling strength formula which properly reflects the effect on the local plate buckling strength of flat plates when they are stiffened by closed section ribs. Herein, we attempted to quantitatively evaluate this effect on curved panels and to reveal the correlations with the design parameters. The commercial finite element software, ABAQUS, was used to build a three dimensional numerical model and numerical parametric studies were conducted to evaluate the variation of the buckling strength. In the case of flat panels, the local buckling strength of stiffened curved panels increases proportionally with increasing rotational stiffness of the closed-section ribs. After attaining a limiting value, an obvious tendency was found that the local buckling strength of the stiffened curved panel would converge towards a fixed value when the panels are supported along both sides. The parametric studies performed using the influential design parameters confirmed that the estimated partially-restrained curved panel strength is well correlated with the proposed formula.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.110-123
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• 2019

Traffic data is the most basic element necessary for transportation planning and traffic system operation. Recently, a method of estimating traffic flow characteristics using distance to a leading vehicle measured by an ADAS camera has been attempted. This study investigated the feasibility of the ADAS vehicle reflecting the distance error of image-based vehicle identification technology as a means to estimate the traffic flow through the normalized root mean square error (NRMSE) based on the number of lanes, traffic demand, penetration rate of probe vehicle, and time-space estimation area by employing the microscopic simulation model, VISSIM. As a result, the estimate of low density traffic flow (i.e., LOS A, LOS B) is unreliable due to the limitation of the maximum identification distance of ADAS camera. Although the reliability of the estimates can be improved if multiple lanes, high traffic demands, and high penetration rates are implemented, artificially raising the penetration rates is unrealistic. Their reliability can be improved by extending the time dimension of the estimation area as well, but the most influential one is the driving behavior of the ADAS vehicle. In conclusion, although it is not possible to accurately estimate the traffic flow with the ADAS camera, its applicability will be expanded by improving its performance and functions.