• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.43-50
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• 2002

This paper presents the new gait implementation of a biped robot with smooth walking using 3-dimensional continuous trunk motion and kick action of ankle joints. Trajectory generation ova trunk is performed not on a unit gait but on a whole walking interval. In applying kick action such as heel-touch or toe-off, varying coordinate system was employed for the simplification of the kinematic analysis. Desired ZMP (zero moment point) is also changed to implement the efficient kick action. As a result, balancing motion of the proposed gait was much more decreased than that of conventional one. Moreover, robot\\`s walking behavior is very smooth, natural and similar to the pace of a human. The walking experiment system is composed of eight AC servo motors and a DSP controller. The walking simulation and the experimental results are shown using the proposed new walking algorithm.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1394-1405
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• 2022

The importance of ensuring the inherent safety and security has been more emphasized in recent years to demonstrate the integrity of nuclear facilities under external human-induced events (e.g. aircraft crashes). This work suggests a simulation methodology to effectively evaluate the impact of a commercial aircraft engine onto a dry storage facility. A full-scale engine model was developed and verified by Riera force-time history analysis. A reinforced concrete (RC) structure of a dry storage facility was also developed and material behavior of concrete was incorporated using three constitutive models namely: Continuous Surface Cap, Winfrith, and Karagozian & Case for comparison. Strain-based erosion limits for concrete were suitably defined and the local responses were then compared and analyzed with empirical formulas according to variations in impact velocity. The proposed methodology reasonably predicted such local damage modes of RC structure from the engine missile, and the analysis results agreed well with the calculations of empirical formulas. This research is expected to be helpful in reviewing the dry storage facility design and in the probabilistic risk assessment considering diverse impact scenarios.

• International Journal of Computer Science & Network Security
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• v.23 no.5
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• pp.163-171
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• 2023

The intelligent transportation system has made a huge leap in the level of human services, which has had a positive impact on the quality of life of users. On the other hand, these services are becoming a new source of risk due to the use of data collected from vehicles, on which intelligent systems rely to create automatic contextual adaptation. Most of the popular privacy protection methods, such as Dummy and obfuscation, cannot be used with many services because of their impact on the accuracy of the service provided itself, they depend on changing the number of vehicles or their physical locations. This research presents a new approach based on the shuffling Nicknames of vehicles. It fully maintains the quality of the service and prevents tracking users permanently, penetrating their privacy, revealing their whereabouts, or discovering additional details about the nature of their behavior and movements. Our approach is based on creating a central Nicknames Pool in the cloud as well as distributed subpools in fog nodes to avoid intelligent delays and overloading of the central architecture. Finally, we will prove by simulation and discussion by examples the superiority of the proposed approach and its ability to adapt to new services and provide an effective level of protection. In the comparison, we will rely on the wellknown privacy criteria: Entropy, Ubiquity, and Performance.

• Fire Science and Engineering
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• v.28 no.1
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• pp.31-36
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• 2014

Recently, the safety assessments with using the various evacuation programs are performed for improving the performance of fire and evacuation safety in the building. Generally, the evacuation programs can simulate the human behavior in fire situation by applying the variation of the movement speed and Fractional Effective Dose (FED) index in the smoke. However, if the simulation is performed without optional setting around the fire, the agents do not avoid the fire and they move through the fire. Therefore in this study, we define the radiative repulsion force which exists between the fire and the agents. Moreover, we modify the Helbing's movement model by adding the radiative repulsion force. As a result of the modified movement model, all agents move around the fire and they do not enter the upper bound area of radiative heat flux, $2.4kW/m^2$. From these results, we verified the reliability of the modified movement model.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.251-258
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• 2018

Recently, due to the increase in the traffic volume of vehicle, the collision of the vehicle collision has been increased so that the neck injuries of the passengers has been increased. In order to prevent this, vehicle collision analysis research using computer simulation has been actively carried out in consideration of the design point of car seat. In this study, I used the MADYMO program for analyzing the passenger behavior using a BioRID II dummy, and predicted the neck injuries of passengers according to the change of the backset at the rearward collision of the driving speed of 16km/h. As a result, it was found that the shorter the backset, the shorter the contact start time but the contact completion time was almost the same and the T1 acceleration showed that the acceleration increased with the backset. In addition, the tensile strength increases as the backset increases, and NIC (Neck Injury Criterion) increases as the head speed reaches the headrest.

• Elastomers and Composites
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• v.44 no.2
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• pp.98-105
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• 2009

The cochlea of the inner ear has two core components, basilar membrane and hair cells. The basilar membrane disperses incoming sound waves by their frequencies. The hair cells are on the basilar membrane, and they are the sensory receptors generating bioelectric signals. In this paper, a biomimetic technology using ZnO piezoelectric nano-pillar was studied as the part of developing process for artificial cochlea and novel artificial mechanosensory system mimicking human auditory senses. In particular, ZnO piezoelectric nano-pillar was fabricated by both low and high temperature growth methods. ZnO piezoelectric nano-pillars were grown on solid (high temperature growth) and flexible (low temperature growth) substrates. The substrates were patterned prior to ZnO nano-pillar growth so that we can selectively grow ZnO nano-pillar on the substrates. A multi-physical simulation was also conducted to understand the behavior of ZnO nano-pillar. The simulation results show electric potential, von Mises stress, and deformation in the ZnO nano-pillar. Both the experimental and computational works help characterize and optimize ZnO nano-pillar.

• Journal of Navigation and Port Research
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• v.46 no.1
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• pp.18-25
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• 2022

MOF strengthen the law and institutions for safety management after the capsize accident of passenger ship "Sewol" on April 16, 2014. Nevertheless, about 13 cases of marine accidents such as collisions, contact, and stranding have occurred in coastal passenger ships over the past 5 years. Particularly, according to the judgment of KMST, most of the main causes of passenger ship accidents occurred within harbor areas because of the master's improper ship-handling or inattention. And so, this study analyzed four cases of marine accidents on passenger ships that occurred in the port areas and examined the environmental, institutional, material, and human factors that contributed to the master's improper ship-handling and behavior, and the results are as follows. First, as an environmental factor, the size of the turning basin was not enough. Second, as an institutional factor, the VTS control was not properly supported, the master lacked sufficient training for safe ship-handling in the port area and up-to-date charts were not provided. Third, as a material factor, the digital type speed log capable of the ship's speed in real-time was not installed on the ship's wing bridge. Lastly, as a human factor, the master could not take proper bridge resources and the passage plan was not proper. Therefore, it is suggested in this paper that the size of the turning basin should be adjusted to meet the prescribed standards, the master of passenger ships should receive the ship-handling simulation training among other safety training to ensure safe ship-handling of the master in the port area as improvement measures.

• Informatization Policy
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• v.28 no.3
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• pp.3-22
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• 2021

This article reviews previous literature on the metaverse and attempts to provide a refined definition for this phenomenon. Metaverse has recently been in the spotlight among discussions by the industry and the media while a consensus on the exact definition of metaverse is yet to be determined. Since Neal Stephenson first coined the term metaverse in his novel "Snow Crash" in 1992, the Acceleration Studies Foundation (ASF) was the first to analyze the concept of metaverse in 2007. While ASF's effort did not receive much spotlight it may have deserved, metaverse gained much attention in the fall of 2020 when NVIDIA announced its real-time simulation and collaboration platform for 3D production named "Omniverse" as a next-generation alternative for the Internet along with Roblox defining its service as metaverse during its IPO. Since then, metaverse has been commonly recognized as a world where we can cross over reality and virtuality. Based on the two axes and four scenarios proposed by the ASF, we review the literature across four realms as follows - virtual reality, mirror world, augmented reality, and lifelogging. Then, we examine the issues with the existing definition of metaverse and propose an alternative explanation by focusing on human behavior and user experience. Finally, we reassess the concept of metaverse and incorporate human communication, reality-based and virtual-based activities, and eXtended reality as elements to properly define metaverse.

• Archives of design research
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• v.20 no.3 s.71
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• pp.247-256
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• 2007

Aging brings color-weakness to the eye due to yellowed eye sight. The 87% of information required for human behavioral decisions are visually perceived. Therefore, the color-weakness will affect behavior in many ways. Most of previous research regarding color planning for the aged focuses on discovering their preferred colors and reflecting the colors on facility color planning. But such research failed to identify the confused range of color cognitions due to the color weakness of the aged. The purpose of this study is to propose a design guide for fee-charging residential facilities for the elderly, reflecting upon color perception characteristics. An experimental simulation on aged vision using the UV filter and Y-2 filter, YA-3 filter alternating for general eyesight, 70 year-old and late 80 year-old was conducted. The results of this study are as follow : color perception is changed by crystalline lens aging process and yellowed eye sight. The recognition arrangement of colors was preferred to contrast harmony rather than similarity harmony and the dominant color is a warm color rather than a cool color.

• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.806-816
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• 2011

Interest about social security has recently increased in favor of safety for infrastructure. In addition, advances in computer vision and pattern recognition research are leading to video-based surveillance systems with improved scene analysis capabilities. However, such video surveillance systems, which are controlled by human operators, cannot actively cope with dynamic and anomalous events, such as having an invader in the corporate, commercial, or public sectors. For this reason, intelligent surveillance systems are increasingly needed to provide active social security services. In this study, we propose a core technique for intelligent surveillance system that is based on swarm robot technology. We present techniques for invader enclosing using swarm robots based on multiple distributed object environment. The proposed methods are composed of three main stages: location estimation of the object, specified object tracking, and decision of the cooperative behavior of the swarm robots. By using particle filter, object tracking and location estimation procedures are performed and a specified enclosing point for the swarm robots is located on the interactive positions in their coordinate system. Furthermore, the cooperative behaviors of the swarm robots are determined via the result of path navigation based on the combination of potential field and wall-following methods. The results of each stage are combined into the swarm robot-based invader-enclosing technique on multiple distributed object environments. Finally, several simulation results are provided to further discuss and verify the accuracy and effectiveness of the proposed techniques.