• Journal of Navigation and Port Research
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• v.44 no.3
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• pp.174-180
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• 2020

With the removal of underwater obstacles in the Busan New Port, the water depth of the pier has been secured up to 17m, and the port authority is constantly responding to the trend of container vessels becoming larger. Also, in 2020, 24,000TEU class container ships are entering to the port, and it is planned to secure the depth in the port to 23 m later in line with this trend. Mega container ships must check in advance the factors to be considered depending on the situation at the time, and for this, it is judged that information sharing among stakeholders is necessary. In this paper, to understand the effect of the corresponding route because of the mega container ships, a transit safety evaluation was conducted based on statistical data on ship entry and departure and maneuver characteristics of corresponding ships. The result showed that the transit of the mega container ships has increased up to 8.4% comparing to the risk of 4,000TEU class container ships. Additionally, safety measures such as minimum safety depth and tug operation plans were presented by gathering opinions on operational characteristics from the perspective of pilotage for safe transit in the Busan New Port area. Through this, it is considered that it will be possible to contribute to the prevention of accidents when entering and leaving the Busan New Port.

• Archives of Plastic Surgery
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• v.38 no.5
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• pp.669-673
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• 2011

Purpose: The authors have conducted a series of anatomic studies on the factors affecting shape of a lower vault in Asian noses. The results of the studies showed that prominence of alar lobule is mainly affected by the volumes of the dilator naris anterior and posterior muscles and the insertions of the dilator naris posterior muscles. However, information on its clinical availability is yet insufficient. The present study was undertaken for clinical purpose to find out the effect of dilator naris muscle resection on the correction of prominent alar lobule. Methods: Six patients who were treated by dilator naris muscle resection with a long-term follow-up of more than 1 year were involved in this study. Rhinoplasties were performed via endonasal approaches with resecting dilator naris anterior and posterior muscles by sharp scissor. The effect of the dilator naris muscle resection on alar prominence was investigated by measuring ratio of the short axis to the long axis of a nostril (SA/LA) pre-and postoperatively. The visual analog scale (VAS) was also used to evaluate satisfaction of patients. An average follow-up time was $15.6{\pm}3.7$ months. Results: Having lost the dilating and lateral pulling effects of the dilator naris muscles, the alar lobule shifted medially and alar lobule shapes improved. SA/LA significantly improved (preoperatively $0.71{\pm}0.11$ and postoperatively $0.58{\pm}0.08$; $p$ <0.05). The VAS score was also increased postoperatively (preoperatively $3.2{\pm}1.8$ and postoperatively $8.7{\pm}1.2$; $p$ <0.05). A mild degree of hyperpigmented scar was noted in one alar lobule. Otherwise, there was no case of postoperative complication. Conclusion: Our results suggest that prominent alar lobule could be modified by resecting the attachment of the dilator naris muscles. This maneuver removes the function of dilator naris muscles, then may produce a more aesthetically acceptable alar lobule shape.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.2
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• pp.95-106
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• 2021

Side-jets enable the immediate maneuver of a missile compared to control surfaces; however, they may cause adverse effects on aerodynamic coefficients, for they interfere with freestream. To find out the impact of side-jets on aerodynamic coefficients, we simulate side-jets as air gas and utilize multi-fidelity models to evaluate differences between aerodynamic coefficients obtained with and without side-jets. We computed differences in aerodynamic coefficients to investigate side-jet effects for the changes of a Mach number, a bank angle, and an angle of attack. As a result, asymmetrically developed side-jets affect the longitudinal force and moment coefficients, and the lateral force and moment coefficients drastically change in-between -30 and 30 degrees of bank angles. In contrast, side-jets hardly influence the axial force coefficients. As for the axial moment coefficient, we could not determine the side-jet effect due to a lack of aerodynamic coefficient samples in the Mach number. All in all, we confirm that side-jets lead to the change of a missile attitude as they considerably vary the longitudinal and lateral aerodynamic coefficients.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.183-200
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• 2022

A variety of simulation approaches based on automated driving technologies have been proposed to develop traffic operations strategies to prevent traffic crashes and alleviate congestion. The maneuver of simulated autonomous vehicles (AVs) needs to be realistic and be effectively differentiated from the behavior of manually driven vehicles (MVs). However, the verification of simulated AV maneuvers is limited due to the difficulty in collecting actual AVs trajectory and interaction data with MVs. The purpose of this study is to develop a methodology to evaluate the suitability of AV maneuvers based on both driving and traffic simulation experiments. The proposed evaluation framework includes the requirements for the behavior of individual AVs and the traffic stream performance resulting from the interactions with surrounding vehicles. A driving simulation approach is adopted to evaluate the feasibility of maneuvering of individual AVs. Meanwhile, traffic simulations are used to evaluate whether the impact of AVs on the performance of traffic stream is reasonable. The outcome of this study is expected to be used as a fundamental for the design and evaluation of transportation systems using automated driving technologies.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.3
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• pp.945-953
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• 2018

In this paper, we use 3-D LIDAR for obstacle detection and avoidance maneuver for autonomous unmanned operation. It is aimed to avoid obstacle avoidance in unmanned water under marine condition using only single sensor. 3D lidar uses Quanergy's M8 sensor to collect surrounding obstacle data and includes layer information and intensity information in obstacle information. The collected data is converted into a three-dimensional Cartesian coordinate system, which is then mapped to a two-dimensional coordinate system. The data including the obstacle information converted into the two-dimensional coordinate system includes noise data on the water surface. So, basically, the noise data generated regularly is defined by defining a hypothetical region of interest based on the assumption of unmanned water. The noise data generated thereafter are set to a threshold value in the histogram data calculated by the Vector Field Histogram, And the noise data is removed in proportion to the amount of noise. Using the removed data, the relative object was searched according to the unmanned averaging motion, and the density map of the data was made while keeping one cell on the virtual grid map. A polar histogram was generated for the generated obstacle map, and the avoidance direction was selected using the boundary value.

• Journal of the Korea Society for Simulation
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• v.33 no.2
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• pp.37-44
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• 2024

The Korean Helicopter Development Program has successfully introduced the Surion helicopter, a versatile multi-domain operational aircraft that replaces the aging UH-1 and 500MD helicopters. Specifically designed for maneuverability, the Surion plays a crucial role in low-altitude tactical maneuvers for personnel transportation and specific missions, emphasizing the helicopter's survivability. Despite the significance of its low-altitude tactical maneuver capability, there is a notable gap in research focusing on multi-mission tactical maneuvers that consider the risk factors associated with deploying the Surion in the presence of enemy air defenses. This study addresses this gap by exploring a method to enhance the Surion's low-altitude maneuvering paths, incorporating information about enemy air defenses. Leveraging the Proximal Policy Optimization (PPO) algorithm, a reinforcement learning-based approach, the research aims to optimize the helicopter's path planning. Visualized experiments were conducted using a Surion model implemented in the Unity environment and ML-Agents library. The proposed method resulted in a rapid and stable policy convergence for generating optimal maneuvering paths for the Surion. The experiments, based on two key criteria, "operation time" and "minimum damage," revealed distinct optimal paths. This divergence suggests the potential for effective tactical maneuvers in low-altitude situations, considering the risk factors associated with enemy air defenses. Importantly, the Surion's capability for remote control in all directions enhances its adaptability in complex operational environments.

• Journal of Astronomy and Space Sciences
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• v.41 no.1
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• pp.43-60
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• 2024

Korea Pathfinder Lunar Orbiter (KPLO) is South Korea's first space exploration mission, developed by the Korea Aerospace Research Institute. It aims to develop technologies for lunar exploration, explore lunar science, and test new technologies. KPLO was launched on August 5, 2022, by a Falcon-9 launch vehicle from cape canaveral space force station (CCSFS) in the United States and placed on a ballistic lunar transfer (BLT) trajectory. A total of four trajectory correction maneuvers were performed during the approximately 4.5-month trans-lunar cruise phase to reach the Moon. Starting with the first lunar orbit insertion (LOI) maneuver on December 16, the spacecraft performed a total of three maneuvers before arriving at the lunar mission orbit, at an altitude of 100 kilometers, on December 27, 2022. After entering lunar orbit, the commissioning phase validated the operation of the mission mode, in which the payload is oriented toward the center of the Moon. After completing about one month of commissioning, normal mission operations began, and each payload successfully performed its planned mission. All of the spacecraft operations that KPLO performs from launch to normal operations were designed through the system operations design process. This includes operations that are automatically initiated post-separation from the launch vehicle, as well as those in lunar transfer orbit and lunar mission orbit. Key operational procedures such as the spacecraft's initial checkout, trajectory correction maneuvers, LOI, and commissioning were developed during the early operation preparation phase. These procedures were executed effectively during both the early and normal operation phases. The successful execution of these operations confirms the robust verification of the system operation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.4
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• pp.324-331
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• 2024

The height of large car and truck carriers from the keel to the wheel house is 44 ~ 46 m, and as the car-carriers increases in size, it exhibits the 'top heavy' characteristic, where the upper section is heavier than the lower section. This study aims to estimate the maximum outward heel angle of the Golden Ray car-carrier (G-ship) during turning maneuvers for accident investigation and the prevention of similar accidents. The theoretically calculated maximum outward heel is 7.5° (at 19 kn, rudder angle 35°) with a GM of +3.0 m or higher, and 16.7° with a GM of +1.85 m. Meanwhile the experimentally modified maximum outward heel is 10.5° (at 19 kn, rudder angle 35°) with a GM of +3.0 m or higher, and 23.3° with a GM of +1.85 m. The G-ship is maneuvered during an accident at a speed of 13 kn, at starboard rudder angle of 10° to 20°, it changes course from 038°(T) to 105°(T) based on the instructions of the on-board pilot. At this time, the maximum outward heel is estimated to be between 7.8° and 10.9° at the port side, which is 2.2 times higher than the normal outward heel. In the IS code, cargo ships are required to exhibit a minimum GoM of +0.15 m or more. The maneuvered G-ship exhibits a GoM of +1.72 m. It is not maneuvered because it fails to satisfy the international GoM criteria and because its GoM is insufficient to counteract the heeling moment during the maneuver. This study is performed based on accident-investigation results from the Korea Maritime Safety Tribunal and the USCG.

• Clinical and Experimental Pediatrics
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• v.52 no.11
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• pp.1267-1272
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• 2009

Purpose:We examined the ability of preschool aged children to meet the American Thoracic Society (ATS) and European Resiratory Society (ERS) goals for spirometry quality and tried to find out the major factor for improving the rate of success of spiromety test in this age group. Methods:Spirometry was performed in 2-6 aged 155 children with chronic cough or suspicious asthma with the recording of maneuver quality measures of forced expiratory time, end-of-test volume, back-extrapolated volume (Vbe), and forced vital capacity (FVC), as well as flow-volume curve. The subjects were tested several times and the two best results in each subject were selected. All criteria for quality control were suggested by ATS/ERS guidelines. The criteria for starting of the test was Vbe <80 mL and Vbe/FVC <12.5%. The criteria for repeatability of the test was that second highest FVC and FEV1 are within 100 ml or 10% of the highest value, whichever is greater. For the criteria for termination of the test for preschool aged children, we evaluated the flow-volume curve Results:As getting older, the success rate of spirometry increased and rapidly increased after 3 years old. Total success rate of the test was 59.4% (2 years old - 14.3%, 3 years old - 53.7%, 4 years old - 65.1%, 5 years old - 69.7%, 6 years old- 70.8%). The percentage of failure to meet the criteria for starting the test was 6.5%, repeatability of the test was 12.3% and end of the test was 31%. There was a significant difference only in age between success group and failure group. Evaluating the quality control criteria of previous studies, the success rate increased with age. Conclusion:About 60% of preschool aged children met ATS/ERS goals for spirometry test performance and the success rate was highly correlated with age. It is clearly needed that developing more feasible and suitable criteria for quality control of spirometry test in preschool aged children.

• Korean Security Journal
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• no.48
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• pp.259-285
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• 2016

As the need for anti-terrorism legislation has been continuously argued, Anti-terrorism act has been enacted and enforced. On the other hand, there still remain a lot of points to be discussed regarding the definition of the concept of terrorism, matters of human rights violations, strengthening authority of the investigation and intelligence agencies, and mobilization military forces for the suppression of terrorism. Also, reviewing Anti-terrorism act and its enforcement ordinance draft, this legislation seems to regulate terrorist groups like IS. If so, in the case of terrorism of North Korea or domestic anti-government organizations, whether this law would be applied could become an issue. In the case of terrorism of North Korea, Ministry of National Defense has a right of commandership in the military operations, however, it is also possible to apply the article 4 of Natural Security Act a crime of performing objective-or a crime of foreign exchange on Criminal law as legal grounds for not military terrorisms but general investigations. Therefore, it is necessary to involve consideration about this matter. Furthermore, in the view of investigation, Anti-terrorism act and its enforcement ordinance draft do not mention Supreme Prosecutors Office and Ministry of Justice that conduct investigations. In the case of terrorism, the police and prosecution should conduct to arrest criminals and determine crimes at the investigation stage, however, any explicit article related to this content in Anti-terrorism act and its enforcement ordinance draft was unable to be found. Although Anti-terrorism act is certainly toward preventive aspects, considering some matters such as prevention, actions on the scene, maneuver after terrorism, arresting terrorists, investigation direction, cooperation, and mutual assistance, it is necessary to reflect these contents in Anti-terrorism act. In other words, immediately after terrorists attacks, it is possible to mobilize the military operations by Integrated Defense act in order to arrest them in the case of military terrorism. Nevertheless, because both military terrorism and general one are included in the investigation stage, it needs to begin an investigation under the direction of the prosecution. Therefore, above all, a device for finding out the truth behind the case at the investigation stage is not reflected in the current Anti-terrorism act and its enforcement ordinance draft. Accordingly, if National Intelligence Service approaches information at the prevention level in this situation, it may be necessary to come up with follow-up measures of the police, the prosecution, and military units.