• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.424-430
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• 2021

Determining the cause of a traffic signal violation is difficult if the drivers' claims are contradictory. In this study, the process of identifying signal violations using a simulation was presented based on cases. First, statements from the driver or witness whose cause of the signal violation is unclear were excluded. Second, the final position, final location, damaged area, steering status, braking status, and road surface traces of the vehicle were collected. The impact point was investigated from the stop line. Third, simulation data were modified and entered until the collision situation of the accident vehicle and the final stop position were met. Fourth, if the simulation results were consistent with the crash situation, the facts were verified by cross-validation to conform to the driver's statement. The results of the simulation showed that the Lexus entered the left turn signal in the intersection at approximately 55 km/h. In comparison, the Sonata driver saw the vehicle straight ahead at the intersection, entered the 72 km/h intersection, and collided with the Lexus. Therefore, the Sonata was identified as a signal violation, and the claims of the Sonata driver, witnesses, and police were contradictory.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.78-83
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• 2021

Due to rapidly increasing air traffic congestion and airspace restrictions, the International Civil Aviation Organization (ICAO) is urging all aircraft to use SBAS by 2025, in order to implement Performance-based navigation to increase airspace capacity. In line with this, research and development of Korean-style SBAS, which reflects the characteristics of Korea's airspace environment, continues in Korea. Since there is no flight inspection procedure for performance testing and verification of SBAS in Korea yet, this paper analyzes FAA, ICAO Regulations, and laws enacted by the Ministry of Land, Infrastructure and Transport to derive essential evaluations and parameters of Korean SBAS, and presents the optimal design using RTK-DGPS as a position fixing system.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.515-520
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• 2020

The development of autopilot system and flight management system (FMS) equipment in today's aircraft navigation can be attributed to the reduction of pilots' workload and the navigation safety. The effect of autopilot and FMS equipment is greater, especially in heavy airport traffic or complicated of the departure. However, some airport specific departure procedures result in an uncommanded turn event due to an error in the FMS, causing aircraft to deviate from the center line of the route. With most departure procedures requiring area navigation (RNAV) operation, pilot situation awareness and corrective action are the only ways to minimize aircraft deviation to maintain the safety of area navigation. Through analysis of the occurrence status of the uncommended turn event by aircraft type, airport and flight phase, and comparative analysis of the survey results of foreign airlines and the airlines self-reduction plan with the aircraft manufacturer's corrective action, it is intended to give implications for the need for more fundamental measures to prevent recurrence of such events.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.4
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• pp.1-8
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• 2021

In this paper, we propose an approach that combines the technological advantages of P2P and cloud computing to support MMOGs that allowing a huge amount of users worldwide to share a real-time virtual environment. The proposed P2P system based on cloud computing can provide a greater level of scalability because their more resources are added to the infrastructure even when the amount of users grows rapidly. This system also relieves a lot of computational power and network traffic, the load on the servers in the cloud by exploiting the capacity of the peers. In this paper, we describe the concept and basic architecture of cloud computing-based P2P Systems for scalability of MMOGs. An efficient and effective provisioning of resources and mapping of load are mandatory to realize this architecture that scales in economical cost and quality of service to large communities of users. Simulation results show that by controlling the amount of cloud and user-provided resource, the proposed P2P system can reduce the bandwidth at the server while utilizing their enough bandwidth when the number of simultaneous users keeps growing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.4
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• pp.562-570
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• 2022

The supply expansion of 5G services and personal smart devices has caused the sharp increase of data traffic and the demand of various services. Again, these facts have resulted in the huge demand of network bandwidth. However, existing network technologies using electronic signal have reached the limit to accommodate the demand. Therefore, in order to accept this request, optical internet has been studied actively. However, optical internet still has a lot of problems to solve, and among these barriers a very urgent issue is to develop QoS technologies. Hence, in order to achieve service differentiation between classes in optical internet, especially in OBS network, a new QoS method automatically tuning the size of data bursts is proposed in this article. Especially, the algorithm suggested in this article is based on fiber delay line.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.6
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• pp.715-725
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• 2021

When constructing railway stations, gates shall be located in appropriate locations for convenient use. However, to reduce construction costs, the number of gates was minimized and the location was not appropriately placed to the direction of many users. This study proposed a method to calculate the benefits of additional gate installations using the improvement of pedestrian traffic flow, occupied area and travel time as economic effects. In particular, a method of estimating the percentage of people using certain gates and the number of people by route within the station was proposed. This method was applied to analyze the effect of additional gates to Gwang-myeong Station on the Shinansan Line, which is to be opened in 2025. The effect has only improved in mobility. The first year of its opening was estimated at 5.91 billion won for mobility and 75.8 billion won for cost, and the B/C was 1.21 for 30 years after its opening. It is expected that this method will be applied to systematic effect analysis when additional gates are installed at unopened railway stations as well as existing railway stations.

• Journal of People, Plants, and Environment
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• v.23 no.1
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• pp.101-114
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• 2020

This study focused on the composition of the exterior space of Parkjinsagoga, the types of gardens and planting and the landscape characteristics of walls, and examined its meaning as modern garden remains. Parkjinsagoga is a modern Korean house that harmonizes traditionality and practicality, and is an invaluable material for research not only on architecture but also on changes in the gardens of upper-class gardens. Its exterior space can be divided largely into An-chae (inner house), Outer Sarang-chae (outer house) and Inner Sarang-chae areas, and a garden was created in each yard (inner garden). In particular, one thing noticeable is that the yard of Inner Sarang-chae, unlike traditional gardening styles, was actively decorated. At the center of the yard of Inner Sarang-chae, two atypical planters and artificial moundings were created and the traffic line of the garden was designed to enjoy them while walking. An atypical pond was created on one of the artificial moundings and trees and shrubs were densely planted. Natural stones were also placed. The style seemed to be affected by Japanese gardens. These characteristics observed in the gardens of Parkjinsagoga are closely related to the transitional characteristics that traditional gardens started to show in modern times. A total of 35 families and 57 species were planted in the gardens of Parkjinsagoga and there were 19 species of tall trees, 20 species of shrubs and 17 species of flowering plants. The number of species planted in the garden of Inner Sarang-chae was the highest, and a total of 22 species of tall trees and shrubs. The walls in Parkjinsagoga were basically earth and rock-fill walls but their materials and patterns differed depending on the type of spaces. Four types of walls were found to be introduced to the house.

• Archives of Craniofacial Surgery
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• v.24 no.4
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• pp.167-173
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• 2023

Background: Mandibular split fractures, in which the fracture occurs exclusively in the posterior wall, are uncommon. This study aimed to enhance clinicians' understanding of mandibular split fractures and offer insights for future research. Methods: This study included six patients who visited our hospital between January 2020 and June 2023 and were diagnosed with mandibular split fractures. We retrospectively collected data from patients' medical records on their age, sex, symptoms, mechanism, impact site, associated injuries, and treatment method, as well as the location, pattern, and number of fractures observed on computed tomography (CT) and panoramic images. The frequency of split fractures among all mandibular fractures was calculated. Results: The six patients included three men (50%) and three women (50%), ranging in age from 20 to 71 years (mean age, 49.8 years). The split fractures were located in the symphysis in one patient (16.7%), symphysis to parasymphysis in two patients (33.3%), parasymphysis in one patient (16.7%), and parasymphysis to the body in two patients (33.3%). Four patients (66.7%) had condylar head fractures, while two patients (33.3%) had single split fractures. The mechanism of trauma was a slip-down incident in four cases (66.7%), while two cases (33.3%) were caused by motorcycle traffic accidents. Four patients (67%) underwent intermaxillary fixation, while two patients (33%) improved with conservative treatment. Split fractures were diagnosed in all six patients on CT, whereas the fracture line was not clearly visible on panoramic images. Mandibular split fractures accounted for 5.6% of all mandibular fractures. Conclusion: This study provides insights into the clinical characteristics of rare mandibular split fractures and the diagnostic imaging findings. Furthermore, CT scans and three-dimensional image synthesis-instead of panoramic images-may be essential for accurately diagnosing mandibular fractures, including mandibular split fractures, in the future.

• Journal of the Korean GEO-environmental Society
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• v.23 no.4
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• pp.29-39
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• 2022

In order to solve the serious traffic congestion in seoul metropolitan city, large-scale underground space development such as underpasses, deep underground roads, and GTX (Great Train eXpress) is being carried out. In order to minimize the impact of the adjacent seoul metro line A pier foundation and stability due to the construction of the underground road in Seoul, earth retaining structures were reinforced and the foundation was reinforced as well. In this study, three-dimensional finite element mehtod analysis was performed to evaluate the effect on adjacent construction and to review the stability of the underpass excavation work. The reinforcement effect was quantitatively analyzed through numerical analysis. As a result of the analysis, compared to the result of performing the existing reinforcement when overlapping CIP and ground reinforcement grouting were performed, the displacement of the earth retaining structures was reduced by more than 50%, and stress of the foundation piles were also reduced by more than 45%. Based on the analysis of the numerical analysis results, it was confirmed that the displacement of the walls of earth retaining structures during adjacent construction should be strictly controlled.

• Korean Journal of Construction Engineering and Management
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• v.24 no.1
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• pp.21-30
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• 2023

Excessive complaints and traffic jams occurred as customers who visited the Drive-thru waited in a long line. Company S recommends DT Pass to reduce the queues. Therefore, this study confirmed the improvement in performance of the queue increasing the number of stores operated by two servers insteaol of one using a queue model. And then confirmed performance improvement by dividing them into DT and DT Pass. After that, the L value derived through the queue model and the number of queues in each store were compared to calculate the number of queues to be additionally provided. Through this, the validity of selecting the minimum number of queues in the future is verified based on the results derived in this study.