• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.5
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• pp.53-58
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• 2011

In this paper, we firstly propose a novel cooperative transmission protocol, which utilizes the advantages of mid-notes in the route from the source to the destination. Taking benefits from balancing between the received packet from the source and acknowledge message from the destination, the mid-node between the source and the destination is firstly considered to be the broadcaster. If its signal is successfully received from the source, it leads to consider the next nodes, which has closer distance to the destination than it. If one of these nodes correctly receives the signal, it performs broadcasting the signal to the destination instead of mid-node. Otherwise, the mid-node directs attention to these nodes being near to the destination. As the result, some nodes are unnecessary to be considered and passed over time. After that, we analyze some published selection relaying schemes based on geographic information to choose the best nodes instead of the instantaneous SNR as before. Finally, simulation results are given to demonstrate the correctness of the performance analyses and show the significant improvement of the selection relaying schemes based geographic information compared to the other ones.

• Journal of the Korean Society for Railway
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• v.10 no.2 s.39
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• pp.112-116
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• 2007

In this paper, we proposed a selection and application recommendations of ZnO arresters for DC electric traction vehicles. To decide the Continuous Operating Voltage($U_C$), the Rated Voltage($U_r$), and the Nominal Discharge Current(In), we measured and analyzed system voltages and surge currents flowing the arrester installed on a DC electric traction vehicle under running state. System voltages measured up to 1,800 V in 1,500 V-system, and surge currents were recorded up to 3 times per a running-service-route and their magnitudes were ranges of $150A{\sim}2kA$. From these results and a standard EN50163, we could proposed $U_C$, $U_r$, and In available for the 1,500 VDC electric traction vehicles.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.2
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• pp.115-125
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• 2015

This paper presents a Cuckoo search algorithm to secure adversaries misdirecting multi-hop routing in Mobile ad hoc networks (MANETs) using a robust Trust Predicated Routing Framework with an optimized cluster head selection. The clustering technique designed in this framework leads to efficient routing in MANETs. The heavy work load in the node causes an energy drop in cluster head, which leads to re-clustering of the group, and another cluster head is selected to avoid packet loss during data transmission. The problem in the re-clustering process is that the overall efficiency of the routing process is reduced and the processing time is increased. A Cuckoo search based optimization algorithm is proposed to solve the problem of re-clustering by selecting the secondary cluster head within the initially formed cluster group and eliminating the reclustering process. The proposed framework enables a node to select a reliable and secure route for MANET and the performance can be evaluated by comparing the simulated results with the AODV routing protocol, which shows that the performance of the proposed routing protocol are improved significantly.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1519-1520
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• 2006

This paper describes a selection and application recommendations of ZnO arresters on DC electric traction vehicles. We measured and analyzed the system voltages applied to arresters and the surge currents flowing arresters on DC electric traction vehicles under operation to decide the Continuous Operating Voltage($U_C$), the Rated Voltage($U_R$), and the Nominal Discharge Current($I_n$). System voltages measured up to 1,800 V during anti-breaking in 1,500 V-system, and surge currents were recorded up to 3 times per running-service-route and their magnitudes were ranges of $150A{\sim}2kA$. From these results and the standard EN50163, we proposed the Continuous Operating Voltage($U_C$) the Rated Voltage($U_R$) for the $1,500V_{dc}$ electric traction vehicles.

• Geomechanics and Engineering
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• v.30 no.1
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• pp.75-91
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• 2022

This paper aims to show how to use several Machine Learning (ML) methods to estimate the TBM penetration rate systematically (TBM-PR). To this end, 1125 datasets including uniaxial compressive strength (UCS), Brazilian tensile strength (BTS), punch slope index (PSI), distance between the planes of weakness (DPW), orientation of discontinuities (alpha angle-α), rock fracture class (RFC), and actual/measured TBM-PRs were established. To evaluate the ML methods' ability to perform, the 5-fold cross-validation was taken into consideration. Eventually, comparing the ML outcomes and the TBM monitoring data indicated that the ML methods have a very good potential ability in the prediction of TBM-PR. However, the long short-term memory model with a correlation coefficient of 0.9932 and a route mean square error of 2.68E-6 outperformed the remaining six ML algorithms. The backward selection method showed that PSI and RFC were more and less significant parameters on the TBM-PR compared to the others.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.10
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• pp.2658-2681
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• 2023

In edge computing scenarios, IoT end devices play a crucial role in relaying and forwarding data to significantly improve IoT network performance. However, traditional routing mechanisms are not applicable to this scenario due to differences in network size and environment. Therefore, it becomes crucial to establish an effective and reliable data transmission path to ensure secure communication between devices. In this paper, we propose a trusted path selection strategy that comprehensively considers multiple attributes, such as link stability and edge cooperation, and selects a stable and secure data transmission path based on the link life cycle, energy level, trust level, and authentication status. In addition, we propose the Stability-based On-demand Multipath Distance Vector (STAOMDV) protocol based on the Ad hoc AOMDV protocol. The STAOMDV protocol implements the collection and updating of link stability attributes during the route discovery and maintenance process. By integrating the STAOMDV protocol with the proposed path selection strategy, a dependable and efficient routing mechanism is established for IoT networks in edge computing scenarios. Simulation results validate that the proposed STAOMDV model achieves a balance in network energy consumption and extends the overall network lifespan.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.3
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• pp.173-179
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• 2016

Purpose: This study is to help assist in the management of optical shops by using the importance sequence of optical shop selection attributes, which is related to the consumer's selection method of consumer, and by using the importance sequence of optical shop information sources which is related to a route for optical shop selection. Methods: Customer surveys were conducted from March 10 to March 31, 2015 targeting customers who have visited an optical shop in Seoul and Northern Gyeonggi-do regions. The analys method was descriptive statistics and data were analyzed by utilizing SPSS v.10.0 statistical package program. Results: The highest ranking five attributes among the importance of optical shop selection are "friendliness and politeness of staff", "cleanliness of an optical shop", "quick resolution of customer's complaints by staff", "eyes examination and glasses dispensing skill of staff", "customer's complaints and claims handling". The lowest ranking five attributes among the importance of optical shop selection are "provide free gifts", "scale or size of an optical shop", "opening time and closing time", "convenient parking facilities", "favorable countenance of staff". The two highestr ranking criteria among the importance of optical shop information sources are "previous utilization experience", "recommendation by a relative, a friend and a family etc". The two lowest ranking criteria among the importance of optical shop information sources are "advertisement" and "spatial exterior view of optical shop". Conclusions: It is shown that the important thing in management of an optical shop is an inner caliber like ability of ophthalmic optician, interaction with customers, and previous utilization experience rather than external factors like advertisement, exterior view, and bonus gift.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.445-455
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• 2014

Purpose: By investigating the characteristics of the students ophthalmic optics under bachelor's degree course in academic credit bank system, this study aimed to utilize this survey as a basic material for the operation and the improvement of academic credit bank system as the continued education for opticians. Methods: A questionnaire survey for the characteristics of the students was conducted on 98 bachelors who registered in the academic credit bank system and an analysis was made out of the result. Results: As the purpose of selecting the academic credit bank system, acquisition of bachelor's degree took the major portion (51.0%); for information route, school or superior at work took the major portion (33.7%); and for educational institution, alma mater took the major portion (31.6%). Family cooperation (72.4%) to the students in the academic credit bank system was higher than workplace cooperation (46.9%) or social cooperation (39.8%). For the time required for the bachelor's degree course in the academic credit bank system, 2 semesters (55.6%) took the major portion, and 38.9% for entering graduate school and 5.6% for university transfer. The result showed a significant difference in the information route for the academic credit bank system (p<.05), selection criteria for educational institution (p<.05) and workplace cooperation (p<.01) depending on the age. It showed a significant difference in the selection purpose for the academic credit bank system (p<.01), average attendance day (p<.05), workplace cooperation (p<.01) and difficulties (p<.01) depending on working place. It showed a significant difference in the selection criteria for educational institution (p<.01) and family cooperation (p<.05) depending on the academic system of their alma mater. It showed a significant difference in the information route (p<.05), the selection criteria for educational institution (p<.01) and workplace cooperation (p<.05). Conclusions: It is necessary for optometrists to study and pay more attention to continuing education, and the operation and support for the academic credit bank system should be made in consideration of the characteristics of students.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.1-12
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• 2017

The Seoul metropolitan transportation card's high value lies in its recording of total population movements of the public transit system. In case of recorded information on transit by bus, even though route information utilized by each passenger is accurate, the lack of passenger transfer information of the urban railway makes it difficult to estimate correct routes taken by each passenger. Therefore, pinpointing passenger path selection patterns arising in the metropolitan railway network and using this as part of a path movement estimation model is essential. This research seeks to determine that features of passenger movement routes in the urban railway system is comprised of M-similar routes with increasing number of transfer reflected as additional costs. In order to construct the path finding conditions, an M-similar route searching method is proposed, embedded with non additive path cost which appears through inclusion of the stepwise transportation parameter. As well, sensitivity of the M-similar route method based on transportation card records is evaluated and a stochastic trip assignment model using M-similar path finding is constructed. From these, link trip and transfer trip results between lines of the Seoul metropolitan railway are presented.

• Journal of the Society of Disaster Information
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• v.16 no.1
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• pp.96-110
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• 2020

Recently, due to global warming, it is easily exposed to various disasters such as fire, flood, and earthquake. In particular, large-scale disasters have continuously been occurring in crowded areas such as traditional markets, facilities for the elderly and children, and public facilities where various people stay. Purpose: This study aims to detect a fire occurred in crowded facilities early in the event to analyze and provide an optimal evacuation route using big data and advanced technology. Method: The researchers propose a new algorithm through context-aware 3D object model technology and A* algorithm optimization and propose a scenario-based optimal evacuation route selection technique. Result: Using the HPA* E algorithm, the evacuation simulation in the event of a fire was reproduced as a 3D model and the optimal evacuation route and evacuation time were calculated for each scenario. Conclusion: It is expected to reduce fatalities and injuries through the evacuation induction technique that enables evacuation of the building in the shortest path by analyzing in real-time via fire detection sensors that detects the temperature, flame, and smoke.