• Journal of Korea Multimedia Society
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• v.9 no.1
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• pp.73-88
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• 2006

With the development of Next Generation convergence Network, the current Internet needs a new network architecture and new session establishment methods, which can support various applications requiring differentiated traffic processing and high quality of service instead of the conventional best-effort service. It is expected that, in next generation network based on All-IP. SIP will play an important role in the session establishment between the end to end user terminals. In this paper, we propose a new network architecture that can provide quality of service based on SIP using the QoS enabled SIP servers and policy servers, and we also propose a new session establishment method that apply the user's demands participating the session establishment when setting up the session using the SIP. Through simulations under various environments, we show the parameter ranges in terms of server capacity and the number of users in access networks to achieve reasonable delay bounds.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.10
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• pp.967-973
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• 2014

WAVE (Wireless Access in Vehicular Environments) communications is the core technology for C-ITS (Cooperative-Intelligent Transportation System) which communicates with the road infrastructure and other vehicles to exchange traffic information and service while driving. In this paper, to analyze the performance degradation according to the distance between WAVE communication terminals, we derived the formulas for the locations of down-fade and up-fade points by using the two-ray ground reflection model, and verified these theoretical results by comparing with those of RSSI (Receiver Signal Strength Indicator) measurements. In addition, to solve the problem of down-fade, we suggested the WAVE communication with the antenna diversity and experimentally confirmed the performance improvement in the highway LOS (Line Of Sight) environments.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.7
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• pp.1140-1147
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• 2022

With the development of digital technology, the marine environment is expected to change rapidly. In the case of autonomous vessels, technology is being developed in many countries, and the international community has begun to discuss ways to operate it. Changes in ships cause changes in the marine traffic environment and urge changes to aids to navigation. This study aims to analyze the cyber security management awareness of VTS personnel to improve the cyber security system for aids to navigation. To this end, the current status of cyber security management was reviewed with a focus on VTS, and a survey was conducted on VTS personnel. The survey analysis used the IPA methodology, and as a result of the analysis, a clear difference was observed in the perception of cybersecurity between those with experience in security and those without experience. In addition, technical measures related to cyber-attack detection and blocking should be implemented with the highest priority. The results of this study can be used as basic data for improving the cyber security management system for aids to navigation.

• Journal of the Society of Disaster Information
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• v.16 no.4
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• pp.682-690
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• 2020

Purpose: This study builds a database by collecting and refining disaster occurrence data and real-time weather and atmospheric data. In conjunction with the public data provided by the API, we propose a service model for the Big Data-based Urban Safety Index. Method: The plan is to provide a way to collect various information related to disaster occurrence by utilizing public data and SNS, and to identify and cope with disaster situations in areas of interest by real-time dashboards. Result: Compared with the prediction model by extracting the characteristics of the local safety index and weather and air relationship by area, the regional safety index in the area of traffic accidents confirmed that there is a significant correlation with weather and atmospheric data. Conclusion: It proposed a system that generates a prediction model for safety index based on machine learning algorithm and displays safety index by sector on a map in areas of interest to users.

• Smart Structures and Systems
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• v.32 no.1
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• pp.9-21
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• 2023

The parameters of civil engineering structures have time-variant characteristics during their service. When extremely large external excitations, such as earthquake excitation to buildings or overweight vehicles to bridges, apply to structures, sudden or gradual damage may be caused. It is crucially necessary to detect the occurrence time and severity of the damage. The unscented Kalman filter (UKF), as one efficient estimator, is usually used to conduct the recursive identification of parameters. However, the conventional UKF algorithm has a weak tracking ability for time-variant structural parameters. To improve the identification ability of time-variant parameters, an adaptive UKF with forgetting factor (AUKF-FF) algorithm, in which the state covariance, innovation covariance and cross covariance are updated simultaneously with the help of the forgetting factor, is proposed. To verify the effectiveness of the method, this paper conducted two case studies as follows: the identification of time-variant parameters of a simply supported bridge when the vehicle passing, and the model updating of a six-story concrete frame structure with field test during the Yangbi earthquake excitation in Yunnan Province, China. The comparison results of the numerical studies show that the proposed method is superior to the conventional UKF algorithm for the time-variant parameter identification in convergence speed, accuracy and adaptability to the sampling frequency. The field test studies demonstrate that the proposed method can provide suggestions for solving practical problems.

• Korean Management Science Review
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• v.23 no.3
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• pp.243-257
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• 2006

ITU-T's NgN(Next generation Network) architecture is expected to offer a new Internet platforms such as QoS(Quality of Service) guaranteed services as it overcame the limitations of the existing best-effort Internet architecture. However, policy development crucial for the NgN framework(e.g., interconnections and billing) is lagging far behind technology development. For example, arguments over network neutrality clearly indicate little understanding of the Internet industry structure where diverse providers including ISP and CP coexist. This study employs a network economics approach to predict how the competitive landscape involving various providers will evolve under the traffic-based billing system under the NgN environment. Applied is the non-cooperative game theory, in particular, Stackelberg's repeated game in order to build and analyze model for competition among those providers. We also studied possible impacts that CPs would have on the competitive landscape if they have an option to replace ISP: i.e., CDN(Content Delivery Network) provider. Lastly, based on the model analysis and experiments, presented are their implications to policy development and tile future prospect.

• Journal of Digital Contents Society
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• v.17 no.4
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• pp.273-278
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• 2016

Disasters are linked with some attributes of modern society in diversity, complexity and unpredictability, so various approach and remedies of them will appease the nation's anxiety upon them. For this reason, in this paper we review the building plans and its application and its application Province pros and cons of intelligent video surveillance analysis system for social security, the future proposed service is the safety of people while performing a comprehensive urban traffic control functions as a video monitoring system for social security and to ensure, to prevent crime and accidents, it is to crack down on criminal offenses in advance expected to protect the property of citizens and public facilities.

• Journal of Internet Computing and Services
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• v.8 no.2
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• pp.55-65
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• 2007

BcN is a high-quality broadband network for multimedia services integrating telecommunication, broadcasting, and Internet seamlessly at anywhere, anytime, and using any device. BcN is Particularly vulnerable to intrusion because it merges various traditional networks, wired, wireless and data networks. Because of this, one of the most important aspects in BcN is security in terms of reliability. So, in this paper, we suggest the sharing mechanism of security data among various service networks on the BcN. This distributed, hierarchical architecture enables BcN to be robust of attacks and failures, controls data traffic going in and out the backbone core through IP edge routers integrated with IDRS. Our proposed anomaly detection scheme on IDRS for BcN service also improves detection rate compared to the previous conventional approaches.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.10
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• pp.34-40
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• 2014

With the economical data service delivery, the packet transport network (PTN) technologies have emerged as an important player in the next-generation transport networks. As the PTN continues to make such considerable progress, it is being challenged by network providers who need rapid and reliable recovery capabilities to guarantee the availability of their services. This paper introduces several fault detection mechanisms for a client signal failure in packet transport networks and proposes a reliable transmission method of IP flows from routers using the combination of Ethernet services. Based on the first fault detection methods, client signal fault is detected within tens or hundreds of milliseconds. It enables the client network devices to perform their own recovery processes within one second. The second mechanism enables failed Ethernet services to be bypassed via other Ethernet services over disjoint paths, so as to contribute on reducing packet loss of IP traffic.

• Journal of Digital Convergence
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• v.12 no.4
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• pp.475-484
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• 2014

This research was about the economic impact and the development plan by analyzing satisfaction and the contributions of Keochang International Festival(KIFT) that visitors recognize. It also sought ways to the development of an KIFT by conducting in-depth interviews with experts. According to the survey of visitors' recognition, KIFT contributed to the regional and the arts development. And it also showed that people recognize the contribution to imaging Keochang as the city of art. In regard to the visitors' satisfaction, they were satisfied generally with the festival and performance, but the satisfaction level was quite low with the traffic, service quality, etc. In respect to the economic impacts, the direct cost effect caused by holding the theater festival was 128,000 thousand won in 2013. Also the annual economic(indirect) impact on the production was 16 billion won, personal income 319,358 thousand won, added-value 7,549,540 thousand won, and taxes 780,733 thousand won.