• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6B
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• pp.573-587
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• 2003

Due to the growth of mobile communication and the popularization of Internet, it is expected that wired and wireless communication network of the next generation will be integrated and flourished with IP-based. There have been a great deal of research efforts to provide mobile IP service onthe existing lower layer. The location update and the paging scheme is one of the most challenging technical issues for this topic. In this thesis, a paging method based on the distance-based location update scheme is proposed for IP network to support mobility in layer 3. The proposed scheme is implemented and verified with the OPNET.

• Journal of the Korea Society of Computer and Information
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• v.24 no.8
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• pp.67-76
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• 2019

Along with the diversification of digital content services using wired/wireless networks, the market for the construction of base systems is growing rapidly. Cloud computing services are recognized for a reasonable cost of service and superior system operations. Cloud computing is convenient as far as system construction and maintenance are concerned; however, owing to the security risks associated with the system construction of actual cloud computing service, the ICT(Information and Communications Technologies) market is lacking regardless of its many advantages. In this paper, we conducted an experiment on a cloud computing security enhancement model to strengthen the security aspect of cloud computing and provide convenient services to the users. The objective of this study is to provide secure services for system operation and management while providing convenient services to the users. For secure and convenient cloud computing, a single sign-on (SSO) technique and a system access control technique are proposed. For user authentication using SSO, a security level is established for each user to facilitate the access to the system, thereby designing the system in such a manner that the rights to access resources of the accessed system are not abused. Furthermore, using a user authentication ticket, various systems can be accessed without a reauthorization process. Applying the security technique to protect the entire process of requesting, issuing, and using a ticket against external security threats, the proposed technique facilitates secure cloud computing service.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.389-405
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• 2001

In these days, we have increasing demands on the real-time services, especially for the multimedia data transmission in both of wired and wireless environments and thus efficient and stable ways of transmitting realtime data are needs. Although RTP is widely used for internet-based realtime applications, it cannot avoid packet losses, due to the use of UDP stack and its underlying layers. In the case of mobile computing applications, the packet losses are more frequent and consecutive because of the limited bandwidth. In this paper, we first statistically analyze the characteristics of packet losses in the wired and wireless communications, based on Gilbert model, and a new packet recovery scheme for realtime data transmission is presented. To reflect the transmission characteristics of the present network environment, our scheme makes the sender to dynamically adjust the amount of redundant information, using the current packet loss characteristic parameters reported by the receiver. Additionally, we use relatively large and discontinuous offset values, which enables us to recover from both of the random and consecutive packet losses. Due to these characteristics, our scheme is suitable for the mobile computing environment where packet loss rates are relatively high and varies rapidly in a wide range. Since our scheme is based on the analytic model form statistics, it can also be used for other network environments. We have implemented the scheme with Mobile IP and RTP/RTCP protocols to experimentally verify its efficiency.

• Journal of Korea Society of Industrial Information Systems
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• v.16 no.4
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• pp.53-65
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• 2011

As the Information and Communication Technologies continue to advance, some sensitive services (e.g. e-commerce, on-line financial service, and etc.) have spread rapidly. Accordingly, ensuring the safety of the sensitive service itself using personal Information as well as the protection of personal Information Is becoming very important. In addition, with the popularization of smart phone and the universalized use of wireless Internet, many services that have been provided on the basis of the conventional wired network are increasingly propagating to wired and wireless converged network environment. These changes in the network environment requires new paradigm for the pursuit of safe and stable communication. In this paper, we propose seamless and secure service framework that can facilitate a sustainable secure connection between the user terminal and the sensitive service system by using both the personal and network Information. The proposed service framework is capable of isolating the source of authorized use by a third party of the personal Information as far as the user terminal is not lost, although some personal Information is disclosed. Besides, it can provide a seamless and safe service environment even if the access network is changed by relocation of terminals in the heterogeneous mobile network environment.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.536-540
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• 2006

The interest in the service of 3D mobile contents becomes larger due to the technological advance of production and services of mobile contents and the appearance of the exclusive mobile phone for 3D game. Therefore, the researches about the efficient mobile services of large 3D contents are wanted in the circumstances of the narrow bandwidth and the burden of the connection charge of wireless mobile communications. In this paper, we suggest a strategy of caching for looking up and downloading the 3D marine characters efficiently and a system model for mobile service of 3D marine characters. The suggested system is designed for serving efficiently the high-quality 3D characters through the wireless mobile communications using the database on the 3D marine objects of cyber aquarium constructed for the services through the wired internet.

• Journal of the Korea Convergence Society
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• v.9 no.4
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• pp.9-14
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• 2018

Recently, as the internet speed is getting faster, in the cloud environment, the service receiving device is changing from a general PC to a compact device such as a mobile phone or a tablet PC. Since handheld devices such as mobile phones or tablet PCs are often used in wireless rather than wired, there are many problems that personal information may be exposed maliciously from a third party. In this paper, we propose a user privacy protection scheme through a duplicate duplicate key generation process which can safely protect user 's privacy from third party among cloud services being served through various wireless media. The proposed scheme is used to synchronize the duplicated key between the server and the intermediary device, and aims at shortening the time of the authentication process protecting the user 's privacy. In this case, the proposed scheme uses Interleave() function and random number to synchronize the server and the intermediary device, so it can safely prevent the malicious attack of the third party.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6310-6316
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• 2014

The increase in the Internet and smart device users requires high-level network security. Network security consists of Web Firewall, Network Firewall, IPS, DDoS system, UTM (Unified Treat Management), VPN, NAC (Network Access Control), Wireless security, Mobile security, and Virtualization. Most network security solutions running on IPv4, and IPv6 network services are not sufficiently ready. Therefore, in this paper, this study designed and implemented important functions of Network Access Control (NAC), which include IPv6 host detection, isolation, blocking and domain assignment for the IPv6 network. In particular, domain assignment function makes 128 bits IPv6 address management easy. This system was implemented on a KISA IPv6 test-bed using well known devices. Finally, the test result showed that all IPv6 based wired and wireless devices were well-controlled (detection, blocking, isolation and domain assignment).

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.59-75
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• 2006

In this paper, we propose a congestion control scheme to control the congestion due to the mobility of ubiquitous devices on ubiquitous computing environment. Especially, this congestion control scheme provides a reverse congestion avoidance state which can classify between packet error by features of wireless network and packet dropping by congestion. Also, it provides a slow stop state which can minimize bandwidth waste due to congestion control. The proposed congestion control scheme controls more adaptive than existing congestion control schemes. The proposed congestion control scheme is designed based on DCCP(Datagram Congestion Control Protocol) being proposed by IETF(Internet Engineering Task Force) and implemented on the Linux kernel. In simulation results, the proposed congestion control scheme provides good bandwidth throughput in wireless network as well as in wired network.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.23-28
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• 2018

In recent years, activities have become more important in political activities and participation in policies. Therefore, the level of digital informatization can affect the participation in policy in the online environment. In this study, we examined how the policy activities of the disabled have a relationship with the informatization level. To this end, we analyzed the relationship between the level of digital informatization and the level of satisfaction with policy activities based on the results of the digital divide survey of 2017. The results of this study are as follows: First, it shows that the disabled people have a positive relationship with the digital access and policy activity satisfaction levels such as the possession of wired / wireless information devices and Internet accessibility. Second, it is found that digital information capacity level and income level such as PC utilization ability and mobile digital device utilization ability have a positive (+) relationship. Third, as the level of digital information utilization such as wired and mobile Internet usage increased, the level of satisfaction with policy activities also increased positively. This suggests that the government needs various information policy to increase the level of digital informatization of the disabled.

• Journal of Digital Convergence
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• v.17 no.2
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• pp.1-7
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• 2019

Our society is evolving into an aging society. The purpose of this study is to investigate how digital informatization capacity of elderly people, one of the so - called information - neglected people, affects social activities. To this end, we analyzed the relationship between digital informatization level and social activity satisfaction level of old elderly people based on the results of the digital information gap survey in 2017. As a result, it was found that there was a positive relationship between digital access and satisfaction level of social activities, such as whether elderly people have wired / wireless information devices and internet accessibility. Second, it was found that digital information capacity level such as PC usage ability and mobile digital device utilization ability had a positive (+) relationship with only social activities. Third, the level of satisfaction with social activities increased as the level of digital information utilization increased, such as whether they were using wired and mobile Internet. This suggests that the government needs a policy to resolve various information gaps that can enhance the level of digital informatization of elderly people.