• Journal of Communications and Networks
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• v.17 no.2
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• pp.100-109
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• 2015

Mobile phone carriers face challenges from three synergistic dimensions: Wireless, social, and mobile. Despite significant advances that have been made about social networks and human mobility, respectively, our knowledge about the interplay between two layers remains largely limited, partly due to the difficulty in obtaining large-scale datasets that could offer at the same time social and mobile information across a substantial population over an extended period of time. In this paper, we take advantage of a massive, longitudinal mobile phone dataset that consists of human mobility and social network information simultaneously, allowing us to explore the impact of human mobility patterns on the underlying social network. We find that human mobility plays an important role in shaping both local and global structural properties of social network. In contrast to the lack of scale in social networks and human movements, we discovered a characteristic distance in physical space between 10 and 20 km that impacts both local clustering and modular structure in social network. We also find a surprising distinction in trajectory overlap that segments social ties into two categories. Our results are of fundamental relevance to quantitative studies of human behavior, and could serve as the basis of anchoring potential theoretical models of human behavior and building and developing new applications using social and mobile technologies.

• ETRI Journal
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• v.44 no.6
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• pp.936-944
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• 2022

The mobile network allows redundant transmission via disjoint paths to support high-reliability communication (e.g., ultrareliable and low-latency communications [URLLC]). Although redundant transmission can improve communication reliability, it also increases network costs (e.g., traffic and control overhead). In this study, we propose a reliability-guaranteed multipath allocation algorithm (RG-MAA) that allocates appropriate paths by considering the path setup time and dynamicity of the reliability paths. We develop an optimization problem using a constrained Markov decision process (CMDP) to minimize network costs while ensuring the required communication reliability. The evaluation results show that RG-MAA can reduce network costs by up to 30% compared with the scheme that uses all possible paths while ensuring the required communication reliability.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.66-75
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• 2007

The traditional centralized network management method using the SNMP has problems, such as, increase of communication traffic and severe bottleneck phenomena at the specific manager-node caused by a frequent polling mechanism. Several mobile agent based network management methods have been studied to solve and overcome these problem. However, in these mobile agent based methods, as the number of nodes to be managed is increased, the mobile data are increased accumulatively and the effectiveness of the network management is decreased. In this paper, we propose the split management method by using mobile agents to handle these problems. In our method, the nodes are divided into groups to be handled by separate mobile agents. Each mobile agent visits its own nodes and gets management information from them. We demonstrate the effectiveness of our proposed method using experimental results.

• Journal of Korea Multimedia Society
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• v.11 no.10
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• pp.1385-1391
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• 2008

The network-based IP mobility solution - Proxy MIPv6 provides a mobile node with local mobility support without requiring MIPv6 functionality of the mobile node by using two principle functional entities, LMA (Local Mobility Anchor) and MAG (Mobile Access Gateway) located in a Proxy MIPv6 domain. Yet, in case that a mobile node moves into a mobile network located in the domain, the mobile node can't receive the local mobility support any more because it can't communicate with the MAG. This paper proposes a scheme to support nested network mobility in a Proxy MIPv6 domain by adding MAG functionality to a mobile router in the mobile network and evaluates the performance of the proposed scheme. Performance analysis shows that the proposed scheme can increase the performance of handover delay, signaling costs, and packet loss ratio.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.335-338
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• 2004

In this paper, we present a perspective of the next generation mobile communication services and its characteristics. As a preliminary research work on the next generation mobile communications and services, we exploit the next generation mobile services [1]. We define the next generation mobile services as strata of services consisting of three different service levels, the service areas, the service functionalities, and the service technologies. We derive these service levels by means of the scenario based analysis. Finally, we propose a conceptual network architecture that can support the next generation mobile services by placing network functions and service elements within the network.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.2
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• pp.35-46
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• 2013

As a rapid increase of mobile network usage, many studies on solution for network traffic's demand problem have been done. Especially network environment measurement area provides basis for solving network traffic's demand problem by finding causes of problems through accurate network analysis. However, as increase of demand for smartphone, we should consider effects of mobile platform's property measuring mobile network. In this paper, we design a network traffic measurement system considering mobile platform. Through the information from packets, this system calculates packet transmission delay and throughput. We minimize computation cost required for a mobile device that is a client in this system. When fully using network resources, we found that Wi-Fi has shorter transmission delay, higher maximum throughput and lower loss rate than 3G, Android has shorter transmission delay and higher maximum throughput than iOS, and UDP has longer transmission delay and higher maximum throughput through this system.

• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.117-124
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• 2010

Appling centralized network management architecture SNMP(Simple Network Management Protocol) to wireless networks causes the network overhead, NAT(Network Address Translation) problem on AP, and performance degradation of mobile nodes. In this paper, we propose an integrated management scheme for wired and wireless networks using mobile agents in order to solve above problems. In our proposed scheme, SNMP is applied to manage wired networks and MAs of SNMP are implemented in APs or wireless nodes to manage wireless networks. In addition, we propose a method to reduce the redundant OID information within SNMP response messages. Through the analysis, we show that our proposal resolves the given problems and reduces the processing delay of the wireless nodes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.649-651
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• 2014

The Digital Living Network Alliance (DLNA) standard enables easy sharing of multimedia contents in the home network environment. However, with the proliferation of mobile computing devices such as smartphones and tablets, the need for media sharing to expand beyond the boundaries of the home network arose. In this paper, a method for accessing DLNA based home network from the mobile environment is proposed. The proposed method uses mobile Virtual Private Network (VPN), and enables easy access to the resources in the home network from the wireless mobile environment.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.313-317
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• 2005

The network ingress filtering is a simple and efficient method for preventing IP source spoofing of fixed nodes. Since mobile hosts cannot communicate with its correspondent nodes if the network ingress filtering is configured in mobile IPv4 network, reverse tunneling was considered as a method for avoiding network ingress filtering. But, unfortunately this method does not solve IP source spoofing of mobile nodes. In this paper, we propose a simple and efficient method for preventing IP source spoofing of mobile nodes assuming that only the mobile hosts connected to foreign agents and the network that foreign agent manages is small.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.411-413
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• 2010

Now, smart phone markets are grows quickly. So it is needed research of CDN(Contents Delivery Network) technology for contents transmission in mobile networks. Especially the services of smart phone are focused on open platform model. So P2P(Peer to Peer) protocols will be used for mobile network because it is a distributed network architecture composed of participants that make a portion of their resources directly available to other network participants, without the need for a central server. Current research of P2P protocols for mobile network are not activated. The reason is appropriate in the mobile P2P network simulation environment, since it is not provided. So, in this paper we design a mobile P2P simulation system for CDN based on mobile P2P.