• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1A
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• pp.24-35
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• 2008

We propose a tree-based integrated network of infrastructure network and mobile ad hoc network to effectively support Mobile IP for mobile ad hoc networks and also proposed a network management protocol for formation and management of the integrated network and a tree-based routing protocol suitable for the integrated network. The integrated network has fixed gateways(IGs) that connect two hybrid networks and the mobile nodes in the network form a small sized trees based on the mobile nodes that are in the communication distance with a IG. A new node joins an arbitrary tree and is registered with its HA and FA along tree path. In addition, the proposed protocol establishes a route efficiently by using the tree information managed in every node. We examined the effectiveness of the tree-based integrated network for some possible network deployment scenarios and compared our routing protocol against the Mobile IP supported AODV protocol.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.237-242
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• 2008

A number of wireless technologies have been implemented, but each technology has its limitation in terms of coverage and bandwidth. WLAN and 3G cellular network has emerged to be a complementary platform for wireless data communications. However, the mobility of roaming terminals in heterogeneous networks poses several risks. To maintain secure communications in universal roaming, the effective authentication must be implemented. The focus of this paper is on analysis of authentication architecture involved in integrated WLAN/3G networks.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.83-88
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• 2010

Recently car navigation systems which have been widely spread and evolved. The systems use various information and techniques such as real time traffic information and augmented reality technique. In order to provide a shortest path with good flow, real-time traffic information provided by DMB is required. Augmented reality technique is also introduced to give a reality to driver by displaying real images captured by camera during driving. However, these operate well when the system receives GPS data normally. Exact information about the positions of vehicles is a base that supports the above function with realities. This paper proposes a model for acquiring exact position of vehicles. When the GPS does not operate normally, the proposed model uses various data which are generated by integrated vehicle networks.

• Journal of Satellite, Information and Communications
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• v.2 no.2
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• pp.85-91
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• 2007

The satellite networks provide global coverage. The integration of terrestrial networks with a satellite network is the most attractive approach to develop a global communication system. The IP Multimedia Subsystem (IMS) is intended to be the system that will merge the internet with the telecom world. A user with a dual-mode terminal can access both the satellite network and terrestrial network. The seamless handoff between two networks and a user's QoS level is the major issue concerning this integration. In this paper, we propose IMS-based satellite/terrestrial integrated network architecture for a global communication system. Based on the proposed architecture, an inter-network handoff and end-to-end soft QoS procedure is discussed. Our proposed soft QoS scheme is also analyzed to calculate the number of rejected calls.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.150-157
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• 2012

Fish communities in river networks provide significant ecosystem services that will likely decline under future land use and climate change. We developed a model that simulates the consequences to multiple populations of one or more fish species-a meta-community-from multiple stressors across a river network. The model is spatially-explicit and age-structured, with three components: habitat suitability; population dynamics, including species interactions; and movement across a spatial network. Although this model is simple, it can form the basis of fisheries assessments and may be incorporated into an integrated modeling system for watershed management and prediction.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.126-137
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• 1994

Performance management of computer networks is intended to improve a given network performance in order for more efficient information exchange between subsystems of an integrated large-scale system. Importance of perfomance management is growing as many functions of the large- scale system depend on the quality of communication services provided by the network. The role of performance management is to manipulate the adjustable protocol parameters on line so that the network can adapt itself to a dynamic environment. This can be divided into two subtasks : performance evaluation to find how changes in protocol parameters affect the network performance and decision making to determine the magnitude and direction of parameter adjustment. This paper is the first part of the two papers focusing on conceptual design, development, and evaluation of performance management for token bus networks. This paper specifically deals with the task of performance evaluation which utilizes the principle of perturbation analysis of discrete event dynamic systems. The developed algorithm can estimate the network performance under a perturbed protocol parameter setting from observations of the network operations under a nominal parameter setting.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.6
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• pp.1016-1021
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• 2008

A number of wireless technologies have been implemented, but each technology has its limitation in terms of coverage and bandwidth. WLAN and 3G cellular network has emerged to be a complementary platform for wireless data communications. However, the mobility of roaming terminals in heterogeneous networks poses several risks. To maintain secure communications in universal roaming, the effective authentication must be implemented. The focus of this paper is on analysis of authentication architecture involved in integrated WLAN/3G networks.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.7 s.349
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• pp.50-59
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• 2006

The new communication paradigm is rapidly shifted from wireless mobile networks to an All-IP(Internet Protocol) network, led by service industry leaders and communication manufacturers. In this paradigm, providing authentication and session keys of a subscriber becomes one of the critical tasks because of IP open accessibility among heterogeneous networks. In this paper, we introduce authentication process procedure of heterogeneous wireless mobile networks and develop so-called IMAS(Integrated Mobile Authentication Server) which can securely inter-work among all mobile networks and support the legacy networks with backward compatibility. Especially, in designing IMAS, mobile authentication inter-working mechanism, key management technique, and other issues to be overcome are presented. We analyze and evaluate the performance of authentication algorithm which creates session key. A simulation environment of IMAS is established, and a performance(TPS; Transaction Per Second) result is analyzed and evaluated. It turned out that IMAS works among heterogeneous wireless mobile networks without compensating efficiency and functionalities of the legacy networks and decrease the entropy of data redundancy and data inconsistency among networks because of the integrity of the distributed Data Base(DB).

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2005.05a
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• pp.267-271
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• 2005

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.2
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• pp.714-727
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• 2015

The hierarchical structure in networks is widely applied in many practical scenarios especially in some emergency cases. In this paper, we focus on a tree network with and without packet loss where one source sends data to n destinations, through m relay nodes employing random linear network coding (RLNC) over a Galois field in parallel transmission systems. We derive closed-form probability expressions of successful decoding at a destination node and at all destination nodes in this multicast scenario. For the convenience of computing, we also propose an upper bound for the failure probability. We then investigate the impact of the major parameters, i.e., the size of finite fields, the number of internal nodes, the number of sink nodes and the channel failure probability, on the decoding performance with simulation results. In addition, numerical results show that, under a fixed exact decoding probability, the required field size can be minimized. When failure decoding probabilities are given, the operation is simple and its complexity is low in a small finite field.