• Journal of Convergence Society for SMB
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• v.1 no.1
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• pp.67-73
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• 2011

Handover in high speed mobile communication service, in particulary mobile WiMAX is supported efficiency mobility to 120km/h speed. But, in order to accommodate number of user increment in a cell, wireless network is increment to microcell and picocell by allocate bandwidth and by decrease cell size. handover is occurrent and increment connection failure ratio In this result. IEEE 802.16 standard is support seamless connection through handover optimization scheme. But because authentication process is abbreviate, network weakness is exposure. In this paper, we propose handover scheme for support realtime service as VoIP, Picure communication, Streaming Data Service in order to support partially encryption method. In experiment, proposed scheme is proof which process time is increment 20% more than previous scheme.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.127-134
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• 2017

In this paper, we try to solve the frequency shortage due to the increase of LTE terminals and the traffic jam caused by the inefficient WiFi connection method. The proposed LTE-WIFI Vertical Handover method uses a pre-authentication method of the AP through LTE and a method of controlling the access AP of the terminal using the RADIUS server. Through the simulation, the proposed method shows that the access speed of the AP is improved by about 95% compared to the conventional connection method, and the connection speed is improved by about 18% compared to the conventional method. Providing seamless AP through pre-authentication system and improving wireless network speed through AP access distribution can solve LTE frequency shortage problem and improve wireless network usage satisfaction.

• Journal of Korea Multimedia Society
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• v.23 no.10
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• pp.1258-1269
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• 2020

The IoT(Internet of Things) service provides users with valuable services by collecting and analyzing data using Internet-connected IoT devices. Currently, IoT service platforms are accomplished by using edge computing to reduce the delay time required to collect data from IoT devices. However, if a user moves to another network with IoT device, the connection will be lost and IoT service will be suspended. To solve this problem, we proposes a service that automatically roaming IoT service when IoT device makes move. IoT roaming service provides a device automatic tracking management technique designed to continue receiving IoT services even if users move to other networks. To check if the proposed roaming service was effective, we implemented IoT roaming service and measured the data transfer time while move between networks along with devices while using IoT service. As a result, the average data transfer time was 124.62ms, and the average service interrupt time was 812.12ms. with this result, we can assume that the user could feel service interruption time very shortly and it will not affect the service experience. with IoT roaming service, we expect that it will present a method that stably providing IoT services even if user moves networks.

• Journal of Information Processing Systems
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• v.13 no.2
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• pp.236-255
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• 2017

The rapid growth of smart devices demands an enhanced throughput for network connection sustainability during mobility. However, traditional wireless network architecture suffers from mobility management issues. In order to resolve the traditional mobility management issues, we propose a novel architecture for future wireless access network based on software-defined network (SDN) by using the advantage of network function virtualization (NFV). In this paper, network selection approach (NSA) has been introduced for mobility management that comprises of acquiring the information of the underlying networking devices through the OpenFlow controller, percepts the current network behavior and later the selection of an appropriate action or network. Furthermore, mobility-related scenarios and use cases to analyze the implementation aspects of the proposed architecture are provided. The simulation results confirm that the proposed scenarios have obtained a seamless mobility with enhanced throughput at minimum packet loss as compared to the existing IEEE 802.11 wireless network.

• Journal of Broadcast Engineering
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• v.14 no.1
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• pp.15-27
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• 2009

As various portable digital devices are developed, the space of the TV audience is expanding. We propose a structure of broadcasting control in VOD service in which viewers can resume the viewing of digital broadcasting contents in different devices after they have stopped the viewing to move to another place. Then we design a session and resource management system of VOD for this control. In particular, we design the session management of each consumer and simulate the seamless VOD connection model.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.678-685
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• 2016

The standard high-availability seamless redundancy (HSR) protocol utilizes duplicated frame copies of each sent frame for zero fail over time. This means that even in cases of a node or link failure, the destination node will receive at least one copy of the sent frame, resulting in no network downtime. However, the standard HSR is mostly based on the electrical signal connection inside the node, which leads to the production of considerable latency at each node due to frame processing. Therefore, in a large scale HSR ring network, the accumulated latencies become significant and can often restrict the mission-critical real-time application of HSR. In this paper, we present a novel design for optical HSR (OHSR) that uses beam splitting/combining techniques. The proposed OHSR passes the frames directly to adjacent nodes without frame processing at each node, thereby theoretically generating no latency in any node. Various simulations for network samples, made to validate the OHSR design and its performance, show that the OHSR outperforms the standard HSR.

• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.94-102
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• 2007

Today, packet services for wireless internet is provided by WiBro WLAN 3G, but it is hard to be satisfied seamless connection in each of networks and wide-area service will increase the number of BS(base station) because WiBro and WLAN has been coverage smaller than 3G. that is, communicate which can use continuous and seamless data service is available when user is moving. Therefore, service provider need to integrate network for reducing management expenses. In this paper, we propose advanced handoff algorithm which is considered by 'user demand bandwidth', 'MN(Mobile Node) movement speed' and 'MN service area' and show that simulating result is superior to 'bandwidth allocation', 'QoS(Quality of Service) rate' and 'handoff failure rate'

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.88-96
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• 2001

Future mobile communication networks, which consist of ATM-based B-ISDN backbone networks and wireless ATM networks, will provide u user with broadband connection and QoS service. These network systems need the lossless handoff methods which support user mobility, satisfy ATM features such as ATM cell ordering and no ATM cell duplication and minimize buffer requirement for ATM cell buffering. In this paper we suggest a multicast-based handoff method to supp$\alpha$t lossless connection as well as to minimize buffer overhead. It establishes a dynamic multicast connection between source terminal and wireless member AP (access point)s. When the mobile terminal receives data packet correctly, it notifies the positive acknowledgement of the packet to all member APs. And member APs then release the MT related temporary buffer space for MT's future movement. Therefore member APs can eliminate unnecessary buffer usage and manage the buffer space efficiently. Analysis result shows that our handoff method has better performance in buffer requirement for lossless and seamless connection services over VCT (virtual connection tree) method and other dynamic multicast-based handoff methods.

• Journal of Korea Multimedia Society
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• v.1 no.1
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• pp.120-129
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• 1998

The mobile computing is a new network environment that support s wireless network connection seamless while the portable computer is moving. This environment involves the problem of re-establishing of new network connection. The mobile computing should provide multicasting service, because multicasting is widely-used application service which delivers messages to the members of the groups. In this paper, we proposed 3-tiered mobile multicasting protocol that transfers multicast packets efficiently and reliablely. Also, we analyzed the performance of 3-tiered mobile multicasting protocol comparing with other mechanism. Our protocol is superior to other mechanism in the aspects of the handoff costs and packet delivery costs.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.11
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• pp.35-43
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• 2011

In this paper, we propose a novel architecture for seamless mobility management to provide users with seamless Internet connection when users roam between diverse wireless local area networks (WLANS) controlled by different management entities. There have been many researches in IETF, i.e., MIPv6, HMIPv6, and PMIPv6, to provide the mobility management. However, practically since wireless access points or access routers, which are managed by an individual manager or ISP managers, have different authentication scheme and the supported mobility management, the previous mobility management protocol developed by IETF can not guarantee the quality of service of application services as the mobile node performs the handover. To solve this drawback, we propose the mobility management scheme to provide QoS-guaranteed Internet services during the handover by configurating the wireless networks which is defined by users. More specifically, we present a model, the architecture and an algorithm for user-defined network (UDN) to provide the seamless Internet service. Finally, the performance of the proposed algorithm is evaluated by the network simulation tool.