• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.6260-6268
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• 2015

In LTE-Advanced that different networks coexist, it is considered that it is actually difficult to provide service continuity with a procedural and static control method applied to the existing voice service. This paper suggests Service Self-Organization to support the service continuity effectively based on SON. It means a method in which a subscriber's terminal collects information about its current condition and base station around, and a base station, through the data collected by monitoring inner or adjacent base station, shares related data and converges, controlling service continuity on its own. In other words, as context information of mobile terminal and base station changes, set-up of related functions such as ISHO, cell selection, source allocation, load control, and QoS mapping is adapted; each function fits into the change, exchanges the process of reorganization, and interacts; these actions go toward to satisfy service continuity. Simulation results show that it provides better performances than the conventional one with the measure of resource utilization rate and outage probability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2393-2398
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• 2014

Because each resource in LTE-Advanced system and network's shapes such as bandwidth, error rate change variably, it is judged that it is impossible to control service continuity with procedural, artificial, and static control method applied to the existing voice service. This research suggests a QoS management mechanism to support the service continuity effectively based on policy control. It means a method in which a subscriber's terminal collects information about its current condition and base station around, and a base station, through the data collected by monitoring inner or adjacent base station, shares related data and converges, controlling service continuity on its own.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.581-584
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• 2004

Currently, there are many subscriber access networks: PSTN, ADSL, Cellular Network, IMT200 and so on. To these service providers that provide above network service, it is important that they authenticate and authorize legal subscribers and account for their usage. At present, There exist the several protocols that Support AAA(Authentication, Authorization and Accounting) service : RADIUS, Diameter, TACACS+. Nowadays, RADIUS has used for AAA service widely. It has been extended to support other access network environment. So, we extend RADIUS to support environment of Mobile IPv6. Mobile IPv6 uses IPsec as a security mechanism, basically. But, IPsec is a heavy security technology for small, portable, mobile device. Especially, it is serious at IKE, the subset of IPsec. IKE is a key distribution protocol that distributes the key to the endpoints of IPsec. In t:lis paper, we extend RADIUS to support environment of Mobile IPv6 and simplify the IKE phase of IPsec by AAA system distributing the keys by using its security communication channel. Namely, we propose the key distribution method for IPsec SA establishment between mobile node and home agent. The suggested method was anticipated to be effective at low-power, low computing deyice. Finally, end users feel the faster authentication.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.1
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• pp.69-76
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• 2010

We describe an all-optical circuit which recognizes the header information of packet-by-packet in the access networks based on FTTH. The circuit's operation is confirmed by an experiment in the recognition of 3 and 4 header bits. The output from the header recognition circuit appears in a signal assigned in the time axis according to the header information. The recognition circuit of header for self-routing has a very simple structure using only delay lines and switches. The circuit is expected that it can be constructed of the high reliability and the low cost. Also, the circuit can solve the problems of the power loss and private security which is the weak point of the TDM-PON method by being established a unique transmission line to each subscriber.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.1
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• pp.87-101
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• 2017

As people increasingly rely on mobile networks in modern society, mobile communication security is becoming more and more important. In the Long Term Evolution/System Architecture Evolution (LTE/SAE) architecture, the 3rd Generation Partnership (3GPP) team has also developed the improved Evolved Packet System Authentication and Key Agreement (EPS AKA) protocol based on the 3rd Generation Authentication and Key Agreement (3G AKA) protocol in order to provide mutual authentication and secure communication between the user and the network. Unfortunately, the EPS AKA also has several vulnerabilities such as sending the International Mobile Subscriber Identity (IMSI) in plain text (which leads to disclosure of user identity and further causes location and tracing of the user, Mobility Management Entity (MME) attack), man-in-middle attack, etc. Hence, in this paper, we analyze the EPS AKA protocol and point out its deficiencies and then propose an Efficient and Security Enhanced Authentication and Key agreement (ESE-EPS AKA) protocol based on hybrid of Dynamic Pseudonym Mechanism (DPM) and Public Key Infrastructure (PKI) retaining the original framework and the infrastructure of the LTE network. Then, our evaluation proves that the proposed new ESE-EPS AKA protocol is relatively more efficient, secure and satisfies some of the security requirements such as confidentiality, integrity and authentication.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.56-59
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• 2001

In this paper, unmaned fully automation systems are applied for the CSTR(Continuously Stirred Tank Reactor) and, SBR (Sequencing Batch Reactor) wastewater treatment pilot plant. This plant is constructed in the country side which is little far from a main city. So networks and wireless modules are employed for the data transmission. The SBR plant has a local control and monitoring system which is contained communication parts which consist of one ADSL (Asymmetric Digital Subscriber Line) network and one CDMA (Code Division Multiple Access) module. Remote control and monitoring systems are constructed at a laboratory in a metropolis.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.153-161
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• 2004

An efficient mobility management for mobile stations plays an important role in mobile communication networks. In this paper, we intend to improve the performance of the movement-based location update scheme which is simple to implement and shows good performance. The basic idea used in the proposed location update scheme is to avoid the location update if the mobile subscriber moves around the cell where the last location update was performed. This Is made possible by utilizing the simple movement history information. The performance of the proposed scheme is evaluated and compared with the movement-based location update scheme through simulation. The simulation results show that the proposed location update scheme provides the better performance compared with the movement-based location update scheme by minimizing the unnecessary location updates.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.237-242
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• 2005

In this paper, a fast handoff algorithm between PDSNs in 3GPPx network for a mobile node, is proposed. It introduces a method by which handoff can be performed without reestablishing PPP connection that may occur in the process of performing handoff between PDSNs. When the PDSN recognizes the mobile node moving into its coverage area, it can quickly establish a communication channel with the mobile node based on the already received subscriber information. As a result, handoff is performed without reestablishing PPP. Accordingly, handoff between PDSNs can be performed faster, removing time needed for establishing a PPP session with a terminal and for terminating a previously set up PPP session.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2992-2998
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• 2013

The future mobile communication system can support not only voice but also multimedia applications such as data, image and video. It requires greater resources than the voice-oriented mobile system. We propose user and sub-channel priority based resource allocation for mobile multimedia services in the OFDMA systems. Our method is able to guarantee QoS continuity of realtime services and carry the maximum number of non-realtime subscriber. Simulation is focused on total throughput and blocking rate. The simulation results show that our proposed method provides a better performance than the conventional method.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.1
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• pp.111-119
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• 1998

To predict propagation environments of antenna radiation pattern, it is very important for deceision of service area, selection of the best station location and design of cell etc. By analyzing the propagation prediction model that is varied acceding to the kind of antenna, beam angle, terrain and obstacles, we expect that the economic operating of communication networks, calling quality and service of subscriber will be enhanced. It was measured the fields strength to propose the optimal propargation predicted model of the zone of Seji base station in Naju-city. The simulations of field test are 4 types Hata model, the Egri model, the Carey model and the proposed model. Finally the proposed model are more close agreement with experimental test than other models.