• Management Science and Financial Engineering
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• v.9 no.1
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• pp.29-49
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• 2003

This paper develops channel reallocation methodologies for survival transmission networks, Any failure on a high-speed telecommunication network needs to be restored rapidly and a channel real-location methodology has an important role for the fast restoration. This paper considers the channel reallocation problems under a line restoration with distributed control, where the line restoration restores the failed channels by rerouting the channels along the two alternative routes. The objective is to determine the optimal number of rerouting channels on the alternative rerouting paths of a given transmission network, where the optimality criteria are the first, the last and the mean restoration times. For each criterion, the problem is formulated as a mixed integer programming and the optimal channel reallocation algorithm is suggested based upon the characterization of the optimal solution.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.11
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• pp.879-894
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• 2013

Recently, due to a explosive growth in the mobile Internet traffic, the problem of excessive data traffic handling on core network and thus scalability problem have been magnified in 3GPP LTE/SAE networks. Current LTE/SAE network based on the central P-GW (PDN Gateway) used as mobility anchor cannot deal with such demand for exponentially increasing mobile Internet traffic. In this paper, we propose a new LTE/SAE network architecture supporting distributed P-GWs and corresponding distributed mobility management to solve these problems. For this, in addition to the deployment of such distributed P-GWs, we propose a dynamic and distributed mobility management by distributing MMEs (Mobility Management Entities) which dynamically manages the location information of a UE's PDN connection, and also propose a handover procedure of such PDN connections by using the proposed distributed P-GWs and MMEs. The performance of the proposed dynamic and distributed LTE/SAE network system is compared with the current LTE/SAE network system in terms of handover latency and network throughput.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.4
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• pp.65-80
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• 2012

Mobile IP is a simple and scalable global mobility solution. However, it may cause excessive signaling traffic and long signaling delay. So MN (Mobile Node) to the home network in order to reduce the number of location update signaling is necessary to reduce the delay. In this paper, the signaling overhead to be distributed evenly on the boundary of the regional network, each MN's dynamic mobility and traffic load is adjusted according to the PMIPv6 (Proxy Mobile IPv6) networks in the proposed dynamic regional mobility management scheme (dMMS). Each user in a distributed network system that offers the least amount of signaling traffic is tailored to the optimized system configuration. Signaling cost function in order to propose a new discrete analytical model is proposed, MN's mobility and packet arrival patterns. Location update and packet delivery costs to calculate the total average, the optimized area to determine the size of the network is proposed. The results of mathematical analysis, the proposed technique dMMS in terms of reducing the cost of the entire signaling were found to be excellent performance.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.976-976
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• 2012

The applicability of a distributed rainfall-runoff model for large river basin flood forecasts is analyzed by applying the model to the Nakdong River basin. The spatially explicit hydrologic model was constructed and calibrated by the several storm events. The assimilation of the large scale Nakdong River basin were conducted by calibrating the sub-basin channel outflow, dam discharge in the basin rainfall-runoff model. The applicability of automatic and semi-automatic calibration methods was analyzed for real time calibrations. Further an ensemble distributed rainfall runoff model has been developed to measure the runoff hydrograph generated for any temporally-spatially varied rainfall events, also the runoff of basin can be forecast at any location as well. The results of distributed rainfall-runoff model are very useful for flood managements on the large scale basins. That offer facile, realistic management method for the avoiding the potential flooding impacts and provide a reference for the construct and developing of flood control facilities.

• Journal of the military operations research society of Korea
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• v.22 no.2
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• pp.73-89
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• 1996

This paper suggests the new IP, SIMIP(Simple Mobile IP), which supports a continuous mobility between a static host and a mobile host in the static TCP/IP LAN environment where mobile hosts are overlayed with cells. For designing a mobile protocol, routing optimization is very important, and it is directly related to the management mechanism of a mobile host's location information. When the mobile hosts' location information are centralized, the network has high risk when a centralized device fails. On the other hand, when they are distributed, the above problems are solved. But it requires complicated techniques in order to search the encapsulated addresses. SIMP centralizes mobile hosts' location information, minimizes the risk by automatically substituting the failed default mobile router with one of the multiple general mobile routers, and supports the optimal routing path through "default mobile router path alternation" Then since SIMIP isn't reasonable the operations informations to the chief in military operations room.ions room.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.226-228
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• 2003

최근에 무선 인터넷과 이동 컴퓨팅 기술이 발전하고, 휴대 전화와 PDA 같은 이동 단말기가 보편화됨에 따라 사용자의 위치정보를 활용한 위치 기반 서비스(LBS: Location Based Services)가 가능하게 되었다. 위치 기반 서비스를 제공하기 위해서는 대용량의 위치 데이타를 신속하게 처리하고 관리하기 위한 시스템이 필요하다. 이에 본 논문에서는 위치 데이타를 효과적으로 분산 저장 및 검색할 수 있는 이동 객체를 위한 분산 위치 저장 컴포넌트를 구현하고 그 성능을 평가하였다. 분산 위치 저장 컴포넌트는 위치 데이타를 저장하고 검색하는 미들웨어, 분산된 미들웨어의 정보를 관리하는 서버 관리자, 빠른 검색을 위해 위치 데이타의 인덱스 정보를 관리하며 검색할 서버의 정보를 반환하는 연결 관리자, 서버의 디스크 상태를 확인하고 디스크 사용을 관리하는 디스크 관리자, 그리고 클라이언트로 구성된다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.6
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• pp.1-16
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• 2012

In this paper, we propose a cost-effective location and service management scheme in LTE (Long Term Evolution) networks, which a per-user service proxy is created to serve as a gateway between the mobile user and all client-server applications engaged by the mobile user. The service proxy is always co-located with the mobile user's location database such that whenever the MU's location database moves during a location hand-off, a service hand-off also ensues to co-locate the service proxy with the location database. This allows the proxy to know the location of the mobile user all the time to reduce the network communication cost for service delivery. We analyze four integrated location and service management schemes. Our results show that the centralized scheme performs the best when the mobile user's SMR (service to mobility ratio) is low and ${\upsilon}$(session to mobility ratio) is high, while the fully distributed scheme performs the best when both SMR and ${\upsilon}$ are high. In all other conditions, the dynamic anchor scheme is the best except when the service context transfer cost is high under which the static anchor scheme performs the best. Through analytical results, we demonstrate that different users with vastly different mobility and service patterns should adopt different integrated location and service management methods to optimize system performance.

• Journal of KIISE:Information Networking
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• v.27 no.1
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• pp.30-38
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• 2000

In distributed HLR environment, the pointer forwarding with distributed HLR(Pointer Forwarding Scheme) has been proposed for eliminating the cost of updating multiple HLRs. In Pointer Forwarding Scheme, the find cost can be changed according to from which HLR a call originates. If a user changes PCS registration areas frequently, but receives calls relatively infrequently, and call for such a user originates from any other HLRs than the recently updated HLR, many VLRs should be traversed in order to find that user. In this paper, location tracking with jumping pointer in distributed HLR(Jumping Pointer Scheme) is proposed. The jumping pointer can be connected between the recently updated VLR and the VLR in which the mobile host currently resides. In case of call delivery, the mobile host can be found sooner by using the jumping pointer. In terms of 'find' cost, Jumping Pointer scheme improves about 17% over Forwarding Pointer scheme. Otherwise, Jumping Pointer scheme takes additional update charge in order to manage the jumping pointer. However the total costs of 'find' cost and 'update' cost for Jumping Pointer scheme are cheaper than them for Forwarding Pointer scheme when call-to-mobility ratio is smaller.

• The KIPS Transactions:PartA
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• v.15A no.2
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• pp.101-110
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• 2008

Ubiquitous computing has extended the computer system into the whole physical space and has ushered the emergence of more dynamic distributed systems. This environment require unique QoS parameters for various devices, resources and user requirements. In this paper, we propose a new hybrid QoS management model which defines a static-dynamic QoS parameter that is more appropriate to the ubiquitous computing environment. This model consists of the QoS Control Management Module(QoS CMM) in the client side and the Resource QoS Management Module (RQoS MM) in the server side. The RQoS MM deals with the static QoS parameters and the whole QoS control of the distributed control(QoS CMM) in order to minimize server load in cases of multiple communication. Finally, we present the experimental result of our location based application using a graphical user interface that shows the multimedia service execution of selected client device types such as desktop PC, notebook and PDA.

• Journal of Korea Spatial Information System Society
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• v.10 no.3
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• pp.79-91
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• 2008

Recently, with highly Interest In Location-Based Service(LBS) utilizing location data of moving objects, the GALIS(Gracefully Aging Location Information System) which is a cluster-based distributed computing architecture was proposed as a more efficient location management system of moving objects. In the SLDS(Short-term location Data Subsystem) which Is a subsystem of the GALIS, since the SDP(Short-term Data Processor) Master transmits current location data and queries to every SDP Worker, the SDP Master reassembles and sends query results produced by SDP Workers to the client. However, the services are suspended during the SDP Master under failure and the response time to the client is increased if the load is concentrated on the SDP Master. Therefore, in this paper, the extended SLDS was designed and implemented to solve these problems. Though one SDP Master is under failure, the other can provide the services continually, and so the extended SLDS can guarantee the high reliability of the SLDS. The extended SLDS also can reduce the response time to the client by enabling two SDP Masters to perform the distributed query processing. Finally, we proved high reliability and high availability of the extended SLDS by implementing the current location data storage, query processing, and failure takeover scenarios. We also verified that the extended SLDS is more efficient than the original SLDS through the query processing performance evaluation.