• 대한전자공학회논문지TC
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• 제40권7호
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• pp.261-272
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• 2003

Ethernet PON(Passive Optical Network)은 최근 활발하게 연구되고 있는 경제적이고 효율적인 가입자망이다. 차세대 가입자망인 Ethernet PON의 MAC(Media Access Control) 프로토콜은 TDMA(Time Division Multiple Access)방식을 기본으로 하며, QoS(Qualify of Service)를 보장해야 하는 전용회선(Leased Line) 가입자에 적합한 고정 할당 방식과 LAN/MAN의 최선형(Best Effort) 방식에 적합한 동적 할당 방식으로 나눌 수 있다. 본 논문에서는 이들 프로토콜의 성능을 분석하기 위하여 OPNET 시뮬레이션 도구를 이용해 Ethernet PON 모델을 설계한다. 설계된 모델에 대한 단대단 Ethernet 지연(end-to-end Ethernet delay), 큐잉 지연(queuing delay), 처리(throughput)과 사용률(utilization) 분석을 통해서 MAC 프로토콜을 검증하고, 하나의 OLT(Optical Line Terminal)가 수용할 수 있는 최적의 ONU(Optical Network Unit) 개수를 산정한다. 또한, 적정한 ONU의 버퍼 크기를 제안하여 Ethernet PON의 망 효율을 극대화하는 방안을 제시한다.

• 한국산학기술학회논문지
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• 제16권5호
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• pp.3455-3461
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• 2015

지하철에서는 주로 LTE와 Wi-Fi를 통하여 급증하는 무선데이터서비스를 제공하고 있다. 승객의 이동에 따라 이용객 수가 급변하는 특성을 가지고 있으며, LTE는 사용자가 증가해도 안정적인 서비스 제공이 가능한 반면에 Wi-Fi는 이용객이 증가하면 접속시간이 증가하는 등 성능이 크게 저하되는 현상이 발생한다. 본 논문에서는 Wi-Fi 전송망에 대한 수학적 모델링 및 시뮬레이션을 통하여 이용객 증가에 따른 접속지연 증가 특성을 분석하였으며, 영업운영 중인 지하철 10개 역 구간에서 Wi-Fi 망에의 접속지연 및 손실률을 측정하여 비교하였다. 측정 및 분석 결과는 지하철에서의 LTE와 Wi-Fi 간 데이터 오프로딩 구성에 필요한 접속방법 및 향후 LTE-R 도입시 효율적인 망 구성에 적용할 수 있다.

• 경영과학
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• 제23권2호
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• pp.161-174
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• 2006

In this paper, we consider a network optimization problem arising from the deployment of BcN access network. BcN convergence services requires that access networks satisfy QoS meausres. BcN services have two types of traffics : stream traffic and elastic traffic. Stream traffic uses blocking probability as a QoS measure, while elastic traffic uses delay factor as a QoS measure. Incorporating the QoS requirements, we formulate the problem as a nonlinear mixed-integer Programming model. The Proposed model seeks to find a minimum cost dimensioning solution, while satisfying the QoS requirement. We propose two local search heuristic algorithms for solving the problem, and develop a network design system that implements the developed heuristic algorithms. We demonstrate the computational efficacy of the proposed algorithm by solving a realistic network design problem.

• 한국ITS학회 논문지
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• 제4권1호
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• pp.107-115
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• 2005

For effective IP based service implementation on the wireless network environments, wireless network including the ITS network have to support QoS guaranteed protocol such as a RSVP. RSVP is a resource reservation protocol for Internet environment, and its scalability makes easy to implement RSVP over the various IP transport technologies. But for the If based ITS wireless network environment, RSVP is not suitable, since by its path setup procedure characteristic. In the wireless access network for ITS service, when a mobile node moves to other domain it must perform registration procedure. But the registration procedure is time consuming steps, so if a RSVP session was already established in the previous domain, the RSYP session may be disconnected and the time to re establish a new RSVP session is long enough to cause serious packet loss. In this paper, we propose a pre-path reservation mechanism for applying the RSVP in wireless access networks for ITS. In the pre-path reservation mechanism, the resource reservation procedure occurred during a mobile node's handoff time. An access point in wireless access network performs this procedure when the mobile node attempts handoff The access point executes pre-path reservation procedure as a proxy, since the mobile node does not have IP address until the address allocation procedure is finished in a new domain.

• ETRI Journal
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• 제44권6호
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• pp.1020-1033
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• 2022

In this paper, we propose novel disaggregated memory module (dMM) architecture and memory access control schemes to solve the collision and contention problems of memory disaggregation, reducing the average memory access time to less than 1 ㎲. In the schemes, the distributed scheduler in each dMM determines the order of memory read/write access based on delay-sensitive priority requests in the disaggregated memory access frame (dMAF). We used the memory-intensive first (MIF) algorithm and priority-based MIF (p-MIF) algorithm that prioritize delay-sensitive and/or memory-intensive (MI) traffic over CPU-intensive (CI) traffic. We evaluated the performance of the proposed schemes through simulation using OPNET and hardware implementation. Our results showed that when the offered load was below 0.7 and the payload of dMAF was 256 bytes, the average round trip time (RTT) was the lowest, ~0.676 ㎲. The dMM scheduling algorithms, MIF and p-MIF, achieved delay less than 1 ㎲ for all MI traffic with less than 10% of transmission overhead.

• 한국통신학회논문지
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• 제30권7B호
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• pp.427-432
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• 2005

광대역 멀티미디어의 고품질 서비스를 제공하기 위한 가입자 전송 망 분야의 변화가 요구 되고 있는 요즘, PON에 대한 연구가 이를 실현시키기 위한 방안으로 크게 부각되고 있다. 본 논문에서는 SUCCESS(Stanford University aCCESS : next generation hybrid WDM/TDM optical access network architecture) 구조에서의 WDM-PON을 위한 스케줄링 알고리즘을 제안하고자 한다. 경제적 구현을 실현하기 위해서는 공유되는 자원의 보다 효율적인 할당이 필요하며, 이를 위해 SUCCESS의 구조와 특성에 적절한 효율적인 스케줄링 알고리즘을 제안하고 있으며, 전체 시스템에서의 평균 패킷 지연시간 및 처리량에 대한 성능을 평가, 분석한다.

• 한국인터넷방송통신학회논문지
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• 제10권6호
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• pp.77-84
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• 2010

본 논문은 이동 통신 네트워크에서 기지국과 집중국사이에 설치되어 전송 비용을 줄여줄 수 있는 RAN (Radio Access Network)전송 시스템을 구현하는 것이다. 이 시스템은 여러 세대의 이동 통신 기지국 개별적으로 사용하는 전송 링크를 공유함으로써 전송 링크 수를 감소시켜 줄 수 있고, 지연 시간에 민감하지 않은 트래픽을 분류하여 그 트래픽을 Ethernet/IP 네트워크를 통하여 전달해 줄 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2178-2181
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• 2003

Active networks allow active node’s functionality to be extended dynamically through the use of active extensions. This flexible architecture facilitates the deployment of new network protocols and services. However, the active nature of a network also raises serious safety and security concerns. These concerns must be addressed before active networks can be deployed. In this paper we look at how we can control active extension’s access to different active nodes. Specifically, the authentication between active nodes is very important in this case. We use unique identity each node has for transferring access policies between active nodes. In this paper, we suggest a new method of transferring access policies performing authentications using identities between active nodes.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2003년도 추계학술대회 및 정기총회
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• pp.305-308
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• 2003

It is widely used that a network termination rate is calculated by using a Long Run Incremental Costing model. Interconnection Order issued Ministry of Information and Communication in Korea on December 2002 has declared that termination charges of local, national, payphone, and mobile calls are going to be determined by LRIC costing models after 2004. There are lots of preceding researches on a fixed network costing model for applying to LRIC method but on a mobile network not pretty much of them. Besides, Most important basis of current calculation models for termination charges are access costs to connect subscribers to network such as a local loop. In this paper, we look into being of access costs in mobile network and show the applicable standards for cost allocation of access costs in implementing LRIC costing model.

• 경영과학
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• 제27권3호
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• pp.1-14
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• 2010

In this paper we study the access network design problem in Universal Mobile Telecommunication Systems (UMTS) networks. Given the location of radio base stations (node-Bs), their traffic demands, and the candidate facility centers for locating radio network controllers (RNCs), the problem is to determine the configuration of access network, including the number and location of facility centers, the number of RNCs in each facility center, and the links between RNCs and node-Bs, with the objective being to design such a network at the minimum cost. We provide a mathematical formulation of the problem with constraints on RNC and node-B capacities, along with a lower bounding method. We develop a heuristic algorithm with two different initial solution methods designed to strengthen the solution quality. The computational efficacy of their procedures is then demonstrated on a number of test problems.