• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4C
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• pp.343-355
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• 2003

Fair bandwidth allocations at routers protect adaptive flows from non-adaptive ones and may simplify end-to end congestion control. However, traditional fair bandwidth allocation mechanisms, like Weighted Fair Queueing and Flow Random Early Drop, maintain state, manage buffera and perform packet scheduling on a per-flow basis. These mechanisms are more complex and less scalable than simple FIFO queueing when they are used in the interi or of a high-speed network. Recently, to overcome the implementation complexity problem and address the scalability and robustness, several fair bandwidth allocation mechanisms without per-flow state in the interior routers are proposed. Core-Stateless Fair Queueing and Rainbow Fair Queuing are approximates fair queueing in the core-stateless networks. In this paper, we proposed simple Layered Fair Queueing (SLFQ), another core-stateless mechanism to approximate fair bandwidth allocation without per-flow state. SLFQ use simple layered scheme for packet labeling and has simpler packet dropping algorithm than other core-stateless fair bandwidth allocation mechanisms. We presente simulations and evaluated the performance of SLFQ in comparison to other schemes. We also discussed other are as to which SLFQ is applicable.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9A
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• pp.888-897
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• 2007

In this paper, we propose an uplink dynamic resource allocation algorithm to increase sector throughput and fairness among users in 802.16e OFDMA TDD system. In uplink, we address the difference between uplink and downlink channel state information in 802.16e OFDMA TDD system. The simulation results show that not only an increment of 10% of sector throughput but higher level of fairness is achieved by round-robin using the FLR and the rate / margin adaptive inner closed-loop power control algorithm. The FLR algorithm determines the number of sub-channels to be allocated to the user according to the user's position. Also, we get 31.8% more sector throughput compared with the round-robin using FLR by FASA algorithm using uplink channel state information. User selection, sub-channel allocation, power allocation algorithms and simulation methodology are mentioned in Part I.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.5A
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• pp.773-778
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• 2001

인터넷이 본격적으로 상업망으로 전화되고 보편화됨에 따라 인터넷 수요가 급격히 증가될 것으로 예상되고 있다. 이에 따른 빠른 전송과 서비스를 만족시키기 위한 포워딩 기술로써 MPLS에 대한 연구가 활발히 진행되고 있다. 본 논문은 MPLS 영역에서 IP 패킷의 성능이 병목 지역에서 레이블된 것과 레이블 되지 않은 패킷에 따라 어떤 성능을 보이는지를 분석하였다. 링크의 대역폭이 병목지역에서 발생된 패킷 발생률보다 더 작을 경우에는 오히려 시간이 지남에 EK라 MPLS 레이블된 경우에 레이블 오버헤드와 빠른 스위칭이 더욱 혼잡을 발생시켜 레이블 되지 않은 IP 패킷보다 성능이 저하되었다. 이러한 현상에 대한 해결책으로 본 논문은 MPLS shim header 부분에 대한 overhead를 레이블 스위칭 할 때 IP 라우팅을 사용하지 않는 동안 사용되지 않는 필드인 IP header의 주소 필드를 이용하는 새로운 MPLS shim header 할당 알고리즘을 제안하였다.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.403-405
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• 2005

광대역통합망(BcN: Broadband convergence Network)은 IT839에서 정의하는 8대 핵심 서비스를 위한 인프라 기술이며, 이들 핵심 서비스들이 요구하는 가장 중요한 사항은 각 서비스에서 요구하는 단말 및 망의 서비스 주소이다. 이러한 주소의 결정은 서비스 성능을 결정하는 가장 기본적인 사항이다. 따라서 BcN에서는 최종적으로 IPv6 주소에 의한 네트워크 구성으로 이들 8대 핵심서비스의 서비스 품질을 보장할 수 있는 망을 구성하고 서비스 사용자의 망 접속 편리성 제공과 향후 새로운 서비스 확장성을 제공하고자 한다. 따라서 본 논문에서는 IPv6 주소를 이용한 망 구성에 있어서 패킷 포워딩에 가장 큰 영향을 미치는 글로벌 라우팅 테이블과 이를 구성하는 BGP 라우팅 프로토콜의 관련 기능을 살펴보고, 이 라우팅 테이블을 가장 효율적으로 구성할 수 있는 주소 할당 방식에 대하여 기술한다.

• Journal of Ubiquitous Convergence Technology
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• v.1 no.1
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• pp.42-46
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• 2007

In this paper, we proposed an efficient short address allocation mechanism for WiBEEM devices using NAA(Next Address Available) algorithm. The proposed addressing mechanism is based upon the NAA information that is delivered over the beacons every time it is transmitted at the beginning of each super-frame. The NAA-based addressing mechanism is not a systematic way of allocating short addresses to newly joining devices and thus tree-routing cannot be supported. However, it has great advantages when U-City core services including U-Parking Lot System or ATIS(Advanced Traveler Information System) services that require high-speed mobility are considered. Moreover, the proposed addressing mechanism can provide significant expandability of the wireless network to various applications and fast device discovery.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.605-605
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• 2006

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.595-597
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• 2003

유럽지역에서의 현재 및 차세대 이동통신의 규격화를 추진하고 있는 3GPP(3$^{rd}$ generation partnership project)의 경우, 부족한 단말의 주소 및 네트워킹의 향상성을 위해 적극적으로 IPv6의 도입을 추진하고 있는 상황이다. 한편 IPv6 자체의 규격은 IETF(Internet Engineering Task Force)에서 진행하고 있는데, 현재 상황의 경우 3GPP에서 IPv6할당의 규격은 IETF의 규격과 완전호환이 되어 있지않아 IETF가 권고안을 마련한 상태이다. 본 논문은 이러한 상태에서 IETF의 권고안을 만족하는 3GPP네트워크에서의 IPv6주소 할당 방식을 제안한다.

• IE interfaces
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• v.13 no.3
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• pp.424-430
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• 2000

Supply chain management (SCM) is an area that has recently received a great deal of attention in the business community. While SCM is relatively new, the idea of coordinated planning is not. During the last decades, many researchers have investigated multi-stage inventory problems. However, only a few papers address the problem of cost-optimal coordination of multi-stage inventory control with respect to service measures. Even published approaches have a shortcoming in dealing with a delivery lead time consisted of a shipping time and a waiting time. Assumed that there is no waiting time, or that the delivery lead time is implicitly compounded of a shipping time and a waiting time, the problem is often simplified into a multi-stage buffer allocation and a single-stage stochastic buffer sizing problem at all installations. This paper presents a simulation-based heuristic algorithm and a comparison with others for the problem that cannot be decomposed into a multi-stage buffer allocation and a single-stage stochastic buffer sizing problem because the waiting time ties together all stages. The comparison shows that the simulation-based heuristic algorithm performs better than other approaches in saving average inventory cost for both Poisson and Normal demands.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.4
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• pp.303-315
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• 2005

In this paper we address a design problem for hub-and-spoke networks and then consider a capacitated hub locations problem with direct shipment (CHLPwD). We determine the location of hubs, the allocation of nodes to hubs, and direct shipment paths in the network, with the objective of minimizing the total cost in the network. In this paper, CHLPwD is formulated as 0-1 integer programming. We develop an evolutionary algorithm here to solve the large sized CHLPwD. To do this, we present the representation and the genetic operators suitable for the problem and propose a heuristic method for the allocation of nodes to hubs. To enhance the search capability, problem-specific information is used in our evolutionary algorithm. The proposed algorithm is compared with the heuristic method in terms of solution quality and computation time. The experimental results show that our algorithm can provide better solutions than the heuristic.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.957-962
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• 2005

Since the nation's currency crisis in 1997. Korea reioined the USD 10.000 per capita income group after collapse of per capita income to USD 6.000 due to the minus GDP growth and sharp hike of exchange rate. It has also been expected for Korea to achieve per capita income of USD 20.000. provided that it maintains $10\%$ export increase rate. $5\%$ nominal GDP growth rate. $3\%$ consumer price index. $2\%$ increase in KRW/USD exchange rate. and $1\%$ net population increase rate. Yet. it should be noted that the nation needs to fulfill the necessity of various SOC infrastructure investment in order to achieve this goal. This paper will address the prospects for the future direction of the national SOC policies through the historical examination of the industrialized nations. such as U.S.A.. U.K.. France. and Japan. with regard to the relationships between economic growth and SOC provision. Some efforts will be made to forecast the optimal budget allocation of the national SOC, in particular, between highway and railway sectors.