• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.1A
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• pp.59-66
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• 2008

This paper presents a spectrum sharing and allocation problem in multiple network operators(NOs). Most of previous works as to dynamic spectrum allocation(DSA) schemes have presented the DSA gain achieved by utilizing the time or regional variations in traffic demand between multi-network operators(NOs). In this paper, we introduce the functionalities required for the entities related with the spectrum sharing and allocation and propose a spectrum allocation algorithm while considering the long-term priority(or fairness) between NOs, the prioritybetween multiple class services, and the urgent bandwidth request. It was shown that the proposed algorithm with priorities between multiple class services could sustain better satisfaction ratio(SR) than the fixed allocation schemes or one without priority under different traffic patterns. Therefore, we conclude that the proposed DSA with priorities between multiple class services and network operators could provide the fairness between service classes of network operators and effective negotiation procedure for urgent bandwidth request by users.

• Journal of IKEEE
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• v.7 no.2 s.13
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• pp.181-187
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• 2003

In high speed packet switching network, packet service by priority scheme prefer to QoS. Efficient packet service according to the priority scheme in high speed packet switch is a key point. Therefore development of priority service algorithm in the packet switch is very important. In this paper, we proposed W-iSLIP algorithm that service time take queue length into consideration and compared the proposed W-iSLIP algorithm to other previous proposed algorithm through simulation. Simulation results show 2.6% performance elevation in average delay, and 34.6% performance elevation in priority service.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.103-112
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• 2006

Priority-based network service has been widely adopted for the Internet traffic management in the context of IETF differentiated services, and computing optimal prices for such priority-based service is the key topic in many pricing literature. While the equilibrium analysis has been commonly used to this end, many have criticized the validity of the underlying assumption of equilibrium analysis that user utility functions are precisely known. In this paper, we propose a solution for bridging the gap between the existing theoretical work on optimal pricing and the unavailability of precise user utility information in real networks. In the proposed method, the service provider obtains more and more accurate estimates of user utility functions from the initial imprecise knowledge by iteratively changing the price of service levels and observing the users' decisions under the changed price. Our contribution is two-fold. First, we have developed a general principle for estimating the user utility functions. Second, we have developed a novel method for setting the prices that can optimize the extraction of the knowledge about user utility functions. The extensive simulation results demonstrate the effectiveness of our method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.9B
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• pp.598-603
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• 2007

In this paper we propose a QMAC to support QoS(Quality of Service) and to enhance the transmission throughput in Wireless Sensor Networks(WSNs). In the proposed QMAC, sender nodes send transmission request packets with QoS requirements to the receivers node using CSMA/CA MAC protocol. And the receiver node assigns slots according to the packet priority, network topology, and the amount of traffics using TDMA. Using QMAC we get the enhanced throughput and QoS support by lowering the duplicated slot assignment.

• Journal of KIISE:Information Networking
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• v.33 no.2
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• pp.183-192
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• 2006

This paper analyzes the price-selection problem under priority-based scheduling for QoS (Quality of Service) network services, i.e., how to determine the price associated with each service level. In particular, we focus on the problems with the pricing mechanism based on equilibrium analysis. We claim that the assumptions needed to produce equilibrium nay not hold in some important environments. Specifically, (a) the individual user's impact on the system is not infinitesimal and (b) users do not always have up-to-date global system-status knowledge crucial for optimal user decisions required for equilibrium. These may make the equilibrium models inaccurate in realistic environments. We examine the accuracy of some existing equilibrium methods by using a dynamic model that we have developed for system behavior analysis. The analysis indicates that equilibrium methods fail to model accurately the system behavior in some realistic environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.131-134
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• 2005

This paper describes the efficient peer-to-peer migration method of Grid service agent on the mobile agent based P-Grid. The migration mechanism for transmitting service agent upon the service request is based on the peer's logic network topology. The network topologies that this system uses are organized as star topology, ring topology and tree topology, and agents are migrated by the master/slave method and serial/parallel method. The migration method of services is chosen based on the execution range and characteristic of the requested service. Also, the entire execution time of service is affected by the performance of peer that is a part of network topology, and the migration order, Therefore, the system monitors the performance of peers, and determines the migration priority based on analyzing and learning history. The system can reduce service execution time efficiently with decisions of migration method for service agent and priority of peers.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2835-2842
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• 2013

In this paper, service differentiation scheme using optical buffer that is reduced in size with slow-light technology in optical burst switching networks is presented. In suggested scheme, each outport has buffer to store high-class burst only in case that all its wavelengths are occupied. When all wavelengths are being used, a new arriving high-class burst goes into the buffer and waits until a burst is serviced. As soon as a burst is serviced with a wavelength, the high-class burst at buffer is allocated to the free wavelength. In case that low-class burst is arriving under the same situation, it is not stored at the buffer but discarded. An analytical model is derived to analyze the performance of the suggested scheme and compare its performance with the conventional scheme such as preemption and deflection as well as no service differentiations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.8A
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• pp.1428-1436
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• 2001

본 논문에서는 무선 이동 ATM 네트워크에서 무선채널 상태를 고려하면서 가상목적지와 가상소스를 이용한 효율적인 ABR트래픽 흐름제거 기법을 제안한다. ABR서비스는 높은 우선순위를 갖는 실시간 서비스에 의해 사용되지 않는 유휴대역폭을 효율적으로 사용하는 서비스로, 셀손실에 특히 민감하다. ABR서비스는 대역폭의 효율적인 활용으로 기존ATM네트워크에서 널리 사용되고 있으며, 무선 이동ATM네트워크에서도 이러한 ABR서비스의 제공이 중요하다고 하겠다. 기존 ATM네트워크에서는 효율적인 ABR서비스를 위한 흐름제어기법으로서 RM(Resource Management)셀의 피드백을 이용한 전송율기반 폭주제어 기법을 사용하고 있으나, 이 방식을 무선네트워크에 그대로 적용했을 경우, 심각한 대역폭의 낭비를 가져올 수 있다. 따라서 제안된 기법은 무선 이동네트워크에서 RM셀의 전송을 억제하고 ATM스위치에 의해 MT(Movile terminal)의 ACR을 결정하게 하여 기지국을 통해 단말기로 전송하도록 하였다. ABR트래픽은 MT에서 고정호스트로 전송된다고 가정하고 시뮬레이션을 수행하여, 그 성능을 분석하였다. 성능분석 결과, 제안된 기법은 무선네트워크의 대역폭을 낭비하지 않으면서 링크의 혼잡도를 최소화하여 채널상태에 따라 효율적으로 전송율을 조절할 수 있음을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.3
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• pp.479-491
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• 1994

In this paper, we proposed cell priority control with 2-level thresholds, which was considered cell loss and cell delay requirement, in ATM switch with output buffer. Priority control mechanism presented in this paper improved cell loss rate for cell loss censitive cell and cell delay for delay censitive cell. In this mechanism cell loss rate and mean cell delay of cell priority control mechanism were obtained theoretically. The results show that cell loss rate and mean cell delay improvement become better by adjusting two thresholds according to QOS characteristics.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.7B
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• pp.1001-1008
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• 2010

In this paper, we propose the dynamic spectrum allocation (DSA) algorithm using spectrum sharing method considering the long-term priority between NOs and service classes for the maritime communication system environment where a ship locates at either near shore (or land) or off-shore. It was shown that the proposed algorithm using spectrum sharing with priorities could deliver better satisfaction ratio (SR) than the fixed allocation schemes, in the context of provision of required bandwidth (or spectrum) for each users. Therefore, we conclude that the proposed DSA with priorities could apply to the maritime communication environment and exploit the under-used (or unused, idle) spectrum of terrestrial communication networks.