• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.4
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• pp.684-702
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• 2011

This paper proposes a TDMA-based multichannel medium access control (MAC) protocol for QoS provisioning in mobile ad hoc networks (MANETs) that enables nodes to transmit their packets in distributed channels. The IEEE 802.11 standard supports multichannel operation at the physical (PHY) layer but its MAC protocol is designed only for a single channel. The single channel MAC protocol does not work well in multichannel environment because of the multichannel hidden terminal problem. Our proposed protocol enables nodes to utilize multiple channels by switching channels dynamically, thus increasing network throughput. Although each node of this protocol is equipped with only a single transceiver but it solves the multichannel hidden terminal problem using temporal synchronization. The proposed energy efficient multichannel MAC (EM-MAC) protocol takes the advantage of both multiple channels and TDMA, and achieves aggressive power savings by allowing nodes that are not involved in communications to go into power saving "sleep mode". We consider the problem of providing QoS guarantee to nodes as well as to maintain the most efficient use of scarce bandwidth resources. Our scheme improves network throughput and lifetime significantly, especially when the network is highly congested. The simulation results show that our proposed scheme successfully exploits multiple channels and significantly improves network performance by providing QoS guarantee in MANETs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.302-308
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• 2013

Internet is becoming more common with increasing cloud services have been spreading rapidly. A SLA is agreements between service providers and customers of service providers is how to ensure quality of service. SLA in cloud computing environments from the perspective of the IT service providers to customer satisfaction increase for service quality, it will need to differentiate between competing carriers QoS guarantees with SLA is a very important factor. However, the study of SLA in the cloud is staying in its infancy. In this paper, SLA indices for cloud services defining and use them SLA Management System for QoS guarantee has been implemented. The proposed system using monitoring-based migration policy an open source-based cloud computing platform which Cluster Nodes load distribution of virtual machines assigned to their availability, response time, throughput analysis of what affects and is compared with existing cloud.

• Journal of Navigation and Port Research
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• v.30 no.3 s.109
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• pp.211-217
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• 2006

In recent years, the pileup of world ports is deepening as time goes by due to China effect and continuous increase of world trade volume. The shipping companies try to reduce their shipping cost by using mega vessels in the ports. Shipping companies consider most of the ships turnaround time as a critical factor when selecting a calling port for reducing cost. This paper will suggest how we can guarantee terminal QoS like ship waiting time ratio and ship residing time applying RFID(Radio Frequence IDentification) technology, raising up rapidly as a fundamental solution of new growing industry to port information system. Also, lead time of whole port logistics can be decreased for reduction of loading & discharging time and result from productivity improvement of Twin-lift G/C(Gantry Crane} as applying RFID technology to terminal operation. The purpose of this paper suggests that the new business model of U-Port which port QoS can be guaranteed using RFID based RTLS technology.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11B
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• pp.1178-1190
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• 2009

IEEE 802.11e proposed by IEEE 802.11 working group to guarantee QoS has contention based EDCA and contention free based HCCA. HCCA, a centralized polling based mechanism of 802.11e, needs a scheduling algorithm to allocate the network resource efficiently. The existing standard scheduler, however, is inefficient to support for QoS guarantee for real-time service having VBR traffic. To efficiently assign resource for VBR traffic, in this paper, we propose TXOP algorithm based on dual leaky bucket using average resource allocation and peak resource allocation. The minimum TXOP of each station is obtained by using statistical approach to maximize number of stations of which performance satisfy QoS target. Simulation results show that the proposed algorithm has much higher performance compared with reference scheduler in terms of throughput and delay.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8B
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• pp.751-759
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• 2009

Due to the advance of WLAN technology, the use of the multimedia service such as the video streaming service has been increased in the home network. However, we need to study the method which decreases the transmission delay and the frame loss rate to provide QoS of the video streaming service. Therefore, this paper proposes an active buffer management mechanism to guarantee QoS of the streaming service in IEEE 802.11e EDCA. The proposed protocol discards the frame in the HoL of the buffer based on the importance of each frame and the virtual transmission delay of frame newly arriving at the buffer. In the simulation results, the proposed algorithm not only decreases the frame loss probability of important I and P frames but also stabilizes the transmission delay. It may increase the QoS of video streaming services.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.119-125
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• 2007

On account of limited resources and diverse topology change. it is difficult to manage MANET and guarantee QoS. In current MANET, QoS grantee is exceedingly significant. However, today's MANET are being concentrately worked on MAC protocols and routing protocols. Thus we proposed a framework for effective management of MANET and supporting QoS using policy based network management paradigm and active network technology. Since this framework employs the policy-based management approach in active network environment, it provides an abstract and autonomous management method to network managers.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.995-998
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• 2005

A task in imprecise computation consists of mandatory part and optional part. The optional part can be executed partially and the quality of service is measured by the amount of the execution. Many paper showed that multimedia systems are good applications of imprecise computation. It is important to guarantee QoS which is a critical factor in multimedia systems. Previous works didn't consider QoS and processor slack were assigned randomly to tasks. This paper presented a systemic slack assignment method according to QoS levels of tasks. A simulation result showed that our method can be a good choice for multimedia systems with QoS requirement.

• Convergence Security Journal
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• v.10 no.3
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• pp.69-75
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• 2010

At present, deterioration in service quality, which caused by increased network traffic from a lot of users in the same network, makes smooth communication service difficult. In this paper, we present policy-based QoS management system for VoIP service in order to supply smooth VoIP service to users. The presented system can guarantee quality of VoIP service even in huge traffic situation, and makes it possible to operate whole network in an efficient manner.

• Journal of Korea Multimedia Society
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• v.11 no.12
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• pp.1730-1738
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• 2008

Quality of Service (QoS) Guarantees grant ways for service providers to establish service differentiation among subscribers. On the other hand, service subscribers are also assured the level of service they paid for. In addition, the efficient level of service quality can be selected according to the subscribers' needs thus ensuring efficient use of available bandwidth. While network utility optimization techniques assure certain QoS metrics, a number of situations exist where some QoS goals are not met. The optimality of the network parameters is not mandatory to guarantee specified QoS levels. This paper proposes a joint data rate and power control scheme that guarantees service contract QoS level to a subscriber using Goal Programming. In using goal programming, this paper focuses on finding the range of feasible solutions as opposed to solving for the optimal. In addition, in case no feasible solution is found, an acceptable compromised solution is solved.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.40.1-40
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• 2001

In this paper, control theoretic approaches are proposed to guarantee QoS (Quality of Series) such as packet delay and packet loss of real-time traffic in high-speed communication network. Characteristics of variable rate real-time traÆc in communication networks are described. The mathematical model describing networks including source and destination nodes are suggested. By a traffic control mechanism, it is shown that worst-case end-to-end transfer delay of traffic can be controlled and packet loss can be prevented. The simulation shows results of delay control and buer level control to raise QoS in realtime traffic.