• The Journal of the Korea Contents Association
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• v.9 no.2
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• pp.76-87
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• 2009

The growth of CPU and communication technologies have made an important contribution to the development of the network-based intelligent service robots. Robot software must guarantee the correct execution and safety of the user. To achieve this, it is highly required to research how to guarantee the QoS of the components which organize a robot software. The QoS of robot components aims to execute the component stably by processing the data stream in a correct way. By guaranteeing QoS, we can achieve the intelligence and stability of robots. In this paper, we design and implement the QoS framework to guarantee the QoS of robot components on robot platforms with limited resources. We also measure the response times of QoS requests and present the performance analysis results about it.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.7A
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• pp.611-619
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• 2005

The present paper proposes two different packet scheduling algorithms in the IEEE 802.16e type TDD-OFDMA downlink, which are the weighted fair scheduling(WFS) and the throughput guarantee scheduling(TGS). The performance of proposed scheduling algorithms are compared to some of conventional schedulers such as round robin(RR), proportional fair(PF), fast fair throughput(FFTH), and fair throughput(FH) in terms of service coverage, effective throughput and fairness at 64 kbps and 128 kbps minimum user throughput requirements. For a relatively smaller throughput(64 kbps) requirement, the proposed algorithms provide higher improvement in the number of users per sector within 95$\%$ service coverage while satisfying the lxEV-DV fairness criterion. For a relatively larger throughput(128 kbps) requirement, the proposed algorithms provide higher coverage enhancement while maintaining the same effective aggregate throughput over PF scheduler.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.41 no.6 s.324
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• pp.41-48
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• 2004

In an IP network, various types of traffics are statistically multiplexed to utilize efficiently the network resources. The DiffServ-aware-MPLS supports a wide variety of communication services with different QoS requirements. The DiffServ-aware-MPLS based on QoS architecture had become one of the most promising ways to guarantee QoS MulIti-service IP network. But how to manage IP network with QoS guarantee is still an open issue. In this paper, we propose DiffServ-aware-MPLS buffer management technique using the specified policing, queuing, and scheduling.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.131-145
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• 2004

Mobile IP has been designed only to maintain communications as mobile devices move from a place to a place, so it does not guarantee Quality of Service (QoS). Hierarchical MIPv6 improved QoS somewhat using Mobility Anchor Point(MAP), but QoS guarantee problem still remains. QoS in mobile IP is important to provide multimedia and real-timeapplications services in a mobile environment, and QoS is closely related to handoff delay. Therefore, handoff delay problem is actively studied as a main issue in mobile IP research area to guarantee QoS. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in an active network in order to resolve such a problem, Suggested QoS controlled method and existing handoff method, simulations are carried out with NS-2 for performance evaluation. The results of simulations show an improvement on handoff delay, and consequently the QoS improvement.

• International Commerce and Information Review
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• v.14 no.4
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• pp.339-360
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• 2012

We have more risks in international trade market than in the domestic business market because economic activities are going on with business transactions in different countries. K-sure's Refund Guarantee System is the most important system for Korean Small and Middle Shipbuilding Industries' business, but Korean exporters of Shipbuilding Industries are more interested in export financing through K-sure rather than its financial supporting services. The export insurance becomes more important service for international trade business and it its count as the only one indirect way of supporting export business because export insurance is accepted internationally under the WTO system. Also, it is the only measure that can cover emergency risk, credit risk, exchange risk which cannot be covered by private insurance. As the major risk manager for Korean exporters, the K-sure needs to provide an integrated risk management service for customers. Korean exporters can take more challenges in ever competitive international trade market and we can witness promotion of export in the future which is essential to Korea's economic growth.

• Journal of the Korea Computer Industry Society
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• v.2 no.12
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• pp.1505-1516
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• 2001

The goal of Medical multimedia server is to develop computer hardware and software which would enable electronic access, storage, transmission, and display of patient data and images. Since the current network only provides so called "best-effort" services, it is impossible to satisfy QoS guarantee that is required for real time application services for emergency room, operating room etc. Accordingly, world-wide research is being made for a variety of services to provide QoS. he goal of DiffServ is to offer scalable differentiated service in Internet which are made possible by traffic classification and conditioning only performed at an edge(or a boundary) node. In case DiffServ was deployed in the Medical multimedia network, it is difficult to estimate how the QoS mechanism would affect totally the network performance. Therefore, we need to verify by simulation the design of algorithm which provide a variety of differentiated services. In QoS for Medical multimedia network, a simulator is designed and implemented using OPNET to investigate the performance of DiffServ QoS support mechanism. The developed DiffServ simulator may generate packets according to random, and bursty traffic models in order to incorporate diverse traffic conditions in the Medical multimedia network environment. Based on our simulation results, we confirmed that service differentiation is possible by using the EF(Expedited Forwarding) class in DiffServ networks.

• Journal of Korea Multimedia Society
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• v.17 no.12
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• pp.1453-1460
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• 2014

WFQ (Weighted Fair Queuing) provides not only fairness among traffic flows in using bandwidth but also guarantees the Quality of Service (QoS) that individual flow requires, which is why it has been applied to the resource reservation protocol (RSVP)-capable router. The RSVP allocates an enough resource to satisfy both the rate and end-to-end delay requirements of the flow in the condition of no packet loss, and the WFQ scheduler guarantees those QoS requirements with the allocated resource. In practice, however, most QoS-guaranteed services allow a degree of packet loss, especially from 0.1% to 3% for Voice over IP. This paper discovers that the packet loss rate of each traffic flow is determined by only its time-stamp adjustment value, and then enhances the WFQ to provide a differentiated packet loss guarantee under general traffic conditions in terms of both traffic characteristics and QoS requirements. The performance evaluation showed that the proposed WFQ could increase the utilization of bandwidth by 8~11%.

• The Transactions of the Korea Information Processing Society
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• v.6 no.8
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• pp.2042-2049
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• 1999

In contrast to traditional data communication, the multimedia communication must support variable requirements to multimedia application service. Specially, it is a critical issue that the synchronization supports a continuous and temporal relationship media playout in a distributed environment. But the continuously generated media in source can't guarantee the constant interval on playout for the destination due to the inconsistent network transmission delay and transmission error. In this paper, we introduce a intramedia synchronization mechanism for the continuous and synchronous playout of multimedia stream such as audio and video across a communication network. The proposed mechanism is based on the user defined QoS(Quality of Service) and the playout correction algorithm to guarantee the continuous media playout at the receiver.

• Proceedings of the Korea Society for Simulation Conference
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• 2003.06a
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• pp.61-66
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• 2003

Mobile IP has been designed only to maintain communication as they move form place to place, so it doesn't guarantee Quality of Service(QoS). QoS in mobile IP is important to provide multimedia and real-time applications services in mobile, and it is closely related to handoff delay. Therefore, handoff delay problem is actively studied to guarantee QoS as a main issue in mobile IP research area Next generation Mobile IPv6 resolve this problem somewhat, triangle problem for first packet and handoff delay still remain. In this paper, we suggest SNMP Information-based routing that adds keyword management method to Information-based routing in active network in order to resolve such a problem, and then suggest QoS controlled handoff based on SNMP Information-Based routing. After modeling of suggested method and existing handoff method simulations we carried out with NS-2 for performance evaluation. The results of simulations show the some improvement on handoff delay, and therefore on QoS improvement.

• Journal of the Korea Society for Simulation
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• v.12 no.3
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• pp.55-68
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• 2003

As mobile IP has been suggested only to support mobility of mobile station(MS) by which it dose nothing but guarantee MS's new connection to the network, it is for nothing in Quality of Service(QoS) after handoff of MS. QoS is very important factor in mobile IP network to provide multimedia applications and real-time services in mobile environment, and it is closely related to handoff delay Therefore as a main issue in mobile IP research area, handoff delay problem is actively studied to guarantee and promote QoS. In this paper, in order to resolve such a problem, we suggest Simple Network Management Network(SNMP) information-based routing that adds keyword management method to information-based routing in active network, and then propose QoS controlled handoff by SNMP information-based routing. After setting up routing convergence time, modeling of suggested method and existing handoff method is followed in order to evaluate the simulations that are carried out with NS-2. The result of simulation show the improvement of handoff delay, and consequently it turns off the QoS has been improved considerably.