• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.1
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• pp.87-99
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• 1998

In the multicasting communications, the quality of service is not guaranteed occasionally, according to the shortage of resources, because all resources such as communication buffer, processing power for the packet multiplication, and bandwidth, should be shared among each members. This problem can be solved through the hierarchical multicaster construction mechanism which guarantees that all multicaster can be operated within the required performance. This paper proposes the architecture of multipoint communication server based on hypercube type massively parallel computer. Through the simulation, it is verified that the traffic of links between each node of hypercube computer is under the some bandwidth. So, it is certified that the hypercube computer is suitable for the multicast communication servers supporting the various groups.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.1
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• pp.94-101
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• 2007

Streaming video is expected to become a key service in the developing heterogeneous wireless network. However, sufficient quality of service is not offered to video applications because of bursty packet losses. An effective solution for packet loss in wireless network is to perform a proper concealment at the receiver. However, most concealment methods can not conceal effectively the consecutively damaged macro blocks, since the neighboring blocks are lost. In the previous work, bidirectional motion vector tracking (BMVT) method has been proposed which uses the moving trajectory feature of the damaged macro blocks. In this paper, a channel-adaptive redundancy coding method for the better BMVT error concealment is presented. The proposed method provides enhanced video quality at the cost of a little bit overhead in the wireless error-prone network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11B
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• pp.969-978
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• 2006

Recently, there has been explosive growth in Internet service contents, and we have witnessed the emergence of many real-time applications on the Internet. These types of applications require special support from the underlying network such as reliability, timeless, and guaranteed delivery, as well as different levels of service quality. Estimation network status and transcoding data rate are researching for QoS of multimedia service by using the RTP/RTCP. We propose two schemes that the way to calculate the one-way delay by expanding the structure of RTP/RTCP in Internet that provides us 'best effort' service and to estimate the network condition by using this in this paper. And we propose the dynamic RTCP mechanism based on one-way delay to deal with rapidly changed network situation immediately. In simulation, proposed monitoring schemes using the one-way delay has similar in performance to monitoring schemes using the GPS, proposed dynamic RTCP scheme obtain the desired result of decreased packet loss rate by sending RTCP RR packet lower than other schemes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12B
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• pp.1100-1105
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• 2003

In this paper, we propose a solution, called DQDMR, for generating delay-constrained bandwidth- appropriated multicast routing trees to reduce end-to-end delay and conserved bandwidth resources. At the current router system the router keep the information of link which neighboring node in the routing table to guarantee QoS(Quality of Service). When we construct multicast tree, DQDMR algorithm dynamically adjusts the path in the least delay and appropriate bandwidth. Through simulations comparing to another multicast algorithms, we reach a conclusion that DQDMR algorithm can simply and dynamically adjusts the construction of multicast tree in hight-speed and conserve bandwidth resources.

• Journal of Broadcast Engineering
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• v.20 no.1
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• pp.40-47
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• 2015

This paper discusses QoS enhancement in the Best-effort services of the service plan provided by MPEG Media Transport (MMT) systems for video streaming applications. Among MMT services, i.e. per-flow, per-class, and best-effort services, the server does not provide guaranteed bandwidth for the best-effort service only. Therefore, in the best-effort services, a bandwidth access priority is defined for various services, where the lowest priority is assigned to the low-level video services. To alleviate the issue of bandwidth limitation in the best-effort services, this paper investigates transmission of low-resolution video with low bitrate and up-sampling. Our experimental results prove the superiority of the proposed method in terms of delivered video quality.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6A
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• pp.371-378
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• 2003

In Code Division Multiple Access (CDMA) system, the cell capacity is defined as the number of available channels in a cell, which is limited by the interferences. When a new call is accepted at its home cell, this adds the interference to the home and its neighboring cells. This paper proposes a call admission control based on mobile transmission power prediction. The home cell has enough capacity to admit new call and if home cell would have admitted a new call, it calculates the mobile transmission power. Also, its neighboring cell can predict the amount of interference using the predicted mobile transmission power. Thus, the new mobile is accepted by its home cell if QoS(Quality Of Service) is guaranteed in its neighboring cells. The simulation result shows that the proposed scheme largely reduces the outage probability in the neighboring cells.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.837-844
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• 2019

In this paper, we propose the AMBM(: Adaptive Multi-channel Backoff Machisum) -Mac protocol to provide high throughput for non-safety applications in VANET(: Vehicular Ad Hoc Networks) environment. The proposed protocol guarantees the quality of service of non-safety packets by dynamically adjusting CW(: Channel Window) of WSA(: WAVE Service Advertisement) to maximize throughput between non-safety packets of different priority. It also shows that allocating a large amount of time for channel coordination and time slot reservation for SC and dynamically adjusting CW and CCI as nodes increase to reduces transmission delay than IEEE 1609.9, C-MAC(: Coordinated multi-channel MAC, and Q-VCI(: QoS Variable CCH Interval) protocols.

• Journal of KIISE:Information Networking
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• v.34 no.4
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• pp.239-245
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• 2007

New multimedia services over the cellular/WLAN overlay networks require different Quality of Service (QoS). In the cellular/WLAN overlay structure, the main issue of load balancing is to balance the available bandwidth among different networks. In this paper, we propose a new online network management scheme. Our proposed scheme is designed to improve bandwidth utilization by balancing the traffic load between the cellular network and WLANs. Simulation results indicate the superior performance of our proposed framework to strike the appropriate performance balance between contradictory QoS requirements under widely varying diverse traffic loads.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.10
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• pp.75-80
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• 1999

Multimedia synchronization model for distributed, continuous or discrete media that was guaranteed high quality of service is requited in developing multimedia application software. In this paper we have specific object controller which is called dynamic key media that is changed by user event generation. This becomes media whose event occurrence and periods can't be predicted. For event occurrence not only audio but also text and image can be chosen for key media and performs its role. Object controller transfers information for next transition. The proposed model offers high qualify of services by permitting maximum allowed jitter and skew in playout time and verified its effectiveness by simulation.

• The Journal of the Korea institute of electronic communication sciences
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• v.5 no.2
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• pp.193-204
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• 2010

Since Wireless Multimedia Sensor Network(WMSN) needs to process various multimedia data such as audio, image and video data as well as scalar data, it requires a mechanism that can support Quality of Service(QoS) to handle efficiently. This paper classifies traffic in WMSN as periodic monitoring traffic, event traffic, multimedia traffic and query-based traffic, proposes marking algorithm and queue management mechanism that guarantee differentiated QoS in terms of delay, energy efficiency and credibility on each traffic and conduct performance analysis with simulation.