• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.85-90
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• 2002

Traffic specification plays a crucial role in the resource reservation for video services over the packet-switching networks. The current development of QoS-guaranteed service still leaves a wide space for the selection of traffic specification. We propose a new method to estimate the traffic specification of variable-bit-rate (VBR) video for deterministic service. The method is based on the concept of empirical envelope and the delay bound. The solution shows to be simple yet it provides excellent network utilization.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.641-644
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• 2017

Usage of LTE(Long Term Evolution) technology is expanded to industrial an emergency service field beyond commercial communications of mobile internet focused on smartphone. In this paper, transmission performance of LTE technology be supplied to various service area is analyzed on the level of application traffics. Performance is evaluated with compter simulation based NS(Network Simulator)-2, CBR(Constant Bit Rate), VBR(Variable Bit Rate File) traffic is used as simulation target. Results and methods of this paper can be used for research and developmemt of LTE based networks.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.131-134
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• 2000

Only MAC protocol can satisfy the service quality of the request of bandwidth, delay time, and cell loss at the same time and it is because MAC protocol provides mobile terminal an environment to use channel evenly and effectively This Paper has been adapted Mobile ATM Standardization of ETSI in maximum and used not only for practicing in-band signal to a priority order but also to the next reserved slot assignment of the dynamic frame. Also, by accepting VBR traffic more adaptively, the effectiveness of transmission channel has been maximized as well, and these are compared with the old way of it and analyzed to confirm the effectiveness.

• The KIPS Transactions:PartC
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• v.8C no.4
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• pp.443-450
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• 2001

본 논문에서는 무선 ATM 망에서 VBR(Variable Bit Rate) 트래픽의 QoS(Quality of Service)를 보장하고 무선 채널의 효율성을 극대화 할 수 있는 새로운 동적 슬롯 할당 알고리즘인 NDSA(Neural Dynamic Slot Assignment)를 제안한다. 제안된 알고리즘에서는 ATM 셀 헤더 부분의 GFC(Generic Flow Control) 필드 상에 단말기의 버퍼 상태와 셀 발생률 변화를 부호화 하여 piggybacking 하는 in-band 방식을 채택하였으며 다음 프레임에 할당할 슬롯의 갯수를 기존 방식과는 달리 신경회로망을 이용하여 유동적으로 조절하여 할당함으로써 단말기의 셀 손실이나 지연에 대한 QoS를 보장하고 채널 이용 효율을 높일 수 있었다. 제안된 알고리즘은 BONeS tool을 이용한 시뮬레이션을 통하여 기존의 방식과 비교 분석한 결과 그 정당성을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.1161-1164
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• 2001

본 논문에서는 무선 ATM 망에서 VBR(Variable Bit Rate) 트래픽의 QoS(quality of Service)를 보장하고 무선 채널의 효율성을 극대화 할 수 있는 새로운 적응적 슬롯 할당 알고리즘인 In-VDSA를 제안한다. 제안된 알고리즘에서는 ATM 셀 헤더 부분의 GFC(Generic Flow Field) 필드 상에 단말기의 버퍼 상태를 부호화하여 piggybacking하는 방식을 채택하였으며 다음 프레임에 할당할 슬롯의 개수를 기존의 다른 방식과는 달리 유동적으로 조절하여 할당함으로써 단말기의 셀 손실이나 지연에 대한 QoS를 보장하고 채널 이용 효율을 높일 수 있었다. 제안된 알고리즘은 BONeS tool을 이용한 시뮬레이션을 통하여 기존의 방식과 비교 분석한 결과 그 정당성을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2000.04a
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• pp.440-446
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• 2000

초고속통신의 실현과 다양한 멀티미디어 서비스를 위한 해결책으로서 ATM이 널리 사용되고 있다. TCP가 ATM망의 ABR/UBR 서비스를 사용할 때, ABR/UBR 제어방식과 TCP 흐름제어 사이의 서로 다른 동작 때문에 TCP 파라미터 값이 TCP층의 성능뿐만 아니라 ATM 층에도 영향을 미쳐 처리율과 공정성의 성능저하를 가져온다. 본 논문에서는 효과적인 처리율과 공정성의 관점에서 실제 통신망을 고려하여 VBR서비스 상에서의 TCP 트래픽의 성능향상을 위해 효과적인 파라미터 제어운용 방안을 제시하고, 시뮬레이션 결과를 통해 개선된 높은 처리율과 공정성을 나타내었다.

• 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.

• Journal of the Korea Computer Industry Society
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• v.2 no.11
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• pp.1395-1406
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• 2001

In order to cover a widespread service range, terrestrial/satellite-mixed network is being combined with terrestrial ATM network. This dissertation analyzes and investigates several previously existent CDV compensation methods in order to compensate CDV arising from interfacing satellite TDMA and ATM. Specifically to supplement the problems of timestamp and cell number counting methods, new Variable Timestamp method for CDV compensation is proposed. To evaluate the proposed method, MMPP(Markov Modulated Poisson Process), which can express VBR service very well, is selected as a cell input traffic model of terrestrial transmitting earth station. After several simulation, it is also confirmed that CDV compensation capability for VBR services is very superior to the cell number counting method. In this case, as the timestamp number Nts increases, CDV compensation capability increases, and the CDV distribution length is reduced.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.37 no.1
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• pp.12-22
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• 2000

This paper presents the window-based permit distribution scheme for efficient medium access control to support multiclass traffic in APON(ATM over passive optical network). The proposed MAC protocol considers the characteristics of QoS(Quality of Service) for various traffic classes. A periodic RAU(request access unit) in upstream direction, includes dedicative request fields for each traffic category within the request slot. The transmission of upstream cell is permitted by the proposed window-based spacing scheme which distributes the requested traffic into several segments in the unit of one spacing window. The delay sensitive traffic source such as CBR or VBR with the stringent requirements on CDV and delay, is allocated prior to any other class. In order to reduce the CDV, so that the permit arrival rate close to the cell arrival rate, Running-Window algorithm is applied to permit distribution processing for these classes. The ABR traffic, which has not-strict CDV or delay criteria, is allocated flexibly to the residual bandwidth in FIFO manner. UBR traffic is allocated with the lowest priority for the remaining capacity. The performance of proposed protocol is evaluated in terms of transfer delay and 1-point CDV according to various offered load. The simulation results show that our protocol has the prominent improvement on CDV and delay performance with compared to the previous protocol.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.95-98
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• 1998

In this paper, we propose a cell scheduling algorithm for ABR traffic in ATM multiplexer. Proposed Algorithm can support ABR service more efficiently than existing WRR and DWRR algorithm. We evaluate the performances of proposed algorithm through computer simulation. Also, we model the VBR and the ABR traffics as ON/OFF source, and the CBR traffic as a Poisson source. And the simulation shows that proposed algorithm better performance over other cell scheduling algorithm in tem of mean cell delay time.