• The Journal of Natural Sciences
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• v.8 no.2
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• pp.93-99
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• 1996

In this study, we compare performance of priority schemes of FDDI and Expressnet for integrated voice and data traffic through simulation. The voice capacity of FDDI is higher than that of Expressnet for all cases considered. When compared to Expressnet, FDDI achieves a higher data throughput for file transfer traffic but it incurs a longer delay for interactive traffic.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.11 no.1
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• pp.16-24
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• 1986

The queueing delay and the response time of model of the buffer insertion LAN have been derived and its performance has been analyzed in terms of the throughput rate-response time characteristic. The results show that the response time can be improved by increasing the medium data rate, and that it can be reduced by 0.7 msec by transmitting the acknowledgement signal at the network interface unit(NIU) rather than at the hose, when the channel utilization is approximately 0.8. Also, implementation of the buffer insertion protocol has been studied.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.676-679
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• 1997

Networking for manufacturing is gaining importance as a nerve system of computer-integrated manufacturing(CIM). Among the various network types, the most inexpensive type called fieldbus is specifically aimed to interconnect simple devices such as sensors and actuators. For this purpose, there are several choices of the protocol such as Profibus, FIP, Foundation Fieldbus, and IEC/ISA fieldbus. This paper presents the simulation results of Profibus and FIP. Both protocols has been simulated in order to evaluate the performance such as transmission delay and throughput under different protocol parameter setting and traffic conditions.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.59-68
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• 1996

In this paper, we propose two types of WDMA protocol for multi-wavelength optical networks that have a dedicated control channel. Protocol type I is designed for the case that the number of nimislots is less than the number of nodes (La${\ge}$M). Proposed protocols employ the aging scheme to guarantee a fairness in the process of channel allocation. The perfomrance of proposed protocols are evaluated in terms of throughput and delay with variations in offered load. Simulation results show that the proposed protocols have superior performance to conventional protocols.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.6
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• pp.225-236
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• 2003

In this paper, we propose a wireless scheduling algorithm to provide the Internet delay proportional differentiated services in wireless networks. For considering network environments that have burst and location-dependent channel errors, our proposed WDPS(Wireless Delay Proportional Service) scheduling algorithm adaptively serves packets in class queues based on the delivered delay performance for each class. The remarkable characteristics of WDPS scheduler are supporting a fair relative delay service, providing graceful throughput and delay compensation, and avoiding class queue blocking problem. Through simulations, we show that the algorithm achieves the desirable properties to provide delay proportional services in wireless networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.45-57
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• 2005

In this paper, we extend the performance of bidirectional TCP connection over end-to-end network that uses transfer rate-based flow and congestion control. The sharing of a common buffer by TCP packets and acknowledgement has been known to result in an effect called ack compression, where acks of a connection arrive at the source bunched together, resulting in unfairness and degraded throughput. The degradation in throughput due to bidirectional traffic can be significant. Even in the simple case of symmetrical connections with adequate window size, the connection efficiency is improved about 20% for three levels of background traffic 2.5Mbps, 5.0Mbps and 7.5Mbps. Otherwise, the throughput of jitter is reduced about 50% because round trip delay time is smaller between source node and destination node. Also, we show that throughput curve is improved with connection rate algorithm which is proposed for TCP congetion avoidance as a function of aggressiveness threshold for three levels of background traffic 2.5Mbps, 5Mbps and 7.5Mbps. By analyzing the periodic bursty behavior of the source IP queue, we derive estimated for the maximum queue size and arrive at a simple predictor for the degraded throughput, applicable for relatively general situations.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1000-1005
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• 1993

In this paper asymptotic formulate for performance characteristics throughput, delay) of large scale token-passing networks with priorities and limited service are given. In particular, adaptive control procedures for obtaining optimal buffer capacity with respect to each priority and optimal limited service are shown. All results obtained are supported by simulations.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.37-42
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• 1992

The main purpose of the paper is to derive asymptotic formulae for performance characteristics(throughput, delay) of large-scale token-passing network with buffered stations and to optimize the buffer capacity with respect to the probability of data generation. We consider two versions of token-passing network: uniform and nonuniform token-passing time interval. All results obtained are supported by simulations.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.5
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• pp.810-816
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• 2001

This paper proposes a Truncated Type-II Hybrid ARQ scheme using an adaptive modulation system to achieve high throughput data transmission systems for mobile communication systems. In this paper, the adaptive modulation system analyzed in Nakagami (m-distribution) fading channel environment. The adaptive modulation system controls the modulation level and symbol rate according to the Nakagami fading parameter(m). When the received $E_bN_0$ is high or the Nakagami fading parameter m is high, the propose system selects higher modulation level and higher symbol rate to increase throughput. On the other hand, this system selects lower modulation level and lower symbol rate to prevent throughput performance degradation when the received $E_bN_0$ is low. The modulation method have been adopted QPSK(Quadrature Phase Shift Keying), 16 QAM(Quadrature Amplitude Modulation), 64 QAM, 256 QAM. Therefore, Adaptive Modulation Systems with Truncated Type-II Hybrid ARQ Scheme is proper for mobile and radio for mobile and radio data communication system that require high reliability and delay-limited applications.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.221-224
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• 2000

The issue of supporting TCP traffic over ATM networks is currently one of the most important issues in the field of data networks. One important part of this issue is congestion control. In general, congestion control uses method such as packet drop to relieve network resource when the network is congested so as to maintain high throughput and low delay. In addition, congestion control is required to ensure fair sharing of resources among all users during congestion. In this paper we propose a new congestion control method using WRED & per-VC accounting mechanism. This packet discard scheme is proposed with the goal to provide both good performance in terms of throughput and fairness in terms of bandwidth exploitation of the output link among all virtual circuits.