• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1037-1043
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• 2006

This work presents an effective overlay multicast tree construction algorithm for synchronized real-time media multicast service over the Internet. The proposed algorithm is designed to minimize delay variance among group members to provide the synchronized service as well as average delay of group members in order to support the service in real-time. Basically, of orthogonal genetic algorithm is employed to obtain the near optimal tree with a low computational complexity since the given problem is NP-complete. Finally, experimental results are provided to show the superior performance of the proposed algorithm.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.11
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• pp.503-510
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• 1986

A new algorithm based on the concept of prediction error minimization is suggested to estimate the time varying delay in discrete processes. In spite of the existence of the stochastic noise, this algorithm can estimate time varying delay accurately. Computation time of this algorithm is far less than that of the previous extended parameter methods. With the use of this algorithm, generalized minimum variance control shows good control behavior in simulations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.982-983
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• 2013

This paper introduce a dynamic polling method for XG-PON systems and describes the performance evaluation results. We show the mean delay and delay variance of the introduced method and the existing method.

• Proceedings of the Korea Society for Simulation Conference
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• 2004.05a
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• pp.109-117
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• 2004

In this paper, we consider the aortic sinus baroreceptor, which is the most representative baroreceptor sensing the variance of pressure in the cardiovascular system, and propose heart activity control model to observe the effect of delay time in heart period and stroke volume under the regulation of baroreflex in the aortic sinus. The proposed heart activity baroreflex regulation model contains electric circuit sub-model. We constituted the time delay sub-model to observe sensitivity of heart activity baroreflex regulation model by using the variable value to represent the control signal transmission time from the output of baroreflex regulation model to efferent nerve through central nervous system. The simulation object of this model is to observe variability of the cardiovascular system by variable value in time delay sub-model. As simulation results, we observe three patterns of the cardiovascular system variability by the time delay, First, if the time delay over 2.5 second, aortic pressure and stroke volume and heart rate is observed nonperiodically and observed. Finally, if time delay under 0.1 second, then heart rate and aortic pressure-heart rate trajectory is maintained in stable state.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.8
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• pp.557-562
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• 1988

This paper presents a class of discrete adaptive controller that can be applied to a plant without sufficient a priori information. It is well known that the GMV(Generalized Minmum Variance) contrlller performs satisfactorily if the plant time delay is known. By introducing the long-range prediction into the GMV controller, robustness to the time delay can be improved, although optimality is lost. Such an idea motivates a predictive control system to be proposed here, where the system minimizes multi-stage cost via the GMV approach. Moreover, the detuning control weight is determined by an on-line tuning method. It is shown that robustness, computational efficiency, and performance of the resulting control system are improved as compared with those of the GPC(Generalized Predictive Control)system.

• The Transactions of the Korea Information Processing Society
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• v.2 no.5
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• pp.667-676
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• 1995

In ATM traffic multiplexing, the cell clumping and the cell dispersion are occured due to the cell delay variance(CDV) which changes the traffic characteristics. These cell variances increase the burstiness of t.he cell streams and make the network congested. The function of the traffic shaping is necessary to transmit the input streams into the networks or into the traffic policing schemes with some intevals. Most of the existing studies regard the input traffics as the traffic with the identical characteristics. In this study, the traffic shaping is processed by considering the traffic characteristICS with t.he loss-sensitive traffic and the delay-sensitive traffic. The traffic shaping model and the traffic shaping algorithm which considers the" characteristics of input streams have been presented. The traffic effect On t.he CDV size is also studied. The proposed scheme is compared to Virtual Scheduling Algorithm(VSA) and the efficiency of the proposed scheme is evaluated. According to the simulation results, t.he mean delay is decreased about 12% in delay-sensitive traffic and the traffic burstiness is decreased about 11 % in loss-sensitive traffic.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.215-218
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• 1998

This paper proposes a blind multi-user detector using Code-Constrained Minimum Variance (CCMV) method which directly detects the DS-CDMA signals in a multipath fading channel without estimating the channels. This algorithm reduces the complexity of computation by making a small size data matrix with the order of the channel length. Advantageously it requires to know the spreading code and the time delay of only the desired user.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.980-981
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• 2013

This paper introduces a new allocation method of unused bandwidth for TWDM PON and explains the performance evaluation results. Using computer simulations, we compare the mean delay and the frame delay variance of the proposed method with those of the existing method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10B
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• pp.916-926
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• 2003

The encryption of packets increases delay and delay jitter that may degrade the quality of service (QoS) in real-time communications. So, we analyzed the delay jitter, delay, and interval delay between consecutive packets which were encrypted by the DES, 3DES, SEED and AES algorithms in this study. The interval delay and jitter of three algorithms such as the DES, SEED, AES were similar to the results of no encryption. But in the case of 3DES, the encryption of packets increases the variance of interval delay and jitter in comparison with other algorithms. we also analyzed properties of security and an efficiency of RTP security between SRTP and H.235.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.2
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• pp.231-245
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• 1996

Semiconductor manufacturing line includes several batch processes which are to be controlled effectively to enhance the productivity of the line. The key problem in batch processes is a dynamic batch sizing problem which determines number of lots processed simultaneously in a single botch. The batch sizing problem in semiconductor manufacturing has to consider delay of lots, setup cost of the process, machine utilization and so on. However, an optimal solution cannot be attainable due to dynamic arrival pattern of lots, and difficulties in forecasting future arrival times of lots of the process. This paper proposes an efficient batch sizing heuristic, which considers delay cost, setup cost, and effect of the forecast errors in determining the botch size dynamically. Extensive numerical experiments through simulation are carried out to investigate the effectiveness of the proposed heuristic in four key performance criteria: average delay, variance of delay, overage lot size and total cost. The results show that the proposed heuristic works effectively and efficiently.