• The KIPS Transactions:PartC
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• v.10C no.7
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• pp.899-914
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• 2003

It is generally accepted that self-similar (or fractal) processes may provide better models for teletraffic in modern telecommunication networks than Poisson Processes. If this is not taken into account, it can lead to inaccurate conclusions about performance of telecommunication networks. Thus, an important requirement for conducting simulation studies of telecommunication networks is the ability to generate long synthetic stochastic self-similar sequences. Three generators of pseudo-random self-similar sequences, based on the FFT〔20〕, RMD〔12〕 and SRA methods〔5, 10〕, are compared and analysed in this paper. Properties of these generators were experimentally studied in the sense of their statistical accuracy and times required to produce sequences of a given (long) length. While all three generators show similar levels of accuracy of the output data (in the sense of relative accuracy of the Horst parameter), the RMD- and SRA-based generators appear to be much faster than the generator based on FFT. Our results also show that a robust method for comparative studies of self-similarity in pseudo-random sequences is needed.

• Journal of Digital Contents Society
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• v.5 no.1
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• pp.7-11
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• 2004

There are many problems that must solve to construct next generation high-speed communication network. Among these, item that must consider basically is characteristics analysis of traffic that nows to network Traffic characteristics of many Internet services that is offered present have shown that network traffic exhibits at a wide range of scals-self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all, for design and dimensioning of next generation communication network, traffic model that are reflected burstiness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, the calculation equation is derived considering queueing delay and self-similarity of data traffic art compared with simulation results.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.175-181
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• 2005

Recent measurements of local-area and wide-area traffic have shown that network traffic exhibits at a wide range of scales-Self-similarity. Self-similarity is expressed by long term dependency, this is contradictory concept with Poisson model that have relativity short term dependency. Therefore, first of all for design and dimensioning of next generation communication network, traffic model that are reflected burstness and self-similarity is required. Here self-similarity can be characterized by Hurst parameter. In this paper, when different many data traffic being integrated under various environments is arrived to communication network, Hurst Parameter's change is analyzed and compared with simulation results.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.281-288
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• 2005

It is generally accepted that self-similar (or fractal) Processes may provide better models for teletraffic in modem computer networks than Poisson processes. f this is not taken into account, it can lead to inaccurate conclusions about performance of computer networks. Thus, an important requirement for conducting simulation studies of telecommunication networks is the ability to generate long synthetic stochastic self-similar sequences. A generator of pseudo-random self similar sequences, based on the SRA (successive random addition) method, is implemented and analysed in this paper. Properties of this generator were experimentally studied in the sense of its statistical accuracy and the time required to produce sequences of a given (long) length. This generator shows acceptable level of accuracy of the output data (in the sense of relative accuracy of the Hurst parameter) and is fast. The theoretical algorithmic complexity is O(n).

• The KIPS Transactions:PartC
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• v.11C no.5
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• pp.621-632
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• 2004

Recent measurement studies of real teletraffic data in modern telecommunication networks have shown that self-similar (or fractal) processes may provide better models of teletraffic in modern telecommunication networks than Poisson processes. If this is not taken into account, it can lead to inaccurate conclusions about performance of telecommunication networks. Thus, an important requirement for conducting simulation studies of telecommunication networks is the ability to generate long synthetic stochastic self-similar sequences. A new generator of pseu-do-random self-similar sequences, based on the fractional Gaussian nois and a wavelet transform, is proposed and analysed in this paper. Specifically, this generator uses Daubechies wavelets. The motivation behind this selection of wavelets is that Daubechies wavelets lead to more accurate results by better matching the self-similar structure of long range dependent processes, than other types of wavelets. The statistical accuracy and time required to produce sequences of a given (long) length are experimentally studied. This generator shows a high level of accuracy of the output data (in the sense of the Hurst parameter) and is fast. Its theoretical algorithmic complexity is 0(n).

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.640-642
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• 2002

본 논문에서는 실제 네트워크에서 측정되고 있는 시간축상으로 매우 불안정한 상태의 트래픽 즉, ON／OFF 소스 모델로 가정하여 발생시킨 self-similar 트래픽을 이용하여 다단으로 이루어진 스위치 모델의 처리시간(processing time)에 따른 출력단에서self-similarity의 변화와 이용도(utilization) 등을 사용하여 네트워크의 성능을 분석한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.235-237
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• 2003

멀티미디어 데이터 전송이 가능한 초고속 통신망의 발달로 음성을 위주로 서비스하던 과거와는 다른 self-similar 특성을 갖는 데이터 트래픽이 발생된다는 것이 알려지고 있다. 이러한 트래픽은 전통적인 네트워크 해석 방법인 포와송 트래픽 모델과는 상당히 차이가 난다는 것이 여러 트래픽의 측정 결과 나타나고 있다. 본 논문에서는 공유 메모리를 갖는 CS(Complete Sharing), DT(Dynamic Threshold), PO(Push-Out) 그리고, SMXQ(Sharing with Maximum Queue)와 같은 다양한 ATM(Asynchronous Transfer Mode) 스위치의 버퍼 관리 기법을 이용하여 입력포트에 self-similar 성질을 갖는 트래픽이 들어올 때 출력포트에서의 self-similarity와 셀 손실률 그리고, 이용률 등을 분석한다.

• Proceedings of the Korea Society for Simulation Conference
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• 2001.05a
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• pp.127-131
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• 2001

휴대용 단말기와 이동통신 기술의 발달로 무선 네트워크의 사용이 급증하면서 호스트가 이동중에도 지속적인 네트워킹이 가능한 프로토콜들이 개발되고 있다. Mobile IP는 이동 노드(mobile node)가 인터넷상의 임의의 다른 위치에 접속하여 IP 주소를 변경하지 않고, 홈 주소를 이용하여 통신하며 위치에 따른 care-of address에 의해 데이타를 터널링하여 전달받는다. 본 논문에서는 컴퓨터 시뮬레이션을 통해 self-similar 트래픽을 갖는 mobile IP의 성능을 분석한다. 일반적으로 데이타 트래픽, 바인딩 갱신시간, 버퍼관리 방법 등은 핸드오프 동안 mobile LP의 성능에 많은 영향을 비친다. 따라서 시뮬레이션 모델을 이용하여 self-similar 트래픽 환경에서 위에 언급된 성능 파라미터들의 영향을 분석한다.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.294-297
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• 2006

Measurement of network traffic have shown that the self-similarity is a ubiquitous phenomenon spanning across diverse network environments. In previous work, we have explored the feasibility of exploiting the long-range correlation structure in a self-similar traffic for the congestion control. we show that a multiple time scale TCP endows the underlying feedback control with proactivity by bridging the uncertainty gap associated with reactive controls which is exacerbated by the high delay-bandwidth product in broadband wide area networks. Third, we investigate the influence of the three traffic control dimensions-tracking ability, connection duration, and fairness-on performance.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.136-138
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• 2003

빠른 속도와 넓은 대역폭을 이용한 멀티미디어 데이터 전송이 가능하게 됨으로써 패킷 스위칭 네트워크로부터 발생되는 트래픽은 burstiness 성질을 보여준다. 이러한 트래픽은 전통적인 해석적 방법에서 네트워크의 성능평가를 위해 사용되고 있는 트래픽 모델과는 상당히 다른 self­similar 트래픽 성질을 갖고 있다는 것이 실제 트래픽을 측정한 결과 나타나고 있다. 일반적으로 ATM 스위치는 패킷을 효율적으로 전송하기 위해 다양한 공유 버퍼관리 방법을 적용한다. 따라서 본 논문에서는 공유 버퍼를 사용하여 다중 스위치로 상호 연결된 ATM 스위치에서 self­similar 트래픽이 이웃 스위치들 간에 미치는 영향을 통하여 초고속 네트워크의 성능을 분석한다.