• Title/Summary/Keyword: 손실확률

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Heterogeneous 입력원을 갖는 ATM 스위치의 셀 손실확률 추정을 위한 Hybrid 시뮬레이션 기법

  • 김지수;전치혁
    • Proceedings of the Korea Society for Simulation Conference
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    • 1996.05a
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    • pp.9-9
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    • 1996
  • 광대역 종합정보 통신망의 핵심요소라 할 수 있는 ATM 스위치의 성능척도 중 가장 중요하게 다루어지고 있는 것은 셀 손실확률과 셀 전달지연시간이다. 이 중에서도 샐 손실확률기 추정에 대한 연구가 활발히 진행되고 있는데, ATM 스위치는 손실에 민감한 트래픽까지도 제대로 다루기 위하여 정도까지의 샐 손실확률을 보장할 수 있어야 한다. 이와같은 희소사건(rare event)의 확률 추정에 있어 원하는 정도의 precision을 가능한한 적은비용으로 얻어내기 위한 분산축소기법은 필수적이라 할 수 있다. Homogeneous 입력원을 갖는 ATM 스위치의 셀 손실확률 추정에 관련된 이전의 연구결과는 시뮬레이션과 분석적기법을 혼합시켜 얻어지는 새로운 개념의 추정치, 즉 hybrid 시뮬레이션 추정치의 도입을 통하여 상당한 정도의 분산축소 효과를 거둘 수 있음을 나타내주고 있다. 본 연구는 이에 대한 확장으로, 각각의 도착 프로세스가 서로 다른heterogeneous 입력원을 갖는 ATM 스위치의 셀 손실화률 추정에 적용될 수 있는 hybrid 시뮬레이션 기법을 개발하고자 한다. 사용된 모델은 이산시간대기모델()로 각입력원의 도착 프로세스는 Interrupted Bernoulli Process로 가정하였으며, 분석적 기법의 적용을 위한 입력원 통합(aggregation) 알고리듬과 실제 시뮬레이션 방법 등을 제시하였다. 또한 제시된 기법의 성능은 기존의 일반적인 시뮬레이션 추정치를 이용하여 얻어진 결과와의 비교를 통하여 분석되었다.

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Adaptive Call Admission Control Based on Resource Prediction by Neural Network in Mobile Wireless Environments (모바일 무선환경에서 신경망 자원예측에 의한 적응 호 수락제어)

  • Lee, Jin-Yi
    • Journal of Advanced Navigation Technology
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    • v.13 no.2
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    • pp.208-213
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    • 2009
  • This paper presents an adaptive call admission control(CAC) algorithm based on a target handoff call dropping probability in mobile wireless environments. This method uses a neural network for predicting and reserving the bandwidth demands for handoff calls and new calls. The amount of bandwidth to be reserved is adaptively adjusted by a target value of handoff call dropping probability(CDP). That is, if the handoff CDP exceeds the a target CDP value, the bandwidth to be reserved should be increased to reduce the handoff dropping probability below a target value. The proposed method is intended to prevent from increasing handoff call dropping probability when bandwidth to be reserved is not enough for handoff calls due to an uncertain prediction. Our simulations compare the handoff CDP in proposed CAC with that of an existing CAC. Results show that the proposed method sustains handoff call dropping probability below our target value.

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Markov Modeling of Multiclass Loss Systems (멀티클래스 손실시스템의 마코프 모델링)

  • Na, Seong-Ryong
    • The Korean Journal of Applied Statistics
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    • v.23 no.4
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    • pp.747-757
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    • 2010
  • This paper studies the Markov modeling of multiclass loss systems supporting several kinds of customers. The concept of unit for loss systems is introduced and the method of equal probability allocation among units is especially considered. Equilibrium equations and limiting distribution of the loss systems are studied and loss probabilities are computed. We analyze an example of a simple system to gain an insight about general systems.

Approximations to blocking probability in two-stage queueing model (이단계 대기모형에서 손실확률에 대한 근사)

  • 서정강;이계민
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.22 no.12
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    • pp.2644-2652
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    • 1997
  • We ivestigate a two-stage queueing system which frequently arises in the study of overflow problems. A primary service facility consists of multiple primary queues where blocked calls are overflowed to a secondary queue. By approximating the input to the secondary queue with a two-state Markov Modulated Poisson Process (MMPP), we derive the blocking probability of the secondary queue. For the approximation, we employ the well-known Heffes' method and the SAM procedure.

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Channel Allocation Using Mobile Mobility and Neural Net Spectrum Hole Prediction in Cellular-Based Wireless Cognitive Radio Networks (셀룰러 기반 무선 인지망에서 모바일 이동성과 신경망 스펙트럼 홀 예측에 의한 채널할당)

  • Lee, Jin-yi
    • Journal of Advanced Navigation Technology
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    • v.21 no.4
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    • pp.347-352
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    • 2017
  • In this paper, we propose a method that reduces mobile user's handover call dropping probability by using cognitive radio technology(CR) in cellular - based wireless cognitive radio networks. The proposed method predicts a cell to visit by Ziv-Lempel algorithm, and then supports mobile user with prediction of spectrum holes based on CR technology when allocated channels are short in the cell. We make neural network predict spectrum hole resources, and make handover calls use the resources before initial calls. Simulation results show CR technology has the capability to reduce mobile user handover call dropping probability in cellular mobile communication networks.

A Study on the Performance of Priority Mechanisms in ATM Multiplexer (ATM 멀티플렉서에서의 우선순위 메카니즘에 관한 연구)

  • 윤성호;박광채;이재호
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.6
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    • pp.779-792
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    • 1993
  • In a switching node or an ATM multiplexer of the ATM network, a good bandwidth utilization can be achieved by the priority control using the 1-bit(Cell Loss priority) in ATM cell header. In this paper, the mixed mechanism is proposed to make up for shortcomings of existing space priority control mechanisms and to decrease the loss probability of high priority cell and its performance is analyzed about the cell loss probability. To estimate the performance of proposed mixed mechanism, its cell loss probability is compared with those of non-priority mechanism, push-out mechanism and partial buffer sharing mechanism. The cell loss probability is analyzed using a M/D/1/N modeling and a 2-state MMPP/D/1/N modeling and also comparison between two modelings is made. To verify this result of numerical analysis, the computer simulation is performed for each mechanism using the simulation language, SIMSRIPT II.5.

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Adaptive Call Admission Control Based on Spectrum Holes Prediction in Cognitive Radio Networks (인지라디오망의 스펙트럼홀 예측기반 적응 호수락제어기법)

  • Lee, Jin-yi
    • Journal of Advanced Navigation Technology
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    • v.20 no.5
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    • pp.440-445
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    • 2016
  • There is a scheme where secondary users (SU) use predicted spectrum holes for primary users (PU) not to utilize for efficient utilization of the limited spectrum resources in cognitive radio networks. In this paper, we propose an adaptive call admission control framework that minimizes spectrum hopping call dropped probability (SHDP) for satisfying SU quality of service (QoS). The scheme is based on a call admission control (CAC), bandwidth prediction and adaptive bandwidth assignment. The prediction model predicts not only the number of spectrum holes, but requested bandwidth of SU spectrum hopping call, and then the CAC minimizes SHDP via an adaptive bandwidth assignment in resources not being enough for reservation. We bring Wiener prediction model to predict the resources. Simulations are conducted to compare the performance of proposed scheme with an existing, and show its ability of minimizing the SHDP.

Performance Comparison of Call Admission Control Based on Predictive Resource Reservations in Wireless Networks (무선망의 자원예측에 의한 호 수락제어방식의 성능비교)

  • Lee, Jin-Yi
    • Journal of Advanced Navigation Technology
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    • v.13 no.3
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    • pp.372-377
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    • 2009
  • This paper evaluates the performance of three methods for predicting resources requested by mobile's calls and a call admission algorithm based on these predicting methods respectively in wireless networks. The first method is based on Wiener prediction model and the second method is based on the MMOSPRED algorithm and the third method is based on the neural network. The proposed call admission algorithm is based on prioritized handoff call in resource allocation. The resources for future handoff calls are therefore predicted and reserved in advance, and then new calls are admitted as long as the remaining resources are sufficient. We compare their performances in terms of prediction error, new call blocking and handoff dropping probabilities by simulation. Results show that the CAC based on Wiener prediction model performs favorably due to exact resources prediction.

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Analysis of influential factors in whole life insurance model (종신보험에서의 영향 변수의 영향력 분석에 관한 연구)

  • Hyeon, Jeong-Min;Cha, Ji-Hwan
    • Journal of the Korean Data and Information Science Society
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    • v.21 no.1
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    • pp.71-86
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    • 2010
  • In life insurance, the net premium is derived based on the expected life time distribution and expected interest rate. The losses or risks of the insurer are significantly affected by the obtained net premium. Thus, in life insurance, these two factors, the life time distribution and expected interest rate, are considered as important influential factors. In this paper, we investigate the effect of these influential factors on the net premiums, management risks, and the probability of losses. Furthermore, relative influence of these factors is also studied.