• Title/Summary/Keyword: Overflow

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Approximate Cell Loss Performance in ATM Networks: In Comparison with Exact Results

  • Lee, Hoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.4A
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    • pp.489-495
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    • 2000
  • In this paper we propose an approximate method to estimate the cell loss probability(CLP) due to buffer overflow in ATM networks. The main idea is to relate the buffer capacity with the CLP target in explicit formula by using the approximate upper bound for the tail distribution of a queue. The significance of the proposition lies in the fact that we can obtain the expected CLP by using only the source traffic data represented by mean rate and its variance. To that purpose we consider the problem of estimating the cell loss measures form the statistical viewpoint such that the probability of cell loss due to buffer overflow does not exceed a target value. In obtaining the exact solution we use a typical matrix analytic method for GI/D/1B queue where B is the queue size. Finally, in order to investigate the accuracy of the result, we present both the approximate and exact results of the numerical computation and give some discussion.

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A Study on the Scaling in Wave Digital Filter (웨이브 디지털 필터의 스케일링에 관한 연구)

  • 권희훈;김명기
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.12 no.1
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    • pp.27-35
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    • 1987
  • Digital filter suffer from roundoff noise and adder overflows due to finite word length effects. Scaling is an attempt to internal signal levels such that all signals are as large as possible, yet without the occurrence of overflows. Scaling requirements are implemented by the use of transformer. This paper proposes a procedure for scaling wave digital filters to avoid overflow problems and at the same time maximizing the output signal-to-noise ratio. Results indicate that the scaled networks have an improved signal to noise ratio over th unscaled filters under the condition that there be no overflow occuring.

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A Study on Construction of Multiple-Valued Multiplier over GF($p^m$) using CCD (CCD에 의한 GF($p^m$)상의 다치 승산기 구성에 관한 연구)

  • 황종학;성현경;김흥수
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.31B no.3
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    • pp.60-68
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    • 1994
  • In this paper, the multiplicative algorithm of two polynomials over finite field GF(($p^{m}$) is presented. Using the presented algorithm, the multiple-valued multiplier of the serial input-output modular structure by CCD is constructed. This multiple-valued multiplier on CCD is consisted of three operation units: the multiplicative operation unit, the modular operation unit, and the primitive irreducible polynomial operation unit. The multiplicative operation unit and the primitive irreducible operation unit are composed of the overflow gate, the inhibit gate and mod(p) adder on CCD. The modular operation unit is constructed by two mod(p) adders which are composed of the addition gate, overflow gate and the inhibit gate on CCD. The multiple-valued multiplier on CCD presented here, is simple and regular for wire routing and possesses the property of modularity. Also. it is expansible for the multiplication of two elements on finite field increasing the degree mand suitable for VLSI implementation.

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Processing of Congestion Problem in the Interworking Node (연동 노드에서 집중 문제 처리)

  • 김평중
    • Journal of the Korean Professional Engineers Association
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    • v.29 no.3
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    • pp.94-104
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    • 1996
  • When Broadband Integrated Services Digital Network(BISDN) becomes commercially available In public network, conventional Local Area Network(LAN)s will still be in use. The first wide spread application for B-ISDN will be the interconnection of LANs. The equipment providing the connection between the LAN and the BISDN will be given the general name Inter Working Unit(IWU). We addresses the congestion problem of many interworking issues. In this paper, Our study is concentrated on applying connectionless network protocol for interworking. We suggest a rate control method in the network layer to prevent a buffer overflow in the IWU. Since this rate control method can be applied to prevent buffer overflow in a congested IWU, We investigate the use of rate control to solve congestion problems of IWU and parallize network layer with rate control to lessen the congestion problem in IWU.

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Implementation of the Multi-Channel Network Controller using Buffer Sharing Mechanism (버퍼공유기법을 사용한 멀티채널 네트워크 컨트롤러 구현)

  • Lee, Tae-Su;Park, Jae-Hyun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.4
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    • pp.784-789
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    • 2007
  • This paper presents an implementation of a new type of architecture to improve an overflow problem on the network buffer. Each receiver channel of network system stores the message in its own buffer. If some receiver channel receives many messages, buffer overflow problem may occur for the channel. This paper proposes a network controller that implements a receiver channel with shared-memory to save all of the received messages from the every incomming channels. The proposed architecture is applied to ARINC-429, a real-time control network for commercial avionics system. For verifying performance of the architecture, ARINC-429 controller is designed using a SOPC platform, designed by Verilog and targeted to Xilinx Virtex-4 with a built-in PPC405 core.

Analysis for Brazing Failure of Liquid Thruster (소형 액체 추력기 Brazing Failure 사례 분석)

  • Kim Jung-Hun;Jang Ki-Won;Lee Jae-Won;Lee Hae-Heon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.05a
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    • pp.23-27
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    • 2006
  • Brazing Failure has been occurred in the process of thrust chamber assembly. The possible factors have been analyzed by sample tests. The actual causes of 'Overflow' phenomenon have been investigated horn Brazing Material and fabrication of Piece Parts. The rejection rate of process has been improved by appling this results to a real brazing process.

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A comparative study on flood routing methods in irrigation reservoir (농업용 저수지 홍수추적방법의 비교)

  • Koo, Hee-Jin;Kim, Tai-Cheol;Kim, Dae-Sik
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2003.10a
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    • pp.299-302
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    • 2003
  • This study aims to apply and compare flood routing methods for irrigation reservoirs. In this research, three methods, which are the storage indication method(SIM), the mass curve method(MCM), the frog method(FM) were adopted and applied to two storm events of July $9{\sim}10\;and\;22{\sim}23$ of Donghwa-dam and its watershed located on Jangsoo-gun, Chunnam province. As the application results MCM showed the highest value at peak overflow and goodness-of-fit to the observed value, although the others also had similar value with the observed one. In analyzing lag time of peak between inflow and overflow MCM and SIM showed 7 hours, while FM showed 6 hours for the first storm event, and all three methods showed 3 hours for the second event.

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A study on the overload control of the ATM switching system (ATM 교환기 과부하제어 연구)

  • 기장근;최진규;김영선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.21 no.4
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    • pp.952-960
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    • 1996
  • In this paper, a new overload control scheme is proposed for a control system in ATM switching system. The proposed control scheme includes a counter that conunts the number of accepted calls and is decreased at cach D time interval. In overload condition of call processor, the control scheme detects over load condition when the counter value reaches a certain threshold value. Under overload condition, processor utilization is measured and the value of the D is updataed according to the difference between measured processor utilization and target utilization. A new call is accepted accepted only if the value of the counter is less than the threshold value. In overflow condition of cell traffic, accept probability of new call is reduced exponetially according to the elapsed time. The results of simulation show that the proposed overload contorl scheme maintains the target utilization very well under the various processor overload conditions and reduces the cell loss probability under the cell overflow conditions.

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국내 폐탄광 광산배수 자연정화처리시설의 가동현황 연구

  • 지상우;고주인;김효범;강희태;김재욱;김선준
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2003.04a
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    • pp.352-355
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    • 2003
  • 27 passive systems in 21 mines constructed by The Coal Industry Promotion Board since 1996 were investigated to evaluate the treatment efficiency of systems and find problems in each system, which will eventually lead to the improvement or suggesting the alternative method of the passive treatment system. Problems in operation include overflow, leakage, inefficiency and unusablness. The efficiency of systems which has been evaluated by metal(Fe) removal rate and/or by acidity removal rate do not reflect the poor removal rate of S $O_4$$^{2-}$. Especially high concentration of S $O_4$$^{2-}$ and high COD in the beginning of the operation would decrease the bacteria activity due to the lack of the nutrition. To solve the problem of overflow the upflow-type SAPS is being considered.

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