• Title/Summary/Keyword: stale

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A Hybrid Value Predictor using Speculative Update of the Predictor Table and Static Classification for the Pattern of Executed Instructions in Superscalar Processors (슈퍼스칼라 프로세서에서 예상 테이블의 모험적 갱신과 명령어 실행 유형의 정적 분류를 이용한 혼합형 결과값 예측기)

  • Park, Hong-Jun;Jo, Young-Il
    • Journal of KIISE:Computing Practices and Letters
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    • v.8 no.1
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    • pp.107-115
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    • 2002
  • We propose a new hybrid value predictor which achieves high performance by combining several predictors. Because the proposed hybrid value predictor can update the prediction table speculatively, it efficiently reduces the number of mispredicted instructions due to stale data. Also, the proposed predictor can enhance the prediction accuracy and efficiently decrease the hardware cost of predictor, because it allocates instructions into the best-suited predictor during instruction fetch stage by using the information of static classification which is obtained from the profile-based compiler implementation. For the 16-issue superscalar processors, simulation results based on the SimpleScalar/PISA tool set show that we achieve the average prediction rates of 73% by using speculative update and the average prediction rates of 88% by adding static classification for the SPECint95 benchmark programs.

Sepculative Updates of a Stride Value Predictor in Wide-Issue Processors (와이드 이슈 프로세서를 위한 스트라이드 값 예측기의 모험적 갱신)

  • Jeon, Byeong-Chan;Lee, Sang-Jeong
    • Journal of KIISE:Computer Systems and Theory
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    • v.28 no.11
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    • pp.601-612
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    • 2001
  • In superscalar processors, value prediction is a technique that breaks true data dependences by predicting the outcome of an instruction in order to exploit instruction level parallelism(ILP). A value predictor looks up the prediction table for the prediction value of an instruction in the instruction fetch stage, and updates with the prediction result and the resolved value after the execution of the instruction for the next prediction. However, as the instruction fetch and issue rates are increased, the same instruction is likely to fetch again before is has been updated in the predictor. Hence, the predictor looks up the stale value in the table and this mostly will cause incorrect value predictions. In this paper, a stride value predictor with the capability of speculative updates, which can update the prediction table speculatively without waiting until the instruction has been completed, is proposed. Also, the performance of the scheme is examined using Simplescalar simulator for SPECint95 benchmarks in which our value predictor is added.

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Hydrologic Performance Characteristics of Small Scale Hydro Power Site (소수력발전입지의 수문학적 성능특성)

  • Park, Wan-Soon;Lee, Chul-Hyung
    • Journal of the Korean Solar Energy Society
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    • v.27 no.3
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    • pp.135-142
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    • 2007
  • The model to predict flow duration characteristics and performance for small scale hydro power(SSHP) plants is studied to analyze the effects of rainfall condition. One existing SSHP plant was selected and performance characteristics was analyzed by using the developed model. The predicted results from the model developed show that the data were in good agreement with operational results of existing SSHP plant. The results show that both the scale parameter and the shape parameter have large effects on the performance of SSHP sites. And also it was found that the model developed in this study can be a useful tool to predict the performance of SSHP sites.

Treatment with Glucanhydrolase from Lipomyces starkeyi for Removal of Soluble Polysaccharides in Sugar Processing

  • Lee Jin-Ha;Kim Gha-Hyun;Kim Seung-Heuk;Cho Dong-Lyun;Kim Do-Won;Day Donal F.;Kim Do-Man
    • Journal of Microbiology and Biotechnology
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    • v.16 no.6
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    • pp.983-987
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    • 2006
  • The sole use of the glucanhydrolase (exhibiting both dextranase and amylase activities) from Lipomyces starkeyi hydrolyzed the soluble polysaccharides in sugar syrup more efficiently than a mixed treatment using both commercial dextranase and amylase. The glucanhydrolase treatment of stale sugar cane juice resulted in a yield of square, light-colored sugar crystals.

A Concurrency Control Mechanism Ensuring Latest-Bound Currency in Mobile Broadcasting Environments (이동 방송환경에서 최신 현행성을 보장하는 병행선 제어기법)

  • Han, Boo-Hyung;Chung, Sung-Kwon;Cho, Yoo-Kun
    • Journal of KIISE:Information Networking
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    • v.28 no.2
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    • pp.207-216
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    • 2001
  • 이동 방송 환경은 정보를 가지고 있는 서버가 다수의 이동 클라이언트에게 모든 데이터를 주기적으로 방송하면 클라이언트가 자신이 원하는 데이터가 방송 채널에 나타날 때 이를 검색하는 환경을 말한다. 이때 클라이언트가 수행하는 읽기 전용 트랜잭션은 일관적이면서도 가장 최근에 갱신된 데이터를 필요로한다. 이동 방송환경에 적합하도록 연구된 기존의 병행성 제어 기법들을 클라이언트가 일관적인 데이터를 읽는 것은 보장하지만 가장 최근에 갱신된 데이터를 읽을수 있게 하는 최신 현행성은 보장하지 못한다. 본 논문에서는 기존 기법들과 동일한 수준의 일관성뿐만 아니라 최신 현행성을 보장하는 효율적인 병행성 제어 기법을 제안하고 이를 검증한다. 아울러 제안된 기법의 성능을 평가하기 위하여 최신이 아닌 데이터를 읽은 경우(stale read)의 수와 트랜잭션 중단의 수를 각각 측정하였다. 시뮬레이션을 통한 실험결과 본 논문에서 제안하는 기법은 기존의 방법과 비교할 때 항상 최신의 데이터를 읽으면서 트랜잭션중단의 수를 감소시킨다는 것을 알수 있었다.

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A Hybrid Value Predictor Using Static Classification (정적 분류를 이용한 혼합형 결과간 예측기)

  • 박홍준;고광현;조영일
    • Proceedings of the Korean Information Science Society Conference
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    • 2001.10c
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    • pp.865-867
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    • 2001
  • 데이터 종속성을 제거하기 위해서 명령어의 결과값을 예상하는 여러 결과값 예측기의 장점을 이용하여 놓은 성능을 얻을 수 있는 새로운 혼합형 예측 메커니즘을 제안한다. 제안된 혼합형 결과값 예측기는 예상 테이블을 모험적으로 갱신할 수 있기 때문에 부적절한(Stale) 데이터로 인해 잘못 예상되는 명령어의 수를 효과적으로 감소시킨다. 또한 정적 분류 정보를 사용하여 명령의 반입시 적절한 예측기에 할당함으로써 예상 정확도를 더욱 향상시키며, 하드웨어 비용을 효율적으로 감소시키도록 하였다. 5개의 SPECint 95 벤치마크 프로그램에 대해 SimpleScalar/PISA 3.0 툴셋을 사용하여 실험하였다. 16-이슈 폭에서 모험적 갱신을 사용한 평균 예상 정확도는 73%의 실험 결과가 나왔으며, 정적 분류 정보를 사용하였을 경우 예상 정확도가 88%로 증가된 결과를 얻었다.

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A Cooperation Model for Object Sharing in Distributed Systems (분산시스템에서 객체공유를 위한 상호협력모델)

  • 정진섭;윤인숙;이재완
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 1999.05a
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    • pp.224-229
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    • 1999
  • In distributed object oriented environment based upon wide heterogeneous network, effective cooperation policies between/among distributed objects are needed to resolve a complexity of management of distributed objects because of growing of a large stale of systems. Thus, in this paper, we propose three trading cooperation models between/among traders for supporting a high speed and a wide selection of trader service for clients, by considering three different cooperation models(light weight trader, simple negotiation and federation) depending upon their facilities, goals, and weights of goals.

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The Verification of Case Study and the Construction of Fault Management System of Electrical Facilities through FMEA Method (FMEA기반 전기설비 사고처리시스템 구축 및 사고사례 검증)

  • Kim, Young-Seok;Shong, Kil-Mok;Kim, Sun-Gu
    • Proceedings of the KIEE Conference
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    • 2009.04a
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    • pp.315-317
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    • 2009
  • When happen the electrical facilities accident, the one's diagnosis system of fault cause was constructed by FMEA method. From the verification of system, the one's diagnosis system agreed well with result that analyzed actual stale. Thus, the system is judged to be used effectively examine for accident cause of electrical facilities.

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Design of Pulse Shaping Filter for High-Speed Service in Digital Satellite Broadcasting System (디지털 위성방송 시스템의 고속 서비스를 위한 Pulse Shaping Filter 설계)

  • 오재현;이인섭;이완범;강정용;박형근;김환용
    • Proceedings of the IEEK Conference
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    • 2002.06b
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    • pp.337-340
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    • 2002
  • In data transmission at the digital satellite broadcasting systems, the delay and spread are caused whit receiving original signals from the transmitter in the receiver. So, there are some problems in data fast transmission. Also, transmitted signals ate received in stale of the combination of transmission delay and noise of channel. The affect of channel noise is reduced when increasing transmission power, but as signal interference due to the transmission delay and spread of channel increase in proportion to the transmission power, there is a problem in spite of increasing the transmission power. And there is the problem to add ISI(inter symbol interference) because the property of the channel is limo-varying due to relative moving in the transceiver Therefore, in this paper, a pulse shaping filter for the high-speed service in digital satellite broadcasting systems was designed and reduced the ISI.

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Control of Coupled Tank Level using GA-SMC (GA-SMC를 이용한 이중 탱크의 정밀한 수위 제어)

  • 박현철;지석준;정종원;최우진;이준탁
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2002.05a
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    • pp.239-244
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    • 2002
  • Even though, tanks are used at the many industry plants, it is very difficult to control the tank level without any overflow and shortage; moreover, cause of its complication of dynamics and nonlinearity, it's impossible to realize the accurate control using the mathematical model which can be applied to the various operation modes. However, the sliding mode controller(SMC) is known as having the robust variable structures for the nonlinear control systems with the parametric perturbations and with the sudden disturbances, but the auto-tuning of parameters was a problem. Therefore, in this paper, a Genetic Algorithm based Sliding Mode Controller (GA-SMC) for the precise control of the coupled tank level was tried. GA optimized the SMCs switching parameters easily and rapidly. The simulation results are shown that the tank level could be satisfactorily controlled with less overshoot and steady-stale error by the proposed GA-SMC.

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