• 제목/요약/키워드: computation

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사각덕트 내에서 원형 실린더 주위의 강제대류 열전달에 대한 실험과 수치계산에 관한 연구 (Study on the Experiment and Numerical Computation of Forced Convection Heat Transfer around Circular Cylinder in a Rectangular Duct)

  • 윤영환;김경환
    • 설비공학논문집
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    • 제16권5호
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    • pp.490-498
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    • 2004
  • This paper measures the forced convective heat transfer from heated cylinder to air flow in a rectangular duct at Re$_{D}$ =2,337, 4,589, 6,621 and 7,944 through experiments. And the heat transfer is computed by 3-D numerical computation in which various turbulent models are applied. It is shown through the comparison of experimental and computed data that numerical computation with standard k-$\varepsilon$ model predicts the experimental data most accurately. Furthermore, the correlation from the computed heat transfer is almost similar to that from the experiment when Re$_{D}$ is greater than 4,589. In addition, the correlation of McAdams is the closest to that from experimental data among various correlations from literature in the range of Reynolds number.ber.

Comparison of Monte Carlo Simulation and Fuzzy Math Computation for Validation of Summation in Quantitative Risk Assessment

  • Im, Myung-Nam;Lee, Seung-Ju
    • Food Science and Biotechnology
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    • 제16권3호
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    • pp.361-366
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    • 2007
  • As the application of quantitative risk assessment (QRA) to food safety becomes widespread, it is now being questioned whether experimental results and simulated results coincide. Therefore, this paper comparatively analyzed experimental data and simulated data of the cross contamination, which needs summation of the simplest calculations in QRA, of chicken by Monte Carlo simulation and fuzzy math computation. In order to verify summation, the following basic operation was performed. For the experiment, thigh, breast, and a mixture of both parts were preserved for 24 hr at $20^{\circ}C$, and then the cell number of Salmonella spp. was measured. In order to examine the differences between experimental results and simulated results, we applied the descriptive statistics. The result was that mean value by fuzzy math computation was more similar to the experimental than that by Monte Carlo simulation, whereas other statistical descriptors by Monte Carlo simulation were more similar.

Automatic Speech Database Verification Method Based on Confidence Measure

  • Kang Jeomja;Jung Hoyoung;Kim Sanghun
    • 대한음성학회지:말소리
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    • 제51호
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    • pp.71-84
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    • 2004
  • In this paper, we propose the automatic speech database verification method(or called automatic verification) based on confidence measure for a large speech database. This method verifies the consistency between given transcription and speech using the confidence measure. The automatic verification process consists of two stages : the word-level likelihood computation stage and multi-level likelihood ratio computation stage. In the word-level likelihood computation stage, we calculate the word-level likelihood using the viterbi decoding algorithm and make the segment information. In the multi-level likelihood ratio computation stage, we calculate the word-level and the phone-level likelihood ratio based on confidence measure with anti-phone model. By automatic verification, we have achieved about 61% error reduction. And also we can reduce the verification time from 1 month in manual to 1-2 days in automatic.

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능동소음제어를 위한 IIR 구조 2차경로 추정 알고리즘 (IIR Structure Secondary Path Estimation Algorithms for Active Noise Control Systems)

  • 최영훈;안동준;남현도
    • 조명전기설비학회논문지
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    • 제25권2호
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    • pp.143-149
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    • 2011
  • In this paper, IIR structures are proposed to reduce the computation complexity of the secondary-pass estimation in active noise control(ANC) systems. However, there are stability problems of using IIR models to reduce the computation complexity in ANC systems. To overcome these problems, we propose a stabilizing procedure of recursive least mean squares (RLMS) algorithms for eatimating the parameters of IIR models of the secondary path transfer functions. The multichannel ANC systems are implemented by using the TMS320C6713 DSP board to test the performance of computation complexity and stability of the proposed methods. Comparing the IIR filters with the FIR filters, the IIR filters can reduce 50[%] of the computation and obtain similar noise reduction result.

GMDH를 이용한 비선형 시스템의 모델링 성능 개선 (Performance Improvement of Nonlinear System Modeling Using GMDH)

  • 홍연찬
    • 한국정보통신학회논문지
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    • 제14권7호
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    • pp.1544-1550
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    • 2010
  • 비선형 동적 시스템을 모델링하기 위해 GMDH(Group Method of Data Handling)를 적용한 많은 연구들이 수행되어 왔다. 그러나 모델링의 정확성을 위해서는 계산량이 크게 증가한다. 그러므로 본 논문에서는 입력 데이터를 취사선택하는 기준을 점감적으로 조정함으로써 적어도 정확성을 유지하면서 전형적인 GMDH의 단점인 과도한 계산을 피할 수 있는 방법을 제안한다. 컴퓨터 시뮬레이션 결과, GMDH 알고리듬의 계산량을 성공적으로 줄일 수 있었고 에러율도 소폭 줄일 수 있었다.

ODC 클럭 게이팅을 이용한 저전력 Interface 회로설계 (Design of Low- Power Interface using Clock Gating Based on ODC Computation)

  • 양현미;김희석
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2008년도 하계종합학술대회
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    • pp.597-598
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    • 2008
  • In this paper, a sample design of I/O port of micro-processor using ODC(Output Don't Care) computation that is one of methods for Clock Gating applicable at the register transfer level(RTL). The ODC computation Method is applied at the point that estimate the value considering Don't Care Conditions from output of datapath to registers using clock in logic system. This paper also shows the results of reduce consumption power due to controlling clock that was supplied at registers. In Experimental results, ODC computation Method reduce power reductions of around 37.5%

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1차원 및 2차원 이산 웨이브렛 변환 계산을 위한 새로운 시스톨릭 어레이 (New systolic arrays for computation of the 1-D and 2-D discrete wavelet transform)

  • 반성범;박래홍
    • 전자공학회논문지S
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    • 제34S권10호
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    • pp.132-140
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    • 1997
  • This paper proposes systolic array architectures for compuataion of the 1-D and 2-D discrete wavelet transform (DWT). The proposed systolic array for compuataion of the 1-D DWT consists of L processing element (PE) arrays, where the PE array denotes the systolic array for computation of the one level DWT. The proposed PE array computes only the product terms that are required for further computation and the outputs of low and high frequency filters are computed in alternate clock cycles. Therefore, the proposed architecuter can compute the low and high frequency outputs using a single architecture. The proposed systolic array for computation of the 2-D DWT consists of two systolic array architectures for comutation of the 1-D DWT and memory unit. The required time and hardware cost of the proposed systolic arrays are comparable to those of the conventional architectures. However, the conventional architectures need extra processing units whereas the proposed architectures fo not. The proposed architectures can be applied to subband decomposition by simply changing the filter coefficients.

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사각덕트내의 유체유동에 관한 수치계산과 실험의 비교 (The comparison between Numerical Computation and Experiment on Fluid Elow in Rectangular Duct)

  • 윤영환;배택희;박원구
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2002년도 학술대회지
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    • pp.71-74
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    • 2002
  • Fluid flow in a rectangular duct system are measured by W laser doppler velocity meter, and also computed by commercial software of STAR-CD for comparison between then First, for a rectangular duct with 90 degree metered elbow, the fluid flow with Reynolds numbs's of 1,508 is predicted by assumption of both laminar and turbulent models. But, even though the Reynolds number is less than 2,300-3,000, the computation by turbulent model is close to the experimental data. Moeover, the computation by turbulent model for Reynolds number of 11,751 also predicts the experimental data satisfactorily. Second, for a rectangular duct with two branch ducts, the ratios between flow rates in the two branches are invariant to Reynolds number according to both of numerical and experimental results.

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배경회전하에서 형성되는 주기적 유동의 3차원 수치해석과 실험 (Three-Dimensional Numerical Computation and Experiment on Periodic Flows under a Background Rotation)

  • 서용권;박재현
    • 대한기계학회논문집B
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    • 제27권5호
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    • pp.628-634
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    • 2003
  • We present numerical and experimental results of periodic flows inside a rectangular container under a background rotation. The periodic flows are generated by changing the speed of rotation periodically so that a time-periodic body forces produce the unsteady flows. In numerical computation, a parallel-computation technique with MPI is implemented. Flow visualization and PIV measurement are also performed to obtain velocity fields at the free surface. Through a series of numerical and experimental works, we aim to clarify, if any, the fundamental reasons \ulcornerf discrepancy between the two-dimensional computation and the experimental measurement, which was detected in the previous study for the same flow model. Specifically, we check if the various assumptions prerequisite for the validity of the classical Ekman pumping law are satisfied for periodic flows under a background rotation.

Fully Verifiable Algorithm for Secure Outsourcing of Bilinear Pairing in Cloud Computing

  • Dong, Min;Ren, Yanli;Zhang, Xinpeng
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제11권7호
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    • pp.3648-3663
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    • 2017
  • With the development of cloud computing and widespread availability of mobile devices, outsourcing computation has gotten more and more attention in cloud computing services. The computation of bilinear pairing is the most expensive operation in pair-based cryptographic schemes. Currently, most of the algorithms for outsourcing bilinear pairing have small checkability or the outsourcers need to operate expensive computations. In this paper, we propose an efficient algorithm for outsourcing bilinear pairing with two servers, where the outsourcers can detect the errors with a probability of 1 if the cloud servers are dishonest, and the outsourcers are not involved in any complex computations. Finally, the performance evaluation demonstrates that the proposed algorithm is most efficient in all of fully verifiable outsourcing algorithms for bilinear pairing.