A new method for solving broadband matching problems

In this paper, a new approach based on the real frequency technique (RFT) has been proposed to solve broadband matching problems using cascaded unequal length transmission lines. At the end of the design process, optimum characteristic impedance and delay values of transmission lines are obtained. Two examples are given to illustrate the utilization of the proposed approach.

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Reduced-Degrees-of-Freedom Gaussian-Mixture-Model Fitting for Large-Scale History-Matching Problems

SPE Journal ◽

10.2118/193916-pa ◽

2019 ◽

Vol 25 (01) ◽

pp. 037-055

Author(s):

Guohua Gao ◽

Hao Jiang ◽

Chaohui Chen ◽

Jeroen C. Vink ◽

Yaakoub El Khamra ◽

...

Keyword(s):

Gaussian Mixture Model ◽

Mixture Model ◽

History Matching ◽

Degrees Of Freedom ◽

Large Scale ◽

Computational Cost ◽

Gaussian Mixture ◽

New Method ◽

Matching Problem ◽

Matching Problems

Summary It has been demonstrated that the Gaussian-mixture-model (GMM) fitting method can construct a GMM that more accurately approximates the posterior probability density function (PDF) by conditioning reservoir models to production data. However, the number of degrees of freedom (DOFs) for all unknown GMM parameters might become huge for large-scale history-matching problems. A new formulation of GMM fitting with a reduced number of DOFs is proposed in this paper to save memory use and reduce computational cost. The performance of the new method is benchmarked against other methods using test problems with different numbers of uncertain parameters. The new method performs more efficiently than the full-rank GMM fitting formulation, reducing the memory use and computational cost by a factor of 5 to 10. Although it is less efficient than the simple GMM approximation dependent on local linearization (L-GMM), it achieves much higher accuracy, reducing the error by a factor of 20 to 600. Finally, the new method together with the parallelized acceptance/rejection (A/R) algorithm is applied to a synthetic history-matching problem for demonstration.

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A new reflection coefficient modulus method for broadband matching problems

Microwave and Optical Technology Letters ◽

10.1002/mop.11335 ◽

2003 ◽

Vol 40 (3) ◽

pp. 221-224

Author(s):

Tao Su ◽

Changhong Liang ◽

Yan Shi

Keyword(s):

Reflection Coefficient ◽

Matching Problems ◽

Modulus Method ◽

Broadband Matching

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Selective Sampling and Orientation of Non-Homogeneous Tissues

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100238 ◽

1968 ◽

Vol 26 ◽

pp. 98-99

Author(s):

C. C. Clawson ◽

L. W. Anderson ◽

R. A. Good

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Light Microscopy ◽

Random Sampling ◽

New Method ◽

Microscope Examination ◽

Small Areas ◽

Selective Sampling ◽

Large Numbers ◽

Specific Orientation

Investigations which require electron microscope examination of a few specific areas of non-homogeneous tissues make random sampling of small blocks an inefficient and unrewarding procedure. Therefore, several investigators have devised methods which allow obtaining sample blocks for electron microscopy from region of tissue previously identified by light microscopy of present here techniques which make possible: 1) sampling tissue for electron microscopy from selected areas previously identified by light microscopy of relatively large pieces of tissue; 2) dehydration and embedding large numbers of individually identified blocks while keeping each one separate; 3) a new method of maintaining specific orientation of blocks during embedding; 4) special light microscopic staining or fluorescent procedures and electron microscopy on immediately adjacent small areas of tissue.

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