The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform

Te Tan Liao - One of the best experts on this subject based on the ideXlab platform.

  • Skew Ray tracing and error analysis of optical lens with cylindrical boundary surface
    Transactions of the Canadian Society for Mechanical Engineering, 2009
    Co-Authors: Te Tan Liao, Kuo Ying Chen, Shih Hung Chen, Chun-ta Chen
    Abstract:

    This study applies computational geometric algebra based on a 4|4 homogeneous transformation matrix and Snell's law of geometrical optics to analyze skew Rays and the errors of a light Ray's path as it passes through a cylindrical lens. The author addresses two important topics: (1) the determination of the direction of a reflected or Refracted Ray by Snell's law and (2) the expression of the combination of two principal sources of light path error using error analysis. In topic (2), one of the sources is the translational errors ?dix, ?diy, and ?diz and the rotational errors ? ?ix, ? ?iy, and D?iz that determine the deviation of the light path at each boundary surface, while the other source is the differential changes induced in the incident point position and the unit directional vector of the Refracted/reflected Ray as a result of differential changes in the position and unit directional vector of the light source. The methodology presented in this study provides a comprehensive and robust approach for evaluating the error of a light Ray path as it passes through a cylindrical lens. Copyright � 2009 Springer Science+Business Media B.V.

  • Analysis of optical elements with flat boundary surfaces
    Applied Optics, 2003
    Co-Authors: Te Tan Liao
    Abstract:

    Optical systems are currently evaluated by use of Ray-tracing techniques to extract performance quantities such as aberration and spot size. To improve on the use of optical equations, we formulate various important optical functions using a 4 × 4 homogeneous transformation matrix to design and analyze skew Rays that cross flat optical boundary surfaces. We address three important topics: (1) the direction of a reflected or Refracted Ray is determined according to Snell’s law, (2) sensitivity analysis expresses differential changes of reflected or Refracted Rays in terms of differential changes of incident Rays, and (3) aberration of polychromatic light is presented analytically. A solid-glass corner cube and a Pechan prism are used to demonstrate the validity of the developed methodology.

Eunseok Bang - One of the best experts on this subject based on the ideXlab platform.

  • mean Refracted Ray path method for reliable downhole seismic data interpretations
    Soil Dynamics and Earthquake Engineering, 2014
    Co-Authors: Eunseok Bang
    Abstract:

    Abstract The downhole seismic method is one of the most widely used field seismic methods because it is cost-effective and simple to operate compared to other borehole methods. For the interpretation of the data, the direct method is generally used, but this method determines the VS profile roughly and requires an interpreter׳s subjective interpretation. To evaluate the VS profile in detail, the Refracted Ray path method is used. However, the VS profiles evaluated by these methods often show meaningless repetitive fluctuations with depth and it is because the estimated travel time data is somewhat inaccurate. In this paper, the mean Refracted Ray path method (MRM), which combines the advantages of both the direct method and the Refracted Ray path method, is proposed. It provides the VS profile more reliably and automatically. The travel time data is corrected based on the Refracted Ray path and the R2 value of the regression curve is employed for automation. To verify the proposed method, the synthetic travel time data were generated by forward modeling based on Snell׳s law with some amount of random error added. As the amount of random error increased, the meaningless repetitive fluctuations in the VS profile determined by the conventional methods also increased. On the other hand, the VS profiles determined by the MRM matched the model well and the superiority of the proposed method was thus noted. Finally, the proposed method was applied for the data reduction of several instances of field data. The determined VS profiles were compared with the drilling logs, the SPT-N values, and/or the CPT result, and the reliability and applicability of the MRM was thus verified.

  • Improvement of Data Interpretation Method for Downhole Seismic Method
    2007
    Co-Authors: Eunseok Bang
    Abstract:

    Mean Refracted Ray path method (MRM) which is combined the advantage of direct method and Refracted Ray path method is proposed. It can provide reasonable VS profile automatically considering travel time measurement error. The overall procedure of MRM is similar to the direct method. However, corrected travel time data is based on the result of Refracted Ray path method for considering Refracted Ray path and the R value of regression curve is employed for automation. According to the R value, soil model is constructed and VS value of each layer is evaluated from the slope of regression curve at each divided layer automatically by programmed routine. The reliability and applicability of the proposed method was verified by using numerical and field study.

M. Ali Ak - One of the best experts on this subject based on the ideXlab platform.

  • AN ANALYTICAL RayPATH APPROACH TO THE REFRACTION WAVEFRONT METHOD1
    Geophysical Prospecting, 1990
    Co-Authors: M. Ali Ak
    Abstract:

    Seismic refraction surveying is still an important tool for determining the geometries and elastic wave propagation velocities of near-surface layers. Many analytical and graphical methods have been developed over the years for refraction interpretation, and these can be classified into two basic groups. The first group visualizes critically Refracted Rays converging on a common surface position, while the second group, which includes the wavefront methods, makes use of the critical Rays emerging from a common point on the refractor. The method described in this paper is an analytical approach to the wavefront methods. The reverse Refracted Ray received by a geophone is intersected by the forward Refracted Rays received by subsequent geophones and a common critical refraction point on the refractor is estimated after a series of comparisons. This process is repeated for each geophone to yield the geometry and the velocity of the refractor. Several interpolations are performed to achieve a better accuracy. Palmer's models are used to test the efficiency of the algorithm. The results are presented together with those of other methods applied to the same models.

  • An analytical Raypath approach to the refraction wavefront method
    1990
    Co-Authors: M. Ali Ak
    Abstract:

    An algorithm for refraction interpretation is described. The reverse Refracted Ray received by a geophone is intersected by the forward Refracted Rays received by subsequent geophones and a common critical refraction point on the refractor is estimated after a series of comparisons. This process is repeated for each geophone to yield the geometry and the velocity of the refractor. Several interpolations are performed to achieve a better accuracy. The algorithm is tested using Palmer's models

Ruey-jen Yang - One of the best experts on this subject based on the ideXlab platform.

  • Two optofluidic devices for the refractive index measurement of small volume of fluids
    Microfluidics and Nanofluidics, 2012
    Co-Authors: Kuo-sheng Chao, Ruey-jen Yang
    Abstract:

    Two simple optofluidic devices based on a microprism and a refraction channel, respectively, are proposed for measuring the refractive index of fluids. The microprism chip consists of an optical waveguide channel and a single triangular chamber filled with the test fluid, while the refraction channel chip consists of a single turning channel which functions as a liquid-core/solid-cladding optical waveguide. In both chips, the refractive index of the test fluid is calculated from a CCD image of the Refracted Ray in accordance with simple geometrical optics principles. The experimental results show that the refraction channel chip provides a more accurate measurement performance than the microprism chip; particularly for colloidal samples. However, the refraction channel chip is suitable only for the measurement of fluids with a refractive index greater than that of the chip substrate. Overall, the results presented in this study show that both devices provide a simple, low cost and effective means of determining the refractive index of a wide range of common test fluids with nano-liter volume.

Maria C. Simon - One of the best experts on this subject based on the ideXlab platform.