Browsing by Author "Lee, WY"

Now showing 1 - 9 of 9

An effictive and efficient hierarchical fuzzy rule based classifier
(2003)
Tsai, CH
;
Lin, SY
;
Cheng, MH
;
Horng, SC
;
Liu, CH
In this paper, we propose a hierarchical fuzzy rule based classifier (HFRBC) for the classification problem with large number of classes and continuous attributes. A hierarchical clustering concept is introduced to achieve a finer fuzzy partition. Critical attributes are used to perform the cluster splitting and generate a cluster splitting tree. The effective attributes for the terminal clusters in the cluster splitting tree are picked so as to reduce the size of the fuzzy-rule set and hence reduce the computational complexity. The fuzzy rule generation procedures and classification procedures of the proposed HFRBC are simple and easily implemented. We have successfully applied the HFRBC to the classification problem of the working wafers in an ion implanter.
Analysis of a liquid crystal Fabry-Perot etalon filter: A novel model
(1997-04-01)
Chen, PL
;
Lin, KC
;
Chuang, WC
;
Tzeng, YC
;
Lee, KY
The authors propose a novel analysis method to investigate the characteristics of an electrically tunable liquid-crystal Fabry-Perot interferometer (LC-FPI), Based on the solution of deformation analysis of liquid crystal in an electric field and the assumption of small refractive index variation in the Fabry-Perot cavity, the voltage-dependent equivalent refractive index of the cavity has been derived. Tuning behaviors of the LC-FPI filter were simulated by means of the dependence, The calculated result and the experimental measured data agree well with each other.
Analysis of a liquid crystal Fabry-Perot etalon filter: A novel model
(1997-04-01)
Chen, PL
;
Lin, KC
;
Chuang, WC
;
Tzeng, YC
;
Lee, KY
The authors propose a novel analysis method to investigate the characteristics of an electrically tunable liquid-crystal Fabry-Perot interferometer (LC-FPI), Based on the solution of deformation analysis of liquid crystal in an electric field and the assumption of small refractive index variation in the Fabry-Perot cavity, the voltage-dependent equivalent refractive index of the cavity has been derived. Tuning behaviors of the LC-FPI filter were simulated by means of the dependence, The calculated result and the experimental measured data agree well with each other.
Clustering-based hierarchical radiosity for dynamic environments
(1999-11-01)
Lee, WY
;
Chuang, JH
;
資訊工程學系
;
Department of Computer Science
This paper extends hierarchical radiosity and clustering techniques to dynamic environments, in which dynamic manipulations, such as repositioning an object and changing surface attributes, are repeatedly applied. The cluster techniques can be effective in reducing the computational complexity of both initial linking creation and link updating of dynamic manipulations. When the object is repositioned in a dynamic environment, the affected links, both energy and cluster links, can be identified rapidly by means of our proposed new strategy. As,the total net energy of the environment is decreased, we exploit the so-called history links to un-refine the affected patches. An effective progressive refinement strategy is also applied to further avoid the creation of unnecessary links.
Effective meshing and form factor calculation for accurate progressive radiosity
(2004)
Lee, WY
;
Chuang, JH
;
資訊工程學系
;
Department of Computer Science
In this paper two effective methods are proposed to address two inaccuracies, deficient meshing and error-prone form factors, respectively, in the context of progressive radiosity. The first one addresses the meshing problem using an automatic adaptive subdivision that takes the radiosity difference, the radiosity residual, and the visibility information as error estimates. The second method employs a hybrid form-factor evaluation recursively combining an approximation to the analytic point-to-disk form factor and an accurate form factor from a differential area to a convex polygon. Finally, we demonstrate the effectiveness and practicability of the proposed methods by testing with a set of global illumination test scenes to show the experimental results qualitatively and quantitatively.
Effects of gamma radiation on optical fibre sensors
(2004-02-01)
Lin, KC
;
Lin, CJ
;
Lee, WY
;
光電工程學系
;
Department of Photonics
Consideration of thermo-optic coefficients is essential in the applications of optical fibre sensors and high-speed fibre communication systems. The Fabry-Perot interference method is applied to study these coefficients of four types of commercial fibres. The results are in agreement with the values calculated from the Sellmeier equation for fused silica fibre, with a difference of only about 0.2% for the Coming single-mode fibre SMF-28. In order to apply fibre sensors to a high-radiation environment, the thermo-optic coefficients for these fibres have been investigated after exposure to heavy doses of gamma radiation, and their radiation resistance has been studied.
Evaluation of modulating field of photoreflectance of surface-intrinsic-n(+) type doped GaAs by using photoinduced voltage
(2002-04-01)
Lee, WY
;
Chien, JY
;
Wang, DP
;
Huang, KF
;
Huang, TC
Photoreflectance (PR) of surface-intrinsic-n(+) type doped GaAs has been measured for various power densities of pump laser. The spectra exhibited many Franz-Keldysh oscillations, whereby the strength of electric field F in the undoped layer can be determined. The thus obtained Fs are subject to photovoltaic effect and are less than built-in field F-bi. In the previous work we have obtained the relation Fapproximate toF(bi)-deltaF/2 when deltaF
Fault detection and isolation for plasma etching using model-based approach
(2003)
Cheng, MH
;
Huan-Shin, L
;
Lin, SY
;
Liu, CH
;
Lee, WY
A fault detection and isolation system using model-based approach for the chamber pressure of plasma etching is developed. The dynamics of chamber pressure is modeled as a linear multiple-input-single-output closed-loop system and the model parameters are extracted by the system identification technique. The obtained parameters are then converted to physically meaningful features for detecting and isolating faults. The fuzzy inference and Dempster-Shafer evidence combining techniques are employed to detect and isolate fault from the features. The system has been evaluated by the measured data that are collected via SECS-II from the employed Lam-490 plasma etcher for processing practical products. The test results are satisfactory for a large amount of practical data and extensive computer simulations.
Reducing the overkills and retests in wafer testing process
(2003)
Horng, SC
;
Lin, SY
;
Cheng, MH
;
Yang, FY
;
Liu, CH
Reducing overkills is one of the main objectives in wafer testing process, however the major mean to prevent overkills is retest. In this paper, we formulate the problem of reducing overkills and retests as a stochastic optimization problem to determine optimal threshold values concerning the number of good dies and the number of bins in a lot and wafer to decide whether to go for a retest after a regular wafer probing. The considered stochastic optimization problem is an NP hard problem. We propose an Ordinal Optimization theory based two-level method to solve the problem for good enough threshold values to achieve lesser overkills and retests within a reasonable computational time. Applying to a case based on the true mean of bins of a real semiconductor product, the threshold values we obtained are the best among 1000 sets of randomly generated threshold values in the sense of lesser overkills under a tolerable retest rate.