Browsing by Author "Cheng, MH"

Now showing 1 - 20 of 20

A new adaptive notch filter with constrained poles and zeros using Steiglitz-McBride method
(1998)
Cheng, MH
;
Tsai, JL
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper we present a new adaptive notch filter (ANF) using the well-known Steiglitz-McBride method (SMM) [1] for an IIR filter with the constrained poles and zeros. The proposed ANF, termed as SMM-ANF, converges to the unbiased solution, has fast convergence speed, and requires less computational complexity than existing recursive maximum likelihood adaptive notch filters (RML-ANF) [2]. In the stationary environments, we analyze SMM-ANF convergence properties using the ordinary differential equation (ODE) [4] technique; we derive conditions for the SMM-ANF convergence solution unbiased. Simulations further display that SMM-ANF has better resolution in identifying frequencies of multiple sine waves than RML-ANF. In the nonstationary environments, we also show that SMM-ANF and RML-ANF have approximately identical tracking performance. Simulations are also done to verify the theoretically derived results.
A new IIR adaptive notch filter
(2006-07-01)
Cheng, MH
;
Tsai, JL
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A new IIR adaptive notch filter (ANF) with fast convergence rate, accurate estimation of notch frequencies, and modest realization complexity is presented in this paper. The problem of obtaining a notch filter from a given signal containing multiple sine waves in noise is first formulated as the conventional problem of system identification. Then the new ANF is developed via the algorithm of Steiglitz McBride. Extensive simulations have been performed to verify the effectiveness of the ANF. (C) 2005 Elsevier B.V. All rights reserved.
Alternating coordinates minimization algorithm for estimating parameters of partial erasure plus transition shift model
(2004-07-01)
Kao, TS
;
Cheng, MH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The identification of model parameters of a high-density recording channel is usually difficult and complicated. In this paper, we successfully apply the alternating coordinates minimization (ACM) algorithm for estimating parameters of a partial erasure plus transition shift model (PETSM). The resulting algorithm turns out to iteratively solve two least square problems and is guaranteed to converge. Furthermore, the obtained model for a nonlinear partial response channel is more accurate than conventional models such that the maximum likelihood (ML) detector has better bit error rate (BER) performance without increasing its realization complexity. Computer simulations show that the ACM algorithm can accurately estimate the model parameters and the BER for the detector is significantly improved especially when the transition shift parameter is large.
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.
Characterization of soft rocks in Taiwan
(2000)
Huang, AB
;
Liao, JJ
;
Pan, YW
;
Cheng, MH
;
Hsieh, SY
A research project was carried out to enhance our capabilities in establishing the engineering properties of the weak sedimentary rocks in northern and central regions of Western Taiwan. Improved field sampling and testing techniques were developed and a series of in situ and laboratory experiments were performed. These included modifications of rock coring procedure, field pressuremeter, PS logging, Lugeon tests and laboratory triaxial tests. A test site was developed where rock cores were taken and a series of field experiments performed. The results from the field and laboratory experiments were analyzed and compared. An interpretation procedure in establishing the rock properties was proposed. This paper describes the experience gained in this series of experiments and discusses its implications in the characterization of the soft rocks.
Conformational conversion and local packing of cyclic olefin copolymers
(2000-12-12)
Chu, PPJ
;
Cheng, MH
;
Huang, WJ
;
Chang, FC
;
應用化學系
Cyclic olefin copolymer (COC, poly(norbornene-co-ethylene)) catalyzed by ansa-ethylenebis-(indenyl)zirconium dichloride (Et[Ind](2)ZrCl2)/methylaluminoxane (MAO) gives rise to phenomenal increase of T-g upon annealing. Unaveraged solid-state C-13 NMR resonance of the CH carbons in the norbornene (53 and 49 ppm) evidenced the conformation conversion from T[X]T and G[M]G to more stable T[X]G conformers (where [X] = [T] or [G] represent the norbornene chain conformation). As the persistent length increases with the conversion, local packing of the rigid chain subsequently occurs. Synchrotron source X-ray diffraction provides clear evidence of the averaged interchain contraction from 12.0 to 8.5 Angstrom and a tighter distribution in the spacing after annealing. In the preannealed state, T-1p(H) relaxation time revealed both mobile (where conformer converts) and rigid components (where conformation is frozen), which coalesce into a further rigid component after extended annealing. The mechanisms governing the packing in amorphous COC are likely by the random chain diffusion and not from cooperative motion as described by the bundle-packing model.
Design and analysis of a growable multicast ATM switch
(2000-07-01)
Wang, KC
;
Cheng, MH
;
資訊工程學系
;
Department of Computer Science
This work designs and analyzes a cost-effective growable multicast asynchronous transfer mode (ATM) switch that has a new grouping network structure. The proposed switch can easily be enlarged by using more stages, since both cell routing and contention resolution are designed to distribute ol er switch elements. Experimental results indicate that, by allowing valid cells to enter grouping networks from two directions (the west and north sides), the modular ATM sa itch proposed herein not only meets the ATM performance requirements for both unicasting and multicasting but also uses fen er switch elements and has a shorter cell delay than the ATM switch.
Developments in the characterization of soft rocks in Taiwan
(2003)
Huang, AB
;
Liao, JJ
;
Pan, YW
;
Cheng, MH
;
土木工程學系
Local Experience has indicated that the weak sedimentary rocks in northern and central regions of Western Taiwan were poorly cemented. Sampling in these types of rock formations has been difficult and test results on recovered samples were often scattered. The authors have been developing improved field sampling and testing techniques to enhance our capabilities in characterizing the soft rocks. These included modifications of rock coring procedure, development of a high stress pressuremeter, a borehole testing device, and laboratory triaxial tests with local strain measurements. These techniques have been applied for various construction and research projects. The paper describes the development of these new or modified techniques and experience gained in the characterization of the soft rocks in this region.
Digital image translational and rotational motion stabilization using optical flow technique
(2002-02-01)
Chang, JY
;
Hu, WF
;
Cheng, MH
;
Chang, BS
;
電控工程研究所
This paper proposes a new digital image stabilization (DIS) systems based on optical flow technique. Unlike previous DIS systems developed mainly for removing the translational motion disturbance, the proposed system removes not only the translational but also the rotational motion disturbances. A computational scheme that facilitates the local motion vector field to estimate the global disturbing translational and rotational motions is developed. First, the optical flow technique is used to estimate the local motion vector field of the image, yielding the velocity of each pixel in the current image frame. Then, the global translational and rotational motion parameters are determined in terms of the least squares estimation. Finally, these motion vectors are used to generate the counterbalance signals for removing the disturbance motion. Owing to the additional ability of the rotational motion removal, the new DIS system suppresses the undesirable translational and rotational disturbances effectively and thus enhances the DIS performance significantly.
Expectation and maximization algorithm for estimating parameters of a simple partial erasure model
(2003-01-01)
Kao, TS
;
Cheng, MH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The identification of the model parameters of a high-density recording channel generally requires solution of nonlinear equations. In this paper, we apply the expectation and maximization (EM) algorithm to realize the maximum likelihood estimation of the parameters of a simple partial erasure model, including the reduction parameters and the isolated transition response. The algorithm that results from this approach iteratively solves two least-squares problems and, thus, realization is simple. Computer simulations verify the feasibility of the EM algorithm, and show that the proposed algorithm has fast convergence and the resulting estimator is asymptotically efficient.
Fast IMDCT and MDCT algorithms - A matrix approach
(2003-01-01)
Cheng, MH
;
Hsu, YH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a systematic investigation of the modified discrete cosine transform/inverse modified discrete cosine transform (MDCT/IMDCT) algorithm using a matrix representation. This approach results in new understanding of the MDCT/IMDCT, enables,the development of new algorithms, and makes clear the connection between the algorithms. We represent in a matrix form the IMDCT as the product of the type-IV DCT with simple scaling, sign-changing, and permutation operations such that fast algorithms for the type-IV DCT can be simply modified for the IMDCT, and vice versa. Then, the simple symmetry and inversion properties of the type-IV DCT are used to develop new algorithms and establish the connection between existing fast IMDCT algorithms. This approach also enables us to show that MDCT and IMDCT share common core operation and present an efficient architecture for implementing both the MDCT and the IMDCT in one hardware.
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.
Generalised Berlekamp-Massey algorithm
(2002-08-01)
Cheng, MH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The Berlekamp-Massey algorithm is revisited and proven again by using the matrix representation. This approach makes the derivation and proof of the algorithm straightforward, simple and easily understood. It further enables the presentation of a generalised Berlekamp-Massey algorithm, including the conventional algorithm and the inversion-free algorithm as two special cases.
Joint design of interpolation filters and decision feedback equalizers
(2005-06-01)
Cheng, MH
;
Kao, TS
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents an algorithm to design jointly interpolation filters and decision feedback equalizers in the sense of minimum mean-square error such that the joint capacity which is neglected in conventional design is explored to improve the receiver performance. The algorithm comprises an iteration of two alternating simple quadratic minimizing operations and ensures convergence. A simulation example for the raised-cosine channel demonstrates that via this approach an improvement over the conventional design can be achieved.
Joint design of interpolation filters and frequency equalizers in DMT systems for XDSL applications
(2005)
Cheng, MH
;
Lu, PH
;
Wu, JF
;
電控工程研究所
;
Institute of Electrical and Control Engineering
We formulate the joint design of interpolation filter and frequency equalizer in DMT systems as the problem for minimization of the mean square error between the input data symbol and its output estimate. Then an iterative algorithm is proposed for solution. Each iteration requires only solving two quadratic minimizations; the algorithm also ensures convergence. Simulations for VDSL applications demonstrate that an increment in transmission rate can be achieved compared with the conventional design of the interpolation filter and frequency equalizer separately.
Low temperature radio-frequency-sputtered (Ba, Sr)TiO3 films on Pt/TiN/Ti/Si substrates with various oxygen/argon mixing ratios
(2003-02-01)
Shye, DC
;
Chiou, BS
;
Lai, MJ
;
Hwang, CC
;
Jiang, CC
(Ba, Sr) TiO3 (BST) films were fabricated on Pt/TiN/Ti/Si substrates by low temperature radio frequency magnetron cosputtering at 300degreesC. Material and electrical properties of BST films sputtered at low temperatures are significantly affected by the O-2/(Ar + O-2) mixing ratio (OMR). Plasma emission spectra indicate that the deposition rate declines at a higher OMR due to oxide formation on the target surface. The dielectric constant of the BST films can reach a maximum of 364 at 5% OMR. The ten-year lifetime of the time-dependent dielectric breakdown implies that the reliability of the capacitor can be enhanced at a higher OMR due to compensation of oxygen vacancies and smaller grain sizes. Current-voltage analysis indicates that the leakage current of the Pt/BST/Pt capacitor is limited by Schottky emission (SE)/Poole-Frenkel emission (PF) at a lower/higher applied field. The applied field boundary between SE and PF shifts toward higher field as OMR increases. Moreover, an energy band model was proposed and this leakage mechanism was discussed. (C) 2003 The Electrochemical Society.
Low-power low-voltage reference using peaking current mirror circuit
(2005-05-12)
Cheng, MH
;
Wu, ZW
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A low-power low-voltage bandgap reference using the peaking current mirror circuit with MOSFETs operated in the subthreshold region is presented. A demonstrative chip was fabricated in 0.35 mu m CMOS technology, achieving the minimum supply voltage 1.4 V, the reference voltage around 580 mV, the temperature coefficient 62 ppm/degrees C, the supplied current 2.3 mu A, and the power supply noise rejection ratio of -84 dB at 1 kHz.
Maximum-likelihood estimation of frequency and time offsets in OFDM systems with multiple sets of identical data
(2006-07-01)
Cheng, MH
;
Chou, CC
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper generalizes the existing algorithm for the maximum-likelihood (NIL) estimation of frequency and time offsets in orthogonal frequency-division multiplexing (OFDM) systems using from two sets to multiple sets of identical data. The algorithm is derived by the application of the matrix inversion lemma; the Cramer-Rao bound for estimation of the frequency offset is also obtained. For reducing realization complexity, a simplified algorithm is developed. Simulations using the ten sets of identical data in the preamble of IEEE 802.11a for estimation of frequency and time offsets have been performed to verify the effectiveness of the proposed algorithms.
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.
Shear-wave velocities from multi-station analysis of surface wave
(2003)
Lin, CP
;
Chang, TS
;
Cheng, MH
;
交大名義發表
;
National Chiao Tung University
Site characterization using surface waves is becoming more and more popular because of its advantages over intrusive methods. Multi-station methods are presented to recommend a better procedure to construct the experimental dispersion curve including data acquisition, test configuration, and data analysis. A method based on the linear regression of phase angles measured at multiple stations are proposed for determining data quality and filtering criteria. This method becomes a powerful tool for on site quality control in real time. Multi-channel recording permits single survey of a broad depth range, high levels of redundancy with a single field configuration, and the ability to adjust the offset, effectively reducing near field effect, far field effect, and other coherent noise introduced during recording. The effects of multiple modes and survey line parameters, such as source offset, receiver spacing, and total length of the survey line, are investigated. The parametric study results in a general guideline for the field data acquisition. A case study demonstrates how to easily deploy commonplace seismic refraction equipment to simultaneously record data for P-wave tomographic interpretation and multi-station analysis of surface wave.