Browsing by Author "Yang, CH"

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Analyzing type II censored data obtained from repetitious experiments
(2006-01-01)
Tong, LI
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Yang, CH
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Experimental design and Taguchi's parameter design are widely employed by industry to optimize the process/product. However, censored data are often observed in product lifetime testing during the experiments. After implementing a repetitious experiment with type II censored data, the censored data are usually estimated by establishing a complex statistical model. However, using the incomplete data to fit a model may not accurately estimates the censored data. Moreover, the model fitting process is complicated for a practitioner who has only limited statistical training. This study proposes a less complex approach to analyze censored data, using the least square estimation method and Torres's analysis of unreplicated factorials with possible abnormalities. This study also presents an effective method to analyze the censored data from Taguchi's parameter design using least square estimation method. Finally, examples are given to illustrate the effectiveness of the proposed methods.
Back-gate forward bias method for low-voltage CMOS digital circuits
(1996-06-01)
Chen, MJ
;
Ho, JS
;
Huang, TH
;
Yang, CH
;
Jou, YN
The back-gate forward bias method suitable for present standard hulk CMOS processes has been promoted for low-voltage digital circuit application, A CMOS inverter employing the method has experimentally exhibited the ability of electrically adjusting the transition region of the de voltage transfer characteristics. Transient measurement has further shown that the inverter with a back-gate forward bias of 0.4 V can operate at low supply voltages down to 0.6 V without significant loss in switching speed, Guidelines for ensuring proper implementation of tile method in a bulk CMOS process has been set up against latch-up, parasitic bipolar, impact ionization, and stand-by current, Following these guidelines, a cost-effective low-power, low-voltage, high-density mixed-mode CMOS analog/digital integrated circuits chip with both reasonable speed and improved precision has been projected for the first time.
Cascaded trellis-based rate-distortion control algorithm for MPEG-4 advanced audio coding
(2006-05-01)
Yang, CH
;
Hang, HM
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a few low-complexity and high-performance rate-distortion control algorithms for MPEG-4 Advanced Audio Coding (AAC) are proposed. One key element in producing good quality compressed audio particularly at medium and low rates is a high performance rate-distortion controller in the audio encoder. Although the trellis-based rate-distortion control algorithms previously proposed can achieve a praiseworthy performance, their computational complexity is extremely high. Therefore, for practical applications, it is very desirable to achieve a similar performance at a much lower complexity. Two types of techniques are proposed in this paper to reduce the computational burden of the trellis-based algorithms. One is splitting a very heavy calculation stage into two sequential steps with much less computation. The other is reducing the candidates in the trellis for parameter search. Together, when applicable, our approach achieves a similar coding performance (audio quality) but requires less than 1/1000 complexity in computation.
Cation substitution effects on structural, electronic and optical properties of nonlinear optical AgGa(SxSe1-x)(2) crystals
(2003-09-10)
Tang, LC
;
Lee, MH
;
Yang, CH
;
Huang, JY
;
Chang, CS
The structural, electronic and optical properties of tetragonal nonlinear optical (NLO) crystals, AgGa(SxSe1-x)(2) (x = 0.0, 0.25, 0.5, 0.75, and 1.0), were investigated theoretically and experimentally. The results obtained indicated that the electronic bandgaps, optical properties and bulk moduli of these compounds were linearly dependent on the substitution concentration of cations. From partial density of state analysis, it was found that the electronic states near the band edges of AgGa(SxSe1-x)(2) were a simple proportional mixture of the atomic orbitals of sulfur and selenium. A cell-volume effect was proposed as the major cause of the linear dependence of material properties on the substitution concentration. It was calculated that the second-order NLO susceptibilities were scaled with the cubic power of bandgap, although a minor deviation existed. This deviation arose from the optical transition moment products.
Constructing control process for wafer defects using data mining technique
(2004)
Tong, L
;
Lee, H
;
Huang, CF
;
Lin, CK
;
Yang, CH
The wafer defects influence the yield of a wafer. The integrated circuits (IC) manufacturers usually use a Poisson distribution based c-chart to monitor the lot-to-lot wafer defects. As the wafer size increases, defects on wafer tend to cluster. When the c-chart is used, the clustered defects frequently cause erroneous results. The main objective of this study is to develop a hierarchical adaptive control process to monitor the clustered defects effectively and detect the wafer-to-wafer variation and lot-to-lot variation simultaneously using data mining technique.
Effects of postdeposition annealing on the characteristics of HfOxNy dielectrics on germanium and silicon substrates
(2006)
Cheng, CC
;
Chien, CH
;
Chen, CW
;
Hsu, SL
;
Yang, CH
We have systematically investigated the impact that postdeposition annealing (PDA) has on the physical and electrical properties of HfOxNy thin films sputtered on Ge and Si substrates. These two substrates display contrasting metal-oxide-semiconductor characteristics that we attribute to the different compositions of their interface layers (ILs). We observed an increased GeO2 incorporation into the HfOxNy dielectric and severe volatilization of the IL on Ge after higher PDA processing. These undesired phenomena in the HfOxNy/Ge gate stacks may be responsible for their different electrical properties with respect to those of the HfOxNy/Si gate stacks, i.e., a further scaling of the capacitance-equivalent thickness, a significant presence of fixed positive charges and electron-trapping sites, and a degradation of dielectric reliability. In addition, the anomalous low-frequency-like behavior of the high-frequency capacitance-voltage curves in inversion for the Ge capacitors was predicted from theoretical calculations. (c) 2006 The Electrochemical Society.
Efficient bit assignmet strategy for perceptual audio coding
(2003)
Yang, CH
;
Hang, HM
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
For the purpose of efficient audio coding at low rates, a new bit allocation strategy is proposed in this paper. The basic idea behind this approach is "Give bits to the band with the maximum NMR-Gain/bit" or "Retrieve bits from the band with the maximum bits/NMR-Loss". The notion of "bit-use efficiency" is suggested and it can be employed to construct a bit assignment algorithm operated at band-level as compared to the traditional frame-level bit assignment methods. Based on this strategy a new bit assignment scheme, called Max-BNLR, is designed for the MPEG-4 AAC. Simulation results show that the performance of the Max-BNLR scheme is significantly better than that of the MPEG-4 AAC Verification Model (VM) and is close to that of TB-ANMR [3], which is the (nearly) optimal solution. Moreover, the Max-BNLR scheme has the advantages of low computational complexity comparing to TB-ANMR.
Fast perceptual convolution for room reverberation
(2003)
Lee, WC
;
Liu, CM
;
Yang, CH
;
Guo, JI
;
資訊工程學系
The FIR-based reverberators, which convolve the input sequence with an impulse response modelling the concert hall, have better quality compared to the IIR-based approach. However, the high computational complexity of the FIR-based reverberators limits the applicability to most cost-oriented system. This paper introduces a method that uses perceptual criterion to reduce the complexity of convolution methods for reverberation. Also, an objective measurement criterion is introduced to check the perceptual difference from the reduction. The result has shown that the length of impulse response can be cut off by 60% without affecting the perceptual reverberation quality. The method is well integrated into the existing FFT-based approach is have around 30% speed-up.
Glass-chip-based sample preparation and on-chip trypic digestion for matrix-assisted laser desorption/ionization mass spectrometric analysis using a sol-gel/2,5-dihydroxybenzoic acid hybrid matrix
(2004)
Lin, YS
;
Yang, CH
;
Chen, YC
;
應用化學系
;
Department of Applied Chemistry
A glass-chip-based sample preparation method for matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) analysis of tryptic digests of proteins and intact cells is described. A MALDI matrix, 2,5-dihydroxybenzoic acid (2,5-DHB), was hybridized with sol-gels to generate a sol-gel-derived material. Taking advantage of the characteristics of sol-gels, the sol-gel-derived material readily adhered to the surface of a glass chip through covalent bonding. Only one step of sample preparation, deposition of the sample solution on the glass chip, was required before MALDI-MS analysis. Because 2,5-DHB was homogeneously dispersed on the sol-gel network structure, good spot-to-spot reproducibility was obtained in MALDI analysis using this approach and the analyte signals were uniform throughout the chip. The modified glass chips were robust and effective for at least 1 week. This glass-chip-based matrix preparation method provides a straightforward approach to developing techniques for analyzing the on-chip enzymatic digestion of proteins and intact cells of microorganisms. Cytochrome C and Escherichia coli were used as analytes to demonstrate the feasibility of this approach. The products of the on-chip enzymatic digests were identified through protein database searches. Copyright (C) 2004 John Wiley Sons, Ltd.
Heteroleptic cyclometalated iridium(III) complexes displaying blue phosphorescence in solution and solid state at room temperature
(2005-10-31)
Yang, CH
;
Li, SW
;
Chi, Y
;
Cheng, YM
;
Yeh, YS
A series of heteroleptic Ir(III) metal complexes 1-3 bearing two N-phenyl-substituted pyrazoles and one 2-pyridyl pyrazole (or triazole) ligands were synthesized and characterized to attain highly efficient, room-temperature blue phosphorescence. The N-phenylpyrazole ligands, dfpzH = 1-(2,4-difluorophenyl)pyrazole, fpzH = 1-(4-fluorophenyl)-pyrazole, dfmpzH = 1-(2,4-difluorophenyl)-3,5-dimethylpyrazole, and fmpzH = 1-(4-fluorophenyl)-3,5-dimethylpyrazole, show a similar reaction pattern with respect to the typical cyclometalated (C boolean AND N) chelate, which utilizes its orthosubstituted phenyl segment to link with the central Ir(III) atom, while the second 2-pyridylpyrazole (or triazole) ligand, namely, fppzH = 3-(trifluoromethyl)-5-(2-pyridyl)pyrazole, fptzH = 3-(trifluoromethyl)-5-(2-pyridyl)triazole, and hptzH = 3-(heptafluoropropyl)-5-(2-pyridyl)triazole, undergoes typical anionic (N boolean AND N) chelation to complete the octahedral framework. X-ray structural analyses on complexes [(dfPZ)(2)Ir(fppz)] (1a) and [(fMPZ)(2)Ir(hptz)] (3d) were established to confirm their molecular structures. Increases of the pi pi* energy gaps of the Ir(III) metal complexes were systematically achieved with two tuning strategies. One involves the substitution for one or two fluorine atoms at the N-phenyl segment or the introduction of two electron-releasing methyl substituents at the pyrazole segment of the H(CAN) ligands. Alternatively, we have applied the more electron-accepting triazolate in place of the pyrazolate segment for the third (N boolean AND N)H ligand, Our results, on the basis of steady-state, relaxation dynamics, and theoretical approaches, lead to a conclusion that, for complexes 1-3, the weakening of iridium metal-ligand bonding strength in the T-1 state plays a crucial role for the fast radiationless deactivation. For the case of [(fMPZ)(2)Ir(hptz)] (3d), a thermal deactivation barrier of 4.8 kcal/mol was further deduced via temperature-dependent studies. The results provide a theoretical basis for future design and synthesis of the corresponding analogues suited to blue phosphorescent emitters.
Non-linear dynamics and chaos control of a physical pendulum with vibrating and rotating support
(2001-04-26)
Ge, ZM
;
Yang, CH
;
Chen, HH
;
Lee, SC
;
機械工程學系
The dynamic behavior of a physical pendulum system of which the support is subjected to both rotation and vertical vibration are studied in this paper. Both analytical and computational results are employed to obtain the characteristics of the system. By using Lyapunov's direct method the conditions of stability of the relative equilibrium position can be determined. Melnikov's method is applied to identify the existence of chaotic motion. The incremental harmonic balance method is used to find the stable and unstable periodic solutions For the strong non-linear system. By applying various numerical results such as phase portrait, Pioncare map. time history and power spectrum analysis, a variety of the periodic solutions and the phenomena of the chaotic motion can be presented. The effects of the changes of parameters in the system could be found in the bifurcation and parametric diagrams. Further, chaotic motion can be verified by using Lyapunov exponent and Lyapunov dimension. The global analysis of basin boundary and fractal structure are observed by the modified interpolated cell mapping method. Besides, non-feedback control, delayed feedback control, adaptive control, and variable structure control are used to control the chaos effectively. (C) 2001 Academic Press.
Protein metal binding residue prediction based on neural networks
(2005-02-01)
Lin, CT
;
Lin, KL
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Yang, CH
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Chung, IF
;
Huang, CD
Over one-third of protein structures contain metal ions, which are the necessary elements in life systems. Traditionally, structural biologists were used to investigate properties of metalloproteins (proteins which bind with metal ions) by physical means and interpreting the function formation and reaction mechanism of enzyme by their structures and observations from experiments in vitro. Most of proteins have primary structures (amino acid sequence information) only; however, the 3-dimension structures are not always available. In this paper, a direct analysis method is proposed to predict the protein metal-binding amino acid residues from its sequence information only by neural networks with sliding window-based feature extraction and biological feature encoding techniques. In four major bulk elements (Calcium, Potassium, Magnesium, and Sodium), the metal-binding residues are identified by the proposed method with higher than 90% sensitivity and very good accuracy under 5-fold cross validation. With such promising results, it can be extended and used as a powerful methodology for metal-binding characterization from rapidly increasing protein sequences in the future.
Protein metal binding residue prediction based on neural networks
(2004)
Lin, CT
;
Lin, KL
;
Yang, CH
;
Chung, IF
;
Huang, CD
It is known that over one-third of protein structures contain metal ions, and they are the necessary elements in life system. Traditionally, structural biologists used to investigate properties of metalloproteins (proteins which bind with metal ions) by physical means and interpret the function formation and reaction mechanism of enzyme by their structures and observation from experiments in vitro. Most of proteins have primary structures (amino acid sequence information) only; however, the 3-dimension structures are not always available. In this paper, a direct analysis method is proposed to predict protein metalbinding amino acid residues only from its sequence information by neural network with sliding window-based feature extraction and biological feature encoding techniques and it can successfully detect 15 binding elements in protein, and 6 binding elements in enzyme.
Rectangular meshes construction of the human urethra using 3-D GVF snakes
(2004)
Ching, YT
;
Lin, CY
;
Tan, KC
;
Lau, KL
;
Yang, CH
Accurate 3-D rectangular meshes construction of pipes is important and valuable for Engineering and Medicine to analyze the fluid mechanics. Hypertrophied prostate is suffered common by aged patient. Medicine trusts that the pathogenic reason can be interpreted using the statistics of analysis of fluid mechanics. We use serials of methods to construct the 3-D rectangular meshes of a patient urethra CT volumetric data given from medicine, and for mechanic engineering to gather statistics.
The dynamical correlation in spacer-mediated electron transfer couplings
(2006-06-28)
Yang, CH
;
Hsu, CP
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應用化學系分子科學碩博班
;
Institute of Molecular science
The dynamical correlation effect in electron transfer (ET) coupling was studied in this work, for cases where electrons tunnel through a many-electron environment. The ET couplings for three different bridge-mediated model systems were calculated: (I) trans-alkyl chains [H2C-(CH2)(n)-CH2, n=2-10], (II) two isomers of trans-1,4-dimethylenecyclohexane, and (III) two ethylenes spaced by a saturated ethane molecule. The couplings were calculated as half energy gaps of the two lowest adiabatic states. The dynamical correlation was included with spin-flip (SF) and ionization potential or electron affinity coupled-cluster singles and doubles (SF-CCSD and IP/EA-CCSD) and a Delta CCSD scheme. The direct coupling (DC) scheme is also used as a way to obtain a solution with nondynamical correlation, since DC uses approximated eigenstates that are symmetry-restoring linear combinations of two symmetry-broken unrestricted Hartree-Fock configurations. For all cases tested except for one, results from the DC scheme closely follow the CCSD data, indicating that the dual-configuration solutions can be a good approximation of wave functions with nondynamical correlation included, but there exist exceptions. Comparing the DC results with SF-CCSD and IP or EA-CCSD data, we concluded that the dynamical correlation effect is small for most of the cases we tested. (c) American Institute of Physics.