Browsing by Author "Chen, WY"

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A Fuzzy Markov approach for assessing groundwater pollution potential for landfill siting
(2002-04-01)
Chen, WY
;
Kao, JJ
;
環境工程研究所
;
Institute of Environmental Engineering
This Study presents a Fuzzy Markov groundwater Pollution potential assessment approach to facilitate landfill siting analysis. Landfill siting is constrained by various regulations and is complicated by the uncertainty of groundwater related factors. The conventional static rating method cannot properly depict the potential impact of Pollution on a groundwater table because the groundwater table level fluctuates. A Markov chain model is a dynamic model that can be viewed as a hybrid of probability and matrix models. The probability matrix of the Markov chain model is determined based on the groundwater table elevation time series. The probability reflects the likelihood of the groundwater table changing between levels. A fuzzy set method is applied to estimate the degree of pollution potential, and a case study demonstrates the applicability of the proposed approach. The short- and long-term pollution potential information provided by the proposed approach is expected to enhance landfill siting decisions.
A modified HICUM model for GaInP/GaAs HBT devices
(2006-04-01)
Tseng, SC
;
Meng, CC
;
Chen, WY
;
Su, JY
;
電信工程研究所
A compact physics-based transit-time model is established for the GaInP/GaAs HBT device. The VBIC model fails to describe the transit-time frequency versus bias (I-C, V-CE), especially at low- and medium-current regimes. Starting with the HICUM model, we introduce a new time constant to describe the transit-time frequency versus bias (I-C, V-CE) more precisely. This model has obvious advantages over the VBIC model for showing the relation oj'f, versus bias (I-C, V-CE) in the low and medium current regimes for GaInP/GaAs HBT devices. (c) 2006 Wiley Periodicals, Inc.
A novel vision system for CRT panel auto-inspection
(2005)
Perng, DB
;
Chou, CC
;
Chen, WY
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
The defects of a 3-D translucent hull CRT panel may include scratches, blemishes, cracks, bubbles, or collapsed portions. Defects may occur on the inside surface, outside surface, or interior of the glass. We designed and developed three sets of vision systems which can automatically inspect defects in CRT panels. The first system inspects the front-surface and two turn-segments, the second system inspects the other two turn-segments, while the third system inspects the side-wall defects. Two different kinds of lighting environments were developed to highlight the CRT panels and to simplify the image-capturing process. Meanwhile, a set of image processing methods were devised which can reliably detect the defects within the expected processing time. Experimental results demonstrate that the developed vision systems can be used to inspect CRT panels in the production line.
A speech recognition method based on the sequential multi-layer perceptrons
(1996-06-01)
Chen, WY
;
Chen, SH
;
Lin, CJ
;
交大名義發表
;
National Chiao Tung University
A novel multi-layer perceptrons (MLP)-based speech recognition method is proposed in this study. In this method, the dynamic time warping capability of hidden Markov models (HMM) is directly combined with the discriminant based learning of MLP for the sake of employing a sequence of MLPs (SMLP) as a word recognizer. Each MLP is regarded as a state recognizer to distinguish an acoustic event. Next, the word recognizer is formed by serially cascading all state recognizers. Advantages of both HMM and MLP methods are attained in this system through training the SMLP with an algorithm which combines a dynamic programming (DP) procedure with a generalized probabilistic descent (GPD) algorithm. Additionally, two sub-syllable SMLP-based schemes are studied through application of this method toward the recognition of isolated Mandarin digits. Simulation results confirm that the performance of the methods is comparable to a well modeled continuous Gaussian mixture density HMM trained with the minimum error criterion. Not only does the SMLP require less trainable parameters than the HMM system, but the former is more convenient for analysing internal features. With the aid of internal feature selection, discarding the least useful parameters of SMLP without affecting its performance is relatively easy. Copyright (C) 1996 Elsevier Science Ltd
Carbon nanotubes as affinity probes for peptides and proteins in MALDI MS analysis
(2004-11-01)
Chen, WY
;
Wang, LS
;
Chiu, HT
;
Chen, YC
;
Lee, CY
Recently, carbon nanotubes (CNTs) have been reported to be an effective MALDI matrix for small molecules Anal. Chem 2003, 75, 6191). In a somewhat related study, we have employed CNTs produced by using NaH-treated anodic aluminum oxide (Na@AAO) as a reactive template as the assisting matrix for MALDI analysis upon the addition of high concentrations of citrate buffer. Our results indicate that the mass range can be extended to ca. 12,000 Da and that alkali metal adducts of analytes are effectively reduced. Furthermore, we have employed citric acid-treated CNTs as affinity probes to selectively concentrate traces of analytes from aqueous solutions. High concentrations of salts and surfactants in the sample solutions are also tolerated. This approach is very suitable for the MALDI analysis of small proteins, peptides, and protein enzymatic digest products. (J Am Soc Mass Spectrom 2004, 15, 1629-1635) (C) 2004 American Society for Mass Spectrometry.
Continuous mandarin speech recognition using hierarchical recurrent neural networks
(1996)
Liao, YF
;
Chen, WY
;
Chen, SH
;
交大名義發表
;
National Chiao Tung University
Design on power-rail ESD clamp circuit for 3.3-V I/O interface by using only 1-V/2.5-V low-voltage devices in a 130-nm CMOS process
(2005)
Ker, MD
;
Chen, WY
;
Hsu, KC
;
電機學院
;
College of Electrical and Computer Engineering
A new power-rail ESD clamp circuit in a 130-nm 1-V/2.5-V CMOS process for application in 3.3-V mixed-voltage I/O interface is proposed. The devices used in this power-rail ESD clamp circuit are all 1-V or 2.5-V low-voltage NMOS/PMOS devices, which are specially designed without suffering the gate-oxide reliability issue under 3.3-V 1/0 interface applications. A special ESD detection circuit realized with the low-voltage devices is designed to improve ESD robustness of the stacked NMOS by substrate-triggered technique. The experimental results verified in a 130-nm CMOS process have proven the excellent effectiveness of this new proposed power-rail ESD clamp circuit.
Design to avoid the over-gate-driven effect on ESD protection circuits in deep-submicron CMOS processes
(2004)
Ker, MD
;
Chen, WY
;
電機學院
;
College of Electrical and Computer Engineering
Although the gate-driven (or gate-coupled) technique was reported to improve ESD robustness of NMOS devices, the over-gate-driven effect has been found to degrade ESD level. This effect makes the gate-driven technique hard to be well optimized in deep-submicron CMOS ICs. In this work, a new design is proposed to overcome such over-gate-driven effect by circuit design and to achieve the maximum ESD capability of devices. The experimental results have shown significant improvement on the machine-model (MM) ESD robustness of ESD protection circuit by this new proposed design. This new design is portable (process-migration) for applications in different CMOS processes without modifying the process step or mask layer.
Enhancement of light-output of GaN-based light-emitting diodes by bias-assisted photoelectrochemical oxidation of p-GaN in H2O
(2005)
Lai, FI
;
Chen, WY
;
Kao, CC
;
Lin, CF
;
Kuo, HC
An enhancement of GaN-based LEDs light output using photoelectrochemical (PEC) oxidation method via H2O on the p-GaN surface was demonstrated. The output light was improved 37% after 45min PEC oxidation.
Influence of PMMA-chain-end tethered polyhedral oligomeric silsesquioxanes on the miscibility and specific interaction with phenolic blends
(2006-01-10)
Huang, CF
;
Kuo, SW
;
Lin, FJ
;
Huang, WJ
;
Wang, CF
Two different molecular weights of poly(methyl methacrylate) (PMMA) and PMMA containing polyhedral oligomeric silsesquioxane (PMMA-POSS) homopolymers have been prepared via the atom transfer radical polymerization (ATRP) technique. The miscibility and specific interaction behaviors of PMMA-POSS and PMMA with phenolic resin were investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). FTIR results reveal that at least three competing equilibriums are present in the phenolic/PMMA-POSS blend: self-association of phenolic (hydroxyl-hydroxyl), hydroxyl-siloxane interassociation between phenolic and POSS, and hydroxyl-carbonyl interassociation between phenolic and PMMA. Among these blends, single and higher T(g)s of these phenolic/PMMA-POSS blends were observed than the corresponding phenolic/PMMA blends at same composition, revealing that a stronger interassociation interaction of hydroxyl-siloxane than the hydroxyl-carbonyl interaction. Furthermore, we also found the screening effect in phenolic/LPMMA-POSS blends that tends to significantly decrease the hydrogen bond formation of the hydroxyl-carbonyl interassociation.
Network expert geographic information system for landfill siting
(1996-10-01)
Kao, JJ
;
Chen, WY
;
Lin, HY
;
Guo, SJ
;
環境工程研究所
A prototypical network expert geographic information system (GIS) is developed to facilitate municipal solid waste landfill siting. A forward chaining knowledge base consisting of related siting rules extracted from various literature is used to establish an expert system. Siting analysis is performed by a GIS and evaluated by rules triggered from the expert system. The expert system and GIS are integrated into an expert GIS to combine the advantages of both systems. Also, a multimedia network interface is designed for local or remote access to the system from anywhere on the Internet. With the interface, a general user does not require previous knowledge of the expert system and GIS to use the system. This networking capability not only significantly reduces the cost of distributing tools to each user, but also avoids the difficulty that each user may encounter in installing and managing tools on the computer. Finally, a case study is provided to demonstrate the effectiveness of the developed system in facilitating landfill-siting analysis. The system can be directly accessed via Internet from the home page http://ev004.ev.nctu.edu.tw/ENGLISH/wsite/index.html.
Network expert geographic information system for landfill siting
(1996-10-01)
Kao, JJ
;
Chen, WY
;
Lin, HY
;
Guo, SJ
;
交大名義發表
A prototypical network expert geographic information system (GIS) is developed to facilitate municipal solid waste landfill siting. A forward chaining knowledge base consisting of related siting rules extracted from various literature is used to establish an expert system. Siting analysis is performed by a GIS and evaluated by rules triggered from the expert system. The expert system and GIS are integrated into an expert GIS to combine the advantages of both systems. Also, a multimedia network interface is designed for local or remote access to the system from anywhere on the Internet. With the interface, a general user does not require previous knowledge of the expert system and GIS to use the system. This networking capability not only significantly reduces the cost of distributing tools to each user, but also avoids the difficulty that each user may encounter in installing and managing tools on the computer. Finally, a case study is provided to demonstrate the effectiveness of the developed system in facilitating landfill-siting analysis. The system can be directly accessed via Internet from the home page http://ev004.ev.nctu.edu.tw/ENGLISH/wsite/index.html.
Network geographic information system for landfill siting
(1997-06-01)
Kao, JJ
;
Lin, HY
;
Chen, WY
;
交大名義發表
;
環境工程研究所
A prototype network geographic information system (GIS) was developed to: (i) improve the effectiveness of a complex municipal solid waste landfill siting procedure; (ii) make siting-related information available to the general public; (iii) assist local environmental protection agencies in maintaining a GIS; and (iv) facilitate the central environmental protection agency in managing, instructing and evaluating the progress of a local siting. Siting analysis is performed with computerized mapping analysis to save time and effort of data processing. A multimedia network interface is provided for 24-hour local or remote access to the system from anywhere on the Internet. This networking capability allows a user without tools to utilize the system and to avoid the cost of system installation and training appropriate personnel to manage the system. Moreover, a case study for Miaoli is described. Environmental, social, economic and engineering feasibility issues are evaluated for the suitability of a candidate landfill site. (C) 1997 ISWA.
Network geographic information system for landfill siting
(1997-06-01)
Kao, JJ
;
Lin, HY
;
Chen, WY
;
環境工程研究所
;
Institute of Environmental Engineering
A prototype network geographic information system (GIS) was developed to: (i) improve the effectiveness of a complex municipal solid waste landfill siting procedure; (ii) make siting-related information available to the general public; (iii) assist local environmental protection agencies in maintaining a GIS; and (iv) facilitate the central environmental protection agency in managing, instructing and evaluating the progress of a local siting. Siting analysis is performed with computerized mapping analysis to save time and effort of data processing. A multimedia network interface is provided for 24-hour local or remote access to the system from anywhere on the Internet. This networking capability allows a user without tools to utilize the system and to avoid the cost of system installation and training appropriate personnel to manage the system. Moreover, a case study for Miaoli is described. Environmental, social, economic and engineering feasibility issues are evaluated for the suitability of a candidate landfill site. (C) 1997 ISWA.
Reducing the alkali cation adductions of oligonucleotides using sol-gel-assisted laser desorptionionization mass spectrometry
(2003-08-15)
Chen, WY
;
Chen, YC
;
應用化學系
;
Department of Applied Chemistry
The alkali cation adductions of oligonucleotides dramatically degrade MALDI mass spectra and even affect the detection limit. Desalting is generally involved in MALDI sample preparation. This work demonstrates the feasibility of using 3,4-diaminobenzoic acid (DABA) and 3,5-DABA as the MALDI matrix for oligonucleotide analysis. Furthermore, sodium ion adducts of oligonucleotides were simultaneously reduced in the mass spectra when DABA was used as the MALDI matrix and sol-gel material was used as the sample support. However, depositing the sample on the sample support was very difficult, and the lack of homogeneity of analytes/matrix distribution on the sample support also led the analyte signals to be revealed only in "sweet spots". Alternatively, DABA was doped into sol-gel materials to generate homogeneous DABA/sol-gel hybrid film. The DABA/sol-gel hybrid film was used as the sample substrate to assist the desorption/ionization of analytes. The analyte signals were evenly found on the sample substrate. The sodium ion adductions of oligonucleotides were also effectively suppressed. The sample preparation used in this approach resembles that used in the authors' previous study, involving sol-gel-assisted laser desorption/ionization (SGALDI) mass spectrometry (Lin, Y.-S.; Chen, Y.-C. Anal. Chem. 2002, 74, 5793-5798.) The SGALDI approach was demonstrated to be effective in assisting the desorption/ionization of peptides and small proteins. Herein, the SGALDI material, DABA/sol-gel hybrid material, was successfully applied to oligonucleotide analysis, and good-quality mass spectra were obtained without extra desalting. Additionally, the presence of 0.1% SDS in the oligonucleotide sample solution was tolerated without degrading the mass spectra. The largest detectable molecular size for oligonucleotides was 72 mer. The detection limit for 24 mer of oligonucleotide was 20 fmol.
Simultaneous preparation of PI/POSS semi-IPN nanocomposites
(2006-03-24)
Chen, WY
;
Ko, SH
;
Hsieh, TH
;
Chang, FC
;
Wang, YZ
This investigation presents a simultaneous and convenient approach to produce a high-performance polyimide with a low dielectric constant by introducing the octa-acrylated polyhedral oligomeric silsesquioxane (methacrylated-POSS) into a polyimide matrix to form polyimide semi-interpenetrating polymer network (semi-IPN) nanocomposites. The differential scanning calorimetry (DSC) and Fourier-transform infrared (FT-IR) results indicate that the self-curing of methacrylated-POSS and the imidization of polyamic acid (PAA) occurs simultaneously. The morphology of a semi-IPN structure of polyimide[POSS-PI/POSS nanocomposites with POSS nanoparticles embedded inside the matrix is elucidated. The POSS particles are uniform and are aggregated to a size of approximately 50-60 nm inside the polyimide matrix. The interconnected POSS particles are observed at high POSS content. The structure is highly crosslinked, so the PI/POSS nanocomposites have an enhanced glass transition temperature. The high porosity of the PI/POSS nanocomposites markedly reduces the dielectric constant of PI because of the nanometer-scale porous structure of POSS.
Study on curing kinetics and curing mechanism of epoxy resin based on diglycidyl ether of bisphenol A and melamine phosphate
(2004-04-15)
Chen, WY
;
Wang, YZ
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
The curing kinetics of the diglycidyl ether of bisphenol A/melamine phosphate (DGEBA/MP) was analyzed by the DSC technique. The Kissinger and Flynn-Wall-Ozawa methods were applied to determine the dynamic kinetics of the DGEBA/MP system. The activation energies obtained by these two methods were 83.9 and 85.6 kJ/mol, respectively. An autocatalytic equation was applied to determine the isothermal curing kinetics of the DGEBA/MP system. The DGEBA/MP system exhibits autocatalytic behavior in the isothermal curing procedure, whose kinetics fits well with the autocatalytic mechanism. The obtained isothermal curing activation energy of the DGEBA/MP system was 110.0 kJ/mol. The curing mechanism of DGEBA with melamine phosphate was investigated using FTIR, C-13 solid-state NMR, and P-31 solid-state NMR. It involved an epoxide-amine reaction, etherification of phosphoric acid and epoxy, dehydration, and thermal oxidation of the hydroxyl group of the DGEBA/MP system. (C) 2004 Wiley Periodicals, Inc.
Synthesis of a novel benzoxazine monomer-intercalated montmorillonite and the curing kinetics of polybenzoxazine/clay hybrid nanocomposites
(2006-01-15)
Yei, DR
;
Fu, HK
;
Chen, WY
;
Chang, FC
;
應用化學系
Polybenzoxazine (PBZ), which has a structure similar to that of phenolic resin, is formed through the thermal self-curing of benzoxazine, that is through a heterocyclic ring opening reaction that requires no catalyst and releases no condensation byproducts. We have used the solvent blending method to prepare PBZ/clay nanocomposites possessing various clay contents. We synthesized a monofunctional benzoxazine monomer (MBM) and then treated the clay with this intercalation agent. The results of X-ray diffraction (XRD) analysis indicated that MBM intercalated into the galleries of the clay; the nanocomposite possessed an exfoliated structure at 3% clay content. To better understand the curing kinetics of the PBZ/clay nanocomposites, we performed dynamic and isothermal differential scanning calorimetry (DSC) measurements. We describe the thermodynamics of the curing process, using all three of the Kissinger, Ozawa, and Kamal models. The Kissinger and Ozawa methods gave fairly close results for the calculated activation energies, which decreased upon increasing the clay content. The Kamal method, based on an autocatalytic model, suggested a total reaction order of between 2.4 and 2.8. The glass transition temperature (T,) decreased upon increasing the clay content. Thermogravimetric analysis (TGA) indicated that the nanocomposites have higher decomposition temperatures than does the pristine PBZ; this finding suggests an enhancement in their thermal stability. (c) 2005 Wiley Periodicals, Inc.
Thermal and dielectric properties and curing kinetics of nanomaterials formed from poss-epoxy and meta-phenylenediamine
(2004-09-16)
Chen, WY
;
Wang, YZ
;
Kuo, SW
;
Huang, CF
;
Tung, PH
A nanoporous polyhedral oligomeric silisesquioxane (POSS) containing eight epoxy functional groups [octakis(dimethylsiloxypropylglycidyl ether)silsesquioxane, OG] reacts with meta-phenylenediamine (mPDA) to form epoxy resin network with nanostructures. The glass transition temperature (T-g) of the cured OG/mPDA product is significantly higher than that of the diglycidyl ether of bisphenol A (DGEBA) cured with mPDA (DGEBA/mPDA) material due to the presence of the POSS cages that is able to effectively hinder the motion of the network junctions. The cured OG/mPDA product inherently possesses higher thermal stability than the cured DGEBA/mPDA product based on higher maximum decomposition rate temperature, and higher char yield of the former. However, the existence of large fraction of the unreacted amine groups causes lower initial decomposition temperature of the OG/mPDA because it tends to decompose or volatilize on heating at relatively low temperature. The dielectric constant of the OG/mPDA material (2.31) is substantially lower than that of the DGEBA/mPDA (3.51) as a consequence the presence of nanoporous POSS cubes in the epoxy matrix. (C) 2004 Elsevier Ltd. All rights reserved.
Thermal and flame retardation properties of melamine phosphate-modified epoxy resins
(2004-06-01)
Chen, WY
;
Wang, YZ
;
Chang, FC
;
應用化學系
;
Department of Applied Chemistry
We have synthesized a series of epoxy resins containing melamine phosphate (MP) and investigated their thermal and flame retardation properties. MP functions as a hardener and a flame retardant or as an additive of the cured epoxy resin to enhance flame retardation properties of epoxy resins. The reactions of DGEBA cured in the presence of MP were monitored by NMR and FTIR. Our results show that in both reactive and additive modes, MP is effective in increasing limiting oxide index (LOI) and the char yields of epoxy resins at lower phosphorous content. We observed that flame retardation by MP in its reactive mode is better than in its additive mode; the same phenomenon was found also for the glass-transition temperature (T-g). Thermogravimetric analysis (TGA) demonstrated that epoxy resins containing MP decompose at relatively lower temperatures than those lacking MP; this decomposition results in a protective layer forming that prevents the epoxy resins from decomposing further by combustion.