Showing papers by "Chung Yuan Christian University published in 2006"

A bidirectional DC–DC converter for fuel cell electric vehicle driving system

Abstract: This paper presents a power converter for a fuel cell electric vehicle driving system. A new bidirectional, isolated topology is proposed in consideration of the differing fuel cell characteristics from traditional chemical-power battery and safety requirements. The studied converter has the advantages of high efficiency, simple circuit, and low cost. The detailed design and operating principles are analyzed and described. The simulation and experimental waveforms for the proposed converter are shown to verify its feasibility.

A Customized Human Fall Detection System Using Omni-Camera Images and Personal Information

Abstract: This paper proposes a new approach to detect the fall of the elderly. The detection system uses a MapCam (omni-camera) to capture images and performs image processing over the images. The personal information of each individual is considered in the processing task. The MapCam is used to capture 360deg scenes simultaneously and eliminate any blind viewing zone. The personal information is combined into the system and makes it smarter by customizing the system for each individual. With personal information such as height, weight, and electronic health history, we can adjust the detection sensitivity on a case by case basis to reduce unnecessary alarms, and put more attention on the elderly with special diseases or conditions. We perform a simple experiment to verify the feasibility of our approach. The experimental results show that the successful rates of fall detections with and without personal information are 79.8% and 68%, respectively. The Kappa value of the system is 0.798 which is higher than 0.75, showing that we have a reliable system

Wireless Health Care Service System for Elderly With Dementia

Abstract: The purpose of this paper is to integrate the technologies of radio frequency identification, global positioning system, global system for mobile communications, and geographic information system (GIS) to construct a stray prevention system for elderly persons suffering from dementia without interfering with their activities of daily livings. We also aim to improve the passive and manpowered way of searching the missing patient with the help of the information technology. Our system provides four monitoring schemes, including indoor residence monitoring, outdoor activity area monitoring, emergency rescue, and remote monitoring modes, and we have developed a service platform to implement these monitoring schemes. The platform consists of a web service server, a database server, a message controller server, and a health-GIS (H-GIS) server. Family members or volunteer workers can identify the real-time positions of missing elderly using mobile phone, PDA, Notebook PC, and various mobile devices through the service platform. System performance and reliability is analyzed. Experiments performed on four different time slots, from three locations, through three mobile telecommunication companies show that the overall transaction time is 34 s and the average deviation of the geographical location is about 8 m. A questionnaire surveyed by 11 users show that eight users are satisfied with the system stability and 10 users would like to carry the locating device themselves, or recommend it to their family members

Crosslinked epoxy materials exhibiting thermal remendablility and removability from multifunctional maleimide and furan compounds

Abstract: Crosslinked polymeric materials, which exhibit thermal remendability and removability through Diels–Alder (DA) and retro-DA reactions, were obtained from using multifunctional maleimide and furan compounds as monomers. The synthesized monomers possess low melting points and good solubility in organo solvents to show excellent processing properties. The performance of DA and retro-DA reactions were demonstrated with DSC and FTIR measurements. High performance of thermal remendablility and removability of the crosslinked materials were observed with SEM and solvent tests. These materials were applicable in advanced encapsulants and structural materials. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 905–913, 2006

Electrophoretic Separation of Nanoparticles with a Discrete Number of Functional Groups

Abstract: A concept is describe that facilitates the modification of colloidal nanoparticles of different materials with an exactly known number of variable functional groups. In particular, a procedure for the surface functionalization of nanoparticles with a controlled number of mono- or bifunctional poly(ethylene glycol) (PEG) molecules of suitable chain length is reported. Conjugates of nanoparticles with one, two, and three PEG molecules per nanoparticle could be separated using gel electrophoresis. Molecules with additional functionalities could be conjugated to the free ends of the bifunctional PEG molecules. In this way the PEG molecules act as convenient spacers that allow for the sorting of nanoparticles with a discrete number of functional groups.

Fuzzy entropy on intuitionistic fuzzy sets

Abstract: In this article we exploit the concept of probability for defining the fuzzy entropy of intuitionistic fuzzy sets (IFSs). We then propose two families of entropy measures for IFSs and also construct the axiom definition and properties. Two definitions of entropy for IFSs proposed by Burillo and Bustince in 1996 and Szmidt and Kacprzyk in 2001 are used. The first one allows us to measure the degree of intuitionism of an IFS, whereas the second one is a nonprobabilistic-type entropy measure with a geometric interpretation of IFSs used in comparison with our proposed entropy of IFSs in the numerical comparisons. The results show that the proposed entropy measures seem to be more reliable for presenting the degree of fuzziness of an IFS. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 443–451, 2006.

Siloxane-modified epoxy resin–clay nanocomposite coatings with advanced anticorrosive properties prepared by a solution dispersion approach

Abstract: A series of polymer–clay nanocomposite (PCN) materials that consist of siloxane-modified epoxy resin and inorganic nanolayers of montmorillonite (MMT) clay has been prepared through a thermal ring opening polymerization using 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane as a curing agent. These PCN materials at low clay concentration in the form of coating on cold-rolled steel (CRS) were found to be much superior in corrosion protection over those of pure epoxy resin when tested for performance in a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current, and impedance spectroscopy in 5 wt.% aqueous NaCl electrolyte. The as-prepared materials were characterized by infrared spectroscopy, wide-angle X-ray diffraction, and transmission electron microscopy. After measurements, we found advanced protection against corrosion on CRS coupon compared to bulk epoxy resin. Molecular (e.g., O2, N2, and H2O) permeability of epoxy resin–clay nanocomposite membranes was found to be lower than that of bulk epoxy resin along with the loading of nanoclay based on the studies of gas and vapor permeability analysis. Moreover, the epoxy resin–clay nanocomposite materials have significant advantages over standard epoxy resins such as lower water absorption, lower cure shrinkage, moderate glass transition temperature (Tg), and higher tensile strength.

Charmless hadronic B decays involving scalar mesons: Implications on the nature of light scalar mesons

Abstract: The hadronic charmless $B$ decays into a scalar meson and a pseudoscalar meson are studied within the framework of QCD factorization. Based on the QCD sum rule method, we have derived the leading-twist light-cone distribution amplitudes of scalar mesons and their decay constants. Although the light scalar mesons ${f}_{0}(980)$ and ${a}_{0}(980)$ are widely perceived as primarily the four-quark bound states, in practice it is difficult to make quantitative predictions based on the four-quark picture for light scalars. Hence, predictions are made in the 2-quark model for the scalar mesons. The short-distance approach suffices to explain the observed large rates of ${f}_{0}(980){K}^{\ensuremath{-}}$ and ${f}_{0}(980){\overline{K}}^{0}$ that receive major penguin contributions from the $b\ensuremath{\rightarrow}ss\overline{s}$ process. When ${f}_{0}(980)$ is assigned as a four-quark bound state, there exist extra diagrams contributing to $B\ensuremath{\rightarrow}{f}_{0}(980)K$. Therefore, a priori the ${f}_{0}(980)K$ rate is not necessarily suppressed for a four-quark state ${f}_{0}(980)$. The predicted ${\overline{B}}^{0}\ensuremath{\rightarrow}{a}_{0}^{\ifmmode\pm\else\textpm\fi{}}(980){\ensuremath{\pi}}^{\ensuremath{\mp}}$ and ${a}_{0}^{+}(980){K}^{\ensuremath{-}}$ rates exceed the current experimental limits, favoring a four-quark nature for ${a}_{0}(980)$. The penguin-dominated modes ${a}_{0}(980)K$ and ${a}_{0}(1450)K$ receive predominant weak annihilation contributions. There exists a twofold experimental ambiguity in extracting the branching ratio of ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{\overline{K}}_{0}^{*0}(1430){\ensuremath{\pi}}^{\ensuremath{-}}$, which can be resolved by measuring other ${K}_{0}^{*}(1430)\ensuremath{\pi}$ modes in conjunction with the isospin symmetry consideration. Large weak annihilation contributions are needed to explain the ${K}_{0}^{*}(1430)\ensuremath{\pi}$ data. The decay ${\overline{B}}^{0}\ensuremath{\rightarrow}{\ensuremath{\kappa}}^{+}{K}^{\ensuremath{-}}$ provides a nice ground for testing the 4-quark and 2-quark nature of the $\ensuremath{\kappa}$ meson. It can proceed through $W$-exchange and hence is quite suppressed if $\ensuremath{\kappa}$ is made of two quarks, while it receives a tree contribution if $\ensuremath{\kappa}$ is predominately a four-quark state. Hence, an observation of this channel at the level of $\ensuremath{\gtrsim}{10}^{\ensuremath{-}7}$ may imply a four-quark assignment for the $\ensuremath{\kappa}$. Mixing-induced $CP$ asymmetries in penguin-dominated modes are studied and their deviations from $\mathrm{sin} 2\ensuremath{\beta}$ are found to be tiny.

Supplier selection using combined analytical hierarchy process and grey relational analysis

Abstract: Purpose – The purpose of this paper is to develop an evaluation model considering the qualitative and quantitative criteria for supplier selection in an outsourcing manufacturing organization.Design/methodology/approach – In this paper, the authors propose an integrated model by combining the analytical hierarchy process (AHP) and grey relational analysis (GRA) into a single evaluation model. The model is illustrated with a case study of a notebook computer manufacturer to demonstrate the effectiveness of this integrated model.Findings – Through the proposed model, it is possible to effectively integrate the specialized knowledge and experience of each dispersed evaluator, and the quantitative data to select the best suppliers for cooperation.Originality/value – The decision‐aiding software (AHP‐GRA model) has been implemented in Excel to automate the supplier selection process. This can widely apply the integrated model for the industry.

The impact of human resource management practices on the implementation of total quality management

Abstract: Purpose – The perceived advantages of the implementation of TQM are generating improved quality and efficiency, increasing customer satisfaction, thus improving competitiveness. However, there is a high failure rate in the implementation of TQM. The key issue in this regard is that companies have devoted relatively little attention to human resources management (HRM). Several academics and practitioners have asserted that synergy and congruence among HRM practices are critical to the implementation of TQM. However, there is relatively little empirical evidence to support this contention. The purpose of this research is to conduct an empirical study on high‐tech firms, in order to analyse the impacts of HRM practices on the implementation of TQM.Design/methodology/approach – In this study, a research framework related to HRM practices, TQM practices, and quality performances was developed. Based on the framework, a questionnaire was designed and sent to the HR managers or chief executive officers (CEOs) of...

Fluorecent staining for study of extracellular polymeric substances in membrane biofouling layers.

Abstract: Membrane biofouling by microbial products adversely impacts the feasibility of adopting membrane bioreactors (MBRs) for treating wastewater. The fouling layer structure determines the pressure drop across the fouling layer. Three-dimensional distributions of nucleic acids, proteins, alpha-D-GLUCOPYRANOSE POLYSACCHARIDES, AND B-D-glucopyranose polysaccharides in the fouling layer formed on a mixed cellulose ester membrane were generated utilizing a quadruple staining protocol combined with confocal laser scanning microscopy (CLSM). For the first time, this study constructed a three-dimensional volumetric grids model representing the fouling layer structure on the basis of a series of CLSM images. Quantitative structural information about the fouling layer was extracted from the CLSM images.

LMI-based Integral fuzzy control of DC-DC converters

Abstract: In this paper, we propose a T-S fuzzy controller which combines the merits of: i) the capability for dealing with nonlinear systems; ii) the powerful LMI approach to obtain control gains; iii) the high performance of integral controllers; iv) the workable rigorous proof for exponential convergence of error signals; and v) the flexibility on tuning decay rate. The output regulation problems of a basic buck converter and a zero-voltage-transition (ZVT) buck converter are used as application examples to illustrate the control performance of the proposed methodology. First, we consider a general nonlinear system which can represent the large-signal models of the converters. After introducing an added integral state of output regulation error and taking coordinate translation on an equilibrium point, the resulting augmented system is represented into a Takagi-Sugeno (T-S) fuzzy model. Then, the concept of parallel distributed compensation is applied to design the control law whereby the control gains are obtained by solving linear matrix inequalities (LMIs). An interesting result is that the obtained control law is formed only by the linear state feedback signals weighted by grade functions. In addition, the robustness analysis is carried out when uncertainty and disturbance are taken into consideration. The performance of numerical simulations and practical experiments results is satisfactory.

Output Tracking Control for Fuzzy Systems Via Output Feedback Design

Abstract: Fuzzy observer-based control design is proposed to deal with the output tracking problem for nonlinear systems. For the purpose of tracking design, the new concept of virtual desired variables and, in turn the so-called generalized kinematics are introduced to simplify the design procedure. In light of this concept, the design procedure is split into two steps: i) Determine the virtual desired variables from the generalized kinematics; and ii) Determine the control gains just like solving linear matrix inequalities for stabilization problem. For immeasurable state variables, output feedback design is proposed. Here, we focus on a common feature held by many physical systems where their membership functions of fuzzy sets satisfy a Lipschitz-like property. Based on this setting, control gains and observer gains can be designed separately. Moreover, zero tracking error and estimation error are concluded. Three different types of systems, including nonlinear mass-spring systems, dc-dc converters, and induction motors are considered to demonstrate the design procedure. Their satisfactory simulation results verify the proposed approach

Dynamic mold surface temperature control using induction heating and its effects on the surface appearance of weld line

Abstract: Electromagnetic induction heating combined with coolant cooling is used to achieve dynamic mold surface temperature control. A simulation tool was also developed by integration of both thermal and electromagnetic analysis modules of ANSYS, and capability and accuracy were verified experimentally. To evaluate the feasibility and efficiency of induction heating on the mold surface temperature control, a mold plate (roughly about an inset size of cellular phone housing) with four cooling channels was utilized for two demo experiments with varying mold surface temperature between 110 and 180°C, and 110 and 200°C, respectively. During induction heating/cooling, it takes 4 s to increase mold surface temperature from 110 to 200°C and 21 s for mold surface to return to 110°C. The mold plate surface temperature can be raised at about 22.5°C and cooled down at 4.3°C/s within the aforementioned temperature range. Mold plate temperature distribution exhibits good uniformity as well in all stages of the heating/cooling process. Finally, mold surface temperature of a double-gated tensile test part mold was induction heated to above glass transition temperature for few seconds prior to melt injection. The surface mark of weld line was eliminated, and the associated weld line strength enhanced. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1174–1180, 2006

Suppression of field screening in nematic liquid crystals by carbon nanotubes

Abstract: Transient currents induced by the polarity reversal of an applied dc electric field have been measured in planar-aligned nematic liquid-crystal cells. Experimental results indicate that a minute addition of carbon nanotubes as a dopant leads to a reduction of the ion concentration and thus suppresses the undesired field-screening effect. Observed simultaneously is a higher charge mobility in the doped cells in the presence of a strong field. Such increase of mobility, in comparison with that of undoped counterparts, is attributed to the parallel alignment of both the long axis of carbon nanotubes and the nematic director along the electric field.

Research on the effects of team teaching upon two secondary school teachers

Abstract: Background The implementation of the nine-year integrated curriculum in the primary and secondary schools of Taiwan represented, in practice, a great change to the nature of school teaching. This was mainly due to the fact that the new scheme for the curriculum required teachers to collaborate with one another, when they had been teaching students independently for most of their teaching career. Purpose The purpose of this research was to study the effects of team teaching upon two 8th-grade teachers in the field of mathematics. The specific research question was student performance and teacher perceptions concerning team teaching. Programme description Team teaching involves two or more teachers whose primary concern is the sharing of teaching experiences in the classroom, and co-generative dialoguing with each other. They take collective responsibility for maximizing learning to teach, or becoming better at teaching, while providing enhanced opportunities for their students to learn. Sample The subjects...

Rapid mold temperature variation for assisting the micro injection of high aspect ratio micro-feature parts using induction heating technology

Abstract: Hot embossing and injection molding are popular methods to duplicate micro features formed during polymer micro-fabrication of MEMS devices. However, both methods face challenges in filling the polymer melt completely into a micro-featured geometry of a high aspect ratio. In this study, electromagnetic induction heating combined with water cooling is used to achieve rapid mold surface temperature control during the micro-feature injection molding process. A CAE simulation was also developed through integration of both thermal and electromagnetic analysis modules of ANSYS, and its capability and accuracy were verified experimentally. Efficiency evaluations of induction heating and the uniformity of mold temperature control were conducted on a micro-featured mold. This mold was designed with a micro channel array of 30–50 µm in width and 120 and 600 µm in depth, corresponding to aspect ratios ranging from about 2.4 to 12. The accuracies of the micro channels in molded PMMA parts can be used to evaluate the effect of mold temperature on replication accuracy. It was found that rapid mold surface heating with temperature rising from 60 °C to between 100 °C and 140 °C by induction heating requires 2–3.5 s, while the mold temperature returns to 60 °C in about 70–110 s. The simulated mold surface temperature results are consistent with measured results. Achieving the same temperature variation by switching circulation coolants of different temperatures requires at least 7 min. The simulation also reveals that the electromagnetic wave can penetrate into the bottom of the micro channel and results in only about a 2 °C difference in temperature uniformity. For mold temperatures of 100 °C, 120 °C and 140 °C, the molded channel depths were 94.9 µm, 105.4 µm and 116.0 µm, respectively, when the ideal channel depth was 120 µm. When the channel depth is 600 µm, the mold temperature must exceed 120 °C, so that reasonable accuracy in micro-feature replication can be achieved. Our results to date indicate that the aspect ratio for molded PMMA micro channels can be as high as 12. Efficient mold temperature variation by induction heating to improve the replication accuracy in molding micro features is successfully illustrated.

Some expansion formulas for a class of generalized Hurwitz–Lerch Zeta functions

Abstract: By making use of fractional calculus, the authors present a systematic investigation of expansion and transformation formulas for several general families of the Hurwitz–Lerch Zeta functions. Relevant connections of the results discussed here with those obtained in earlier works are also indicated precisely.

Quadrature Oscillators with Grounded Capacitors and Resistors Using FDCCIIs

Abstract: Two current-mode and/or voltage-mode quadrature oscillator circuits each using one fully-differential secondgeneration current conveyor (FDCCII), two grounded capacitors, and two (or three) grounded resistors are presented. In the proposed circuits, the current-mode quadrature signals have the advantage of high-output impedance. The oscillation conditions and oscillation frequencies are orthogonally (or independently) controllable. The current-mode and voltage-mode quadrature signals can be simultaneously obtained from the second proposed circuit. The use of only grounded capacitors and resistors makes the proposed circuits ideal for integrated circuit implementation. Simulation results are also included.

Anticorrosively enhanced PMMA–SiO2 hybrid coatings prepared from the sol–gel approach with MSMA as the coupling agent

Abstract: A series of sol–gel derived organic–inorganic hybrid coatings consisting of organic poly(methyl methacrylate) (PMMA) and inorganic silica (SiO2) were successfully synthesized by using 3-(Trimethoxysilyl)propyl methacrylate as a coupling agent. In this work, MSMA is first copolymerized with methyl methacrylate monomer at specific feeding ratio by using benzoyl peroxide (BPO) as initiator. Subsequently, the as-prepared copolymer (i.e., sol–gel precursor) is then cohydrolyzed with various contents of tetraethyl orthosilicate (TEOS) to afford chemical bondings to the forming silica networks, giving a series of hybrid sol–gel coatings. Transparent organic–inorganic hybrid sol–gel coatings with different contents of silica are always achieved. The as-synthesized hybrid sol–gel materials were subsequently characterized by Fourier-Transformation infrared (FTIR) spectroscopy and transmission electron microscopy (TEM). The hybrid sol–gel coatings with low silica loading (e.g., 5 wt.%) on cold-rolled steel (CRS) coupons were found much superior in anticorrosion efficiency over those of neat PMMA based on a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current, and corrosion rate in 5 wt.% aqueous NaCl electrolyte. The enhancement of corrosion protection effect of hybrid sol–gel coatings may be due to the increase of adhesion strength of hybrid sol–gel coatings on CRS coupons relative to neat PMMA, which was further evidenced by the Scotch tape test evaluation. The increase of adhesion strength of hybrid sol–gel coatings on CRS coupons may be attributed to the formation of Fe–O–Si covalent bonds at the interface of coating/CRS system based on the FTIR–RAS (reflection absorption spectroscopy) studies. Effects of the material composition on the thermal stability, mechanical strength, wettability, and surface morphology of neat copolymer and a series of hybrid sol–gel materials, in the form of coating/film, were also studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), hardness tests, contact angle measurement, and atomic force microscopy (AFM), respectively.

ISFET performance enhancement by using the improved circuit techniques

Abstract: An approach to enhance accuracy of the output signal obtained from ISFET interface electronics due to the body effect is proposed. Based on an MOS drawing the same drain current as the ISFET, the scheme allows reduction of influence of body effect. The presented readout interface improves the accuracy of pH measurements, while maintaining operation at constant drain-source voltage and current condition. Using only one ISFET with a differential output configuration, we obtained temperature-dependency and long-term drift as well as common noise compensation. The proposed technique is simple and has a universal use for different ISFETs. In addition, a voltage-controlled dc offset error compensation circuit modulates the extracted signal to the desired dc level for the A/D converter for each sensor. Simulation and experimental results show a great effect on monolithic ISFET integration in CMOS technology.

Effect of Reactive Channel Functional Groups and Nanoporosity of Nanoscale Mesoporous Silica on Properties of Polyimide Composite

Abstract: Novel covalently bonded nanoscale mesoporous silica (NMS)/polyimide (ODPA−BAPP) nanocomposites were synthesized through the bridge 3-aminopropyltrimethoxysilane. Abundant reactive amino functional groups inside the mesopore channels of NMS can interconnect with numerous polyimide main chains, forming multilinked and complex NMS/PI networks. These multilinkages, NMS inherent nanoporosity, and the uniform dispersion of NMS in polyimide significantly improve thermal stability, mechanical properties, elongation, moisture absorption, and dielectric constant of these novel materials over those of neat polyimide. For instance, the storage modulus is increased by 160%, the decomposition temperature by 35.7 °C, and the glass transition temperature by 14.5 °C. The maximum elongation increases by 66%, hardly observed in other polyimide nanocomposites, probably because the covalent bond and NMS nanopore can absorb more energy than pristine poyimide before failure. The nanoporosity of the core of the NH2-NMS material ...

First-order allpass filter and sinusoidal oscillators using DDCCs

Abstract: A voltage-mode first-order allpass filter using one differential difference current conveyor (DDCC), one grounded capacitor and one floating resistor is presented. No passive component matching constraints are required. Because the output impedance of the proposed allpass filter is low, the output terminal can be directly connected to the next stage. Using the proposed first-order allpass filter as a basic building block, a new quadrature oscillator and even-phase sinusoidal oscillators can be obtained. The simulation results confirm the theoretical analysis.

Virtual Metrology Technique for Semiconductor Manufacturing

Abstract: IC metrology is a necessary means for measuring the fabrication performance in the semiconductor industry. It is significant for yield enhancement and process control. However, real-time monitoring of wafer production is required in recent years especially for the 300 mm semiconductor manufacturing. Therefore, virtual metrology (VM) is developed for the tide of demand. It is a novel technology to predict the process results based on the previous metrology measurements, instead of measuring practically. Consequently it can assist in achieving total quality management and enable run-to-run control. In this paper a systematic methodology for virtual metrology is proposed. This VM system which is mainly designed for the process subject to linear process drift consists of a piecewise linear neural network and a fuzzy neural network. Because many semiconductor processes exhibit inevitable steady drifts in nature, the design of piecewise linear neural network is to approximate the drift trend. In addition, the influence of process recipe on fabrication outcome is learned using the fuzzy neural network. The system has good generalization capability and performance. Thus, it provides an effective and economical solution for metrology prediction.