Showing papers by "Chung Yuan Christian University published in 1994"
TL;DR: In this paper, a voltage-mode filter employing three current-feedback amplifiers, two grounded capacitors and three floating resistors is presented, which realises notch, low-pass and bandpass signals from the same configuration, no requirements for component matching conditions, orthogonal control of ωo and Q, and the use of two ground capacitors ideal for IC implementation.
Abstract: A voltage-mode filter employing three current-feedback amplifiers, two grounded capacitors and three floating resistors is presented. The proposed circuit offers the following advantages: realisation of notch, lowpass and bandpass signals from the same configuration, no requirements for component matching conditions, orthogonal control of ωo and Q, and the use of two grounded capacitors ideal for IC implementation, and low active and passive sensitivities and cascadability.
90 citations
TL;DR: A speed controller considering the effects of parameter variations and external disturbance for indirect field-oriented induction motor drives is proposed in this paper and an integral plus proportional (IP) controller is quantitatively designed to match the prescribed speed tracking specifications.
Abstract: A speed controller considering the effects of parameter variations and external disturbance for indirect field-oriented induction motor drives is proposed in this paper. First a microprocessor-based indirect field-oriented induction motor drive is implemented and its dynamic model at nominal case is estimated. Based on the estimated model, an integral plus proportional (IP) controller is quantitatively designed to match the prescribed speed tracking specifications. Then a dead-time compensator and a simple robust controller are designed and augmented to reduce the effects of parameter variations and external disturbances. The desired speed tracking control performance of the drive can be preserved under wide operating range, and good speed load regulating performance can also be obtained. Theoretic basis and implementation of the proposed controller are detailedly described. Some simulated and experimental results are provided to demonstrate the effectiveness of the proposed controller. >
74 citations
TL;DR: The control systems for spacecraft with either reaction wheels or gas jets being used as attitude controllers are proven to be controllable in this study, and some insight is given into the attitude-orbit coupling effects.
Abstract: The configuration space for rigid spacecraft systems in a central gravitational field can be modeled by SO(3)/spl times/ IR/sup 3/, where the special orthogonal group SO(3) represents the attitude dynamics and IR/sup 3/ is for the orbital motion. The attitude dynamics of the spacecraft system is affected by the orbital elements through the well-known gravity-gradient torque. On the other hand, the effects of attitude-orbit coupling can also possibly be used to alter orbital motions by controlling the attitude. This controllability property is the primary issue of this paper. The control systems for spacecraft with either reaction wheels or gas jets being used as attitude controllers are proven in this study to be controllable. Rigorously establishing these results necessitates starting with the formal definitions of controllability and Poisson stability. It is then shown that if the drift vector field of the system is weakly positively Poisson stable and the Lie algebra rank condition is satisfied, controllability can be concluded. The Hamiltonian structure of the spacecraft model provides a natural route of verifying the property of weakly positive Poisson stability. Accordingly, the controllability is obtained after confirming the Lie algebra rank condition. Developing a methodology in deriving Lie brackets in the tangent space of T(SO(3)/spl times/IR/sup 3/), i.e., the second tangent bundle is thus deemed necessary. A general formula is offered for the computation of Lie brackets of second tangent vector fields in TT(SO(3)/sup m//spl times/IR/sup n/), in light of its importance in the fields of mechanics, robotics, optimal control, and nonlinear control, among others. With these tools, the controllability results can be proved. The analysis in this paper gives some insight into the attitude-orbit coupling effects and may potentially lead towards new techniques in designing controllers for large spacecraft systems. >
74 citations
TL;DR: The most successful descriptions of such nuclei have neglected the many-body nature of the problem, replacing it instead with some form of single-particle field, often deformed, always violating fundamental symmetries that must be restored through projection.
Abstract: The bulk of contemporary research in nuclear structure physics deals with nuclei that are at least moderately collective in their low-lying statesThese are usually well removed from closed shells and constitute a difficult theoretical problem The most successful descriptions of such nuclei have neglected the many-body nature of the problem, replacing it instead with some form of single-particle field, often deformed, always violating fundamental symmetries that must be restored through projection Such approaches allow calculations that otherwise would have been impossible, and have been central to the rapid advance in quantitative descriptions of nuclear structure
71 citations
TL;DR: In this article, a single-resistance-controlled/voltage-controlled oscillator using three current conveyors, two grounded capacitors and three grounded resistors is presented.
Abstract: A novel single-resistance-controlled/voltage-controlled oscillator using three current conveyors, two grounded capacitors and three grounded resistors is presented. The proposed circuit offers the following advantageous features: employment of three grounded resistors for ease of adjustment, independent oscillation control through a single grounded resistor, independent frequency control through a single grounded resistor, employment of two grounded capacitors ideal for integration, ease of convertibility into a voltage-controlled oscillator, and very good frequency stability.
65 citations
TL;DR: Three approaches to estimate the parameters of a mixture of normal distributions are described, one based on a modification of the expectation maximization algorithm to compute maximum likelihood estimates, another makes use of the fuzzy c-means clustering algorithms, and the third is based on the penalized fuzzy c,means clustersering algorithms.
37 citations
TL;DR: In this article, a universal active current filter with three inputs was proposed, which contains only four current conveyors, two grounded capacitors and only two grounded resistors and has a simpler structure.
Abstract: A novel universal active current filter with three inputs which contains only four current conveyors, two grounded capacitors and only two grounded resistors and has a simpler structure than the previous one with three inputs which was proposed by Chang and Chen in 1991 is presented. The circuit is ideal for integration and has very low passive sensitivities.
37 citations
TL;DR: A simple and versatile series-impedance simulator with one plus-type second-generation current conveyor (CCII+) is presented in this paper, where the simulator is based on a simple simulator with two plus-types.
Abstract: A simple and versatile series-impedance simulator with one plus-type second-generation current conveyor (CCII+) is presented.
34 citations
TL;DR: The convergence rate of posterior risk of the fuzzy generalized NNR is exponentially fast, which means the algorithm can be described as a unified approach to a variety of fuzzy k-NNR's.
Abstract: tizzy k nearest neighbor rule (k-NNR) has been applied in a variety of substantive areas. Yang and Chen (l) described a fuzzy generalized k-NN algorithm which is a unified approach to a variety of fuzzy k-NNR's. They created the strong consistency of posterior risk of the fuzzy generalized NNR. In this paper, we give their convergence rate. That is, the convergence rate of posterior risk of the fuzzy generalized NNR is exponentially fast.
29 citations
01 Sep 1994
TL;DR: Two mathematical formulation models developed are presented and an example is shown in this paper referring to the either one of performance criteria.
Abstract: The purpose of this research is to consider the operational scheduling problem and the determination of production routing with alternate process plans simultaneously such that the advantages of routing flexibility are expected. The problem is formulated by using 0–1 integer programming regarding to the performance measure of either the minimum of the absolute deviation of meeting due date or the minimum of total completion time. The approach of mathematical programming generates the optimal schedule, rather than near optimal schedule or a better schedule, to meet the selected criterion. Two mathematical formulation models developed are presented and an example is shown in this paper referring to the either one of performance criteria.
27 citations
29 Jun 1994
TL;DR: Based on differential geometric control theory, the proposed autopilot offers the potential for improving the level of safety and the performance over those autopilot designs based on linearized models, and according to the concept of the proportional navigation, but under milder constraint, a new guidance law is proposed to intercept a nonmaneuvering target in the aerial engagement scenario as mentioned in this paper.
Abstract: In this paper, both guidance law and autopilot for the bank-to-turn (BTT) terminal homing missiles have been developed and been successfully integrated. Based on differential geometric control theory, the proposed autopilot offers the potential for improving the level of safety and the performance over those autopilot designs based on linearized models. And, according to the concept of the proportional navigation, but under milder constraint, a new guidance law is proposed to intercept a nonmaneuvering target in the aerial engagement scenario. To demonstrate the efficiency of our autopilot and guidance law, the computer simulation of the BTT missile is illustrated in several engagement scenarios and shows the satisfactory results.
TL;DR: In this article, a series of novel thermotropic liquid crystalline poly(imide-carbonate)s were prepared by melt polycondensation from various arylene or alkylene bis(phenylcarbonate), by using N,N′-bis(hydroxyethyl)pyromellitimide and N, N′-bi(hydroxpropyl)pyromeide as monomers.
Abstract: Two series of novel thermotropic liquid crystalline poly(imide-carbonate)s were prepared by melt polycondensation from various arylene or alkylene bis(phenylcarbonate)s by using N,N′-bis(hydroxyethyl)pyromellitimide and N,N′-bis(hydroxypropyl)pyromellitimide as monomers. Thermotropic liquid crystalline properties were characterized by a polarizing microscope with a heating stage and a differential scanning calorimeter (DSC). Nematic melts were found for the synthesized aromatic poly(imide-carbonate)s. In order to investigate whether the pyromellitimide unit could be used as a mesogenic unit for preparing LC polymers, a series of aliphatic poly(imide-carbonate)s was prepared in this study. However, no significant LC textures were found under the observation by polarizing microscope. It was suggested that the aspect ratio of the pyromellitimide unit was too short to form liquid crystalline poly(imide-carbonate)s. In addition, it was interesting that the aliphatic poly(imide-carbonate)s with a longer spacer (n = 3) in the pyromellitimide unit showed better crystallinity. Thermostabilities of all synthesized poly(imide-carbonate)s were measured by thermogravimetric analysis (TGA). © 1994 John Wiley & Sons, Inc.
TL;DR: Spiropyrazolines are obtained from the tandem reactions of one molecular of azide and three molecules of alkyl vinyl ketone as discussed by the authors, and they have two types of structures: one has an intramolecular hydrogen bond the hydroxyl proton and the acetyl oxygen.
TL;DR: A new isoprenylated aurone, broussoaurone A [5-(γ,γ-dimethylallyl)-6,3′,4′-trihydroxyaurone], was isolated and characterized from the cortex of Formosan Broussonetia papyrifera as discussed by the authors.
TL;DR: In this article, a series of novel azomethinediols, benzene 1,4-di(4-iminohydroxyphenoxy-n-alkanol)s, were prepared from 4-[4-hydroxybenzylideneamino)phenyliminomethyl] phenol with 2-chloroethanol, 3-bromopropanol, 6- bromohexanol, respectively.
TL;DR: In this article, an optical heterodyne polarized interferometer and lock-in technique was used to probe the concentration of dissolved chiral media in order to determine the angle of rotation.
TL;DR: In this article, the authors studied strain-induced band splittings of ZnSe/GaAs and Zn1−xMnxSe/GAAs epilayers of 0.064-3 μm thickness by reflectance and polarized photoluminescence.
Abstract: We studied strain‐induced band splittings of ZnSe/GaAs and Zn1−xMnxSe/GaAs epilayers of 0.064–3 μm thickness by reflectance and polarized photoluminescence. Polarized photolumi‐ nescence was found particularly useful in optical transition identification. The spectacular difference in magnetic field sensitivity of heavy hole and light hole exciton in ZnMnSe is also very helpful in transition identification. The evaluated heavy‐light hole band splitting is in general accordance with previous data. An exceptionally strong variation of the strain with epilayer thickness is observed in the thickness range 0.5–2 μm.
TL;DR: A silica-based adsorbent for affinity chromatography of serine protease was prepared by bonding p-aminobenzamidine (pABZ) to aminopropyl silica as discussed by the authors.
Abstract: A silica-based adsorbent for affinity chromatography of serine protease was prepared by bonding p-aminobenzamidine (pABZ) to aminopropyl silica. Silanization of silica with both γ-aminopropyltrimethoxysilane and γ-amino-propyltriethoxysilane under anhydrous conditions led to a monolayer density of primary amino groups. The aminopropyl silica was converted to primary hydroxylcontaining silica via diazotization, and consequently activated with p-nitrophenyl chloroformate and immobilized with ligand pABZ. The resultant silica–pABZ has a ligand density of 13.8 μmol g−1. Pyridine was indicated by the data to increase the reactivity of the chloroformate toward the hydroxyl group more efficiently than 4-dimethylaminopyridine. Two stages of adsorption were found in batch adsorption of trypsin with an equilibrium adsorption isotherm of the Langmuir type. When the chromatographic column packed with this silica–p ABZ was operated under a higher flow rate (2·33 cm3 min−1) and with 3 g dm−3 of crude urokinase as the influence, the yield was 55%. Both the flow rate and the concentration of the crude protein were shown, by measuring the dynamic binding capacity from chromatographic experiments, to be the factors which influenced the chromatographic efficiency.
TL;DR: In this paper, the two-dimensional renormalization map of the diamond-hierarchical Ising model in an external field is given, and pictures of the distribution of zeros of the partition function in the complex plane of temperature for varying values of coupling constant and external field are shown.
Abstract: The two-dimensional renormalization map of the diamond-hierarchical Ising model in an external field is given, and pictures of the distribution of zeros of the partition function in the complex plane of temperature for varying values of coupling constant and external field are shown. Critical exponents of the model are found, and results are different from those of the Ising model on a two- or three-dimensional regular lattice.
TL;DR: In this paper, nonlinear evolution equations derived by the integral method are used to study the inertial effect on rupture process of a thin liquid film, and nonlinear numerical results show that inertial effects accelerate the rupture process, and this phenomenon is explicit in the situation of weak effect of van der Waals potential.
TL;DR: This paper establishes asymptotic normality of the FCM clustering procedures, that is, the asymPTotic distribution of the normalized optimal cluster centers is multivariate normal.
Abstract: A family of fuzzy c-partitions of a set X in an s-dimensional Euclidean space known as fuzzy c-means (FCM) clustering procedures has been widely used for the problem of clustering the set X of objects into groups of similar individuals. Suppose that the set X is a simple random sample of observations from a population with probability measure P. Now choose ever larger finite random samples from P. We are interested in the stochastically asymptotic properties of the FCM. In this paper, we establish asymptotic normality of the FCM clustering procedures. That is, the asymptotic distribution of the normalized optimal cluster centers is multivariate normal.
01 Jan 1994-Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology
TL;DR: In this paper, an optical fiber sensor system based on dual beam speckle interferometry is presented, which takes advantage of simple optical components and fibers through a signal processing technique capable of measuring vibration displacement components.
Abstract: An optical fiber sensor system based on dual beam speckle interferometry is presented. The system provides a noncontact method of very small vibration displacement real-time measurement. It takes advantage of simple optical components and fibers through a signal processing technique capable of measuring vibration displacement components. The theoretical analysis and experimental systems are described. Experimental results show that the in-plane vibration spectrum can be easily established.
TL;DR: In this article, ordinary concrete samples made from the most common Type I portland cement as well as some uncommon glossy-looking concrete lumps collected from a real fire scene were examined by using thermogravimetry (TG), differential thermal analysis (DTA), X-ray diffraction and scanning electron microscope/energy dispersive Xray spectrometry (SEM/EDX) with the aid of an unsealed furnace.
09 Nov 1994
TL;DR: A program generator takes an extended finite state machine as a domain model and generates a group of C++ classes needed for an implementation and generates an object for each state of the FSM.
Abstract: A program generator for communication protocol software is presented. This program generator takes an extended finite state machine as a domain model and generates a group of C++ classes needed for an implementation. In the program generator, an object is generated for each state of the FSM. In a given state, for each interface event that triggers a state transition from the state to another state or back to itself, a member function (or called method) is created for the state object. The actions associated with a state transition constitute bodies of the member function corresponding to the interface event that triggers the transition. The program generator now includes a state machine editor, a program editor, and a class library. Incremental implementation is also supported by the program generator. >
Abstract: A multirate robust servomechanism controller design for a linear time delay system is presented. The proposed controller is constructed by using a preparatory continuous internal model followed by a multirate error feedback compensator. An optimal algorithm for choosing the controller parameters is also derived. The algorithm is derived by minimizing a squared deviation error performance index, and the practical optimal solution can simply be solved from a discrete-time algebraic Riccati equation. A distinctive feature of the algorithm is that an optimal pulse compensation is also employed to improve the transient characteristics. Such a pulse compensation tends to eliminate the undesired influence arising from the initial deviation from the ultimate steady-state. In particular, if the initial deviation from the ultimate steady-state is known, then the optimal pulse compensation can drive the system into the steady-state in a time no larger than the input delay time plus the sampling period.
TL;DR: It was found that the analytical performance is most dependent on the identity of theMetal used for complexation; the concentration of the metal was of secondary importance and the column temperature less important still.
Abstract: The separation of the D and L enantiomers of eighteen essential α amino acids has been investigated by ligand-exchange chromatography (LEC). The effect of column temperature on the retention times and resolution of individual amino acid enantiomers has been studied by varying the temperature from 25 to 50 °C for a mobile phase containing Cu2+ ions. By use of a temperature of 50 °C and Zn2+ in the mobile phase, eight of the eighteen amino acid enantiomers can be resolved sufficiently well for practical application. Only phenylalamine, tyrosine, and tryptophan can be separated by use of Ni2+ as complexation metal at 50 °C. LEC has been used to monitor the decarboxylation of racemic DL-aspartic acid byPseudomonas dacunhae. Analysis of DL amino acid enantiomers in different media was performed at column temperatures of 30 and 50°C by addition of 0.125 mM Cu2+ to the aqueous mobile phase. It was found that the analytical performance is most dependent on the identity of the metal used for complexation; the concentration of the metal was of secondary importance and the column temperature less important still.
29 Jul 1994
TL;DR: An axiomatization of confidence transfer - a known conditioning scheme - is given from the perspective of expectation-based inference in the sense of Gardenfors and Makinson and the notion of belief independence is used to filter out different proposals of possibilistic conditioning rules.
Abstract: We give an axiomatization of confidence transfer - a known conditioning scheme - from the perspective of expectation-based inference in the sense of Gardenfors and Makinson. Then, we use the notion of belief independence to "filter out" different proposals of possibilistic conditioning rules, all are variations of confidence transfer. Among the three rules that we consider, only Dempster's rule of conditioning passes the test of supporting the notion of belief independence. With the use of this conditioning role, we then show that we can use local computation for computing desired conditional marginal possibilities of the joint possibility satisfying the given constraints. It turns out that our local computation scheme is already proposed by Shenoy. However, our intuitions are completely different from that of Shenoy. While Shenoy just defines a local computation scheme that fits his framework of valuation-based systems, we derive that local computation scheme from Π(β) = Π(β) * Π(α) and appropriate independence assumptions, just like how the Bayesians derive their local computation scheme.
TL;DR: An accurate fringe center detection technique based on sub-pixel resolution using the fringe projection method is presented and an optimum reconstruction filter is developed which has low sensitivity to noise.
TL;DR: The microscopic origin of deformation for heavy nuclei is discussed in this paper, where it is shown that the systematic features of nuclear deformation are determined primarily by filling of the normal-parity shell model orbitals of the valence shells, and that the abnormal parity orbitals play crucial but subsidiary roles.
Abstract: The microscopic origin of deformation for heavy nuclei is discussed. Evidence is presented that the systematic features of nuclear deformation are determined primarily by filling of the normal-parity shell model orbitals of the valence shells, and that the abnormal-parity orbitals play crucial but subsidiary roles. This is in accord with the point of view underlying the Fermion Dynamical Symmetry Model. In addition, we demonstrate that the deformation systematics of the FDSM are consistent with those of the Nilsson model, despite their very different starting points, and that the assumptions of the FDSM are consistent with the assertion that the n-p quadrupole-quadrupole residual interaction is the essential reason for deformation. Finally, application of the same principles to superdeformation suggests that abnormal parity orbitals have a much more direct influence on superdeformation than on normal deformation.