Showing papers by "Chung Yuan Christian University published in 1996"
TL;DR: In this article, a Tabu Search (TS) based solution algorithm is proposed to solve the capacitors placement problem in a radial distribution system, which considers the operating constraints of capacitors, load growth, capacity of the feeder and upper and lower bound constraints of voltage at different load levels.
Abstract: In this paper, the capacitor placement problem in a radial distribution system is formulated and solved by a Tabu Search (TS) based solution algorithm. The capacitor placement problem considers practical operating constraints of capacitors, load growth, capacity of the feeder and the upper and lower bound constraints of voltage at different load levels to minimize the investment cost of capacitors and system energy loss. A sensitivity analysis method is used to select the candidate installation locations of the capacitors to reduce the search space of this problem a priori. Comparison results of the TS method with the simulated annealing (SA) show that the proposed TS method can offer the nearly optimal solution to the capacitor placement problem within reasonable computing time.
235 citations
TL;DR: New types of fuzzy clustering procedures in dealing with fuzzy data are derived, called fuzzy c-numbers (FCN) clusterings, which construct these FCNs for U-type, triangular, trapezoidal and normal fuzzy numbers.
198 citations
TL;DR: This work aims to derive the complete solutions of three-dimensional realistic true proportional navigation for nonmaneuvering and maneuvering targets with varying closing speed by solving three coupled nonlinear second-order state equations describing the relative motion.
Abstract: True proportional navigation with varying closing speed is called realistic true proportional navigation, which is implemented in practice. Our main goal is to derive the complete solutions of three-dimensional realistic true proportional navigation for nonmaneuvering and maneuvering targets. Three coupled nonlinear second-order state equations describing the relative motion are solved analytically without any linearization for performance and trajectory analysis. Properties of three-dimensional realistic true proportional navigation such as capture region, range-to-go, time-to-go, and two aspect angles within spherical coordinates are all obtained in closed form. Furthermore, the two-player game between three-dimensional realistic true proportional navigation and threedimensional ideal proportional navigation is investigated analytically in the pursuit-evasion scenario, where a realistic true proportional navigation guided missile is designed to pursue an ideal proportional navigation guided target. It is found that an ideal proportional navigation guided target is much harder to intercept than a realistic true proportional navigation guided target. I. Introduction ROPORTIONAL navigation (PN) for short-range tactical misP siles is the optimal interceptive law in the sense of producing zero miss distance with the least integral square control effort. PN has been studied since the 1940s. During the four decades that followed, proportional navigation has been explored in many different ways, such as true proportional navigation, pure proportional navigation (PPN), generalized proportional navigation, realistic true proportional navigation (RTPN), and ideal proportional navigation It has long been recognized that there exists a significant difference in the way in which PN guidance law is analyzed and in the way in which it is implemented. Most analytical studies of PN assume that the closing velocity in the PN guidance law is constant, whereas in realistic situations, the instantaneous closing speed may be continuously estimated or measured using devices such as homing seekers with Doppler radar. To remove this difference, RTPN, which adapts to varying closing speed, has recently been proposed. Performance and trajectory analysis of two-dimensional RTPN was studied by
96 citations
TL;DR: In this article, the M3Y effective nucleon-nucleon interaction has been used to calculate the basic properties of asymmetric nuclear matter within a non-relativistic Hartree-Fock scheme.
90 citations
01 May 1996
TL;DR: In this paper, an induction-motor (IM) speed drive, with the application of an extended Kalman filter (EKF) and a proposed recursive least-square (RLS) estimator, is introduced.
Abstract: An induction-motor (IM) speed drive, with the application of an extended Kalman filter (EKF) and a proposed recursive least-square (RLS) estimator, is introduced. The rotor resistance of the IM is identified by the EKF, and the rotor inertia constant, the damping constant and the disturbed load torque of the IM are estimated by the proposed RLS estimator, which is composed of an RLS estimator and a torque observer. The integral proportional (IP) speed controller is on-line, designed according to the estimated rotor parameters. Then the observed disturbance torque is fed forward to increase the robustness of the induction-motor speed drive.
76 citations
02 Nov 1996
TL;DR: A 3-D elastic transformation which compensates for the non-rigid deformation of the chest that is seen in X-ray CT relative to PET images of the thorax showed an accurate alignment and reliable correlation of the detailed anatomy of the CT with the functional information of the PET images.
Abstract: Describes a 3-D elastic transformation which compensates for the non-rigid deformation of the chest that is seen in X-ray CT relative to PET images of the thorax. X-ray CT is widely used for detection and localization of lesions in the thorax. Whole Body PET with 18-FDG is accepted for staging and for measuring tumor response to therapy. The combination of these two modalities to locate metabolically active tumors in CT images should prove to be of significant value in lung cancer staging and treatment planning. Due to the differences in the acquisition conventions and scan duration, the subject's arms are positioned overhead for X-ray CT or at the side for PET, causing a change in the shape of the thorax, requiring non-rigid transformations to achieve proper registration. Techniques to register chest X-ray CT and Whole Body PET images were developed and evaluated. The accuracy of 3-D elastic transformation was tested by phantom study. Studies on patients with lung carcinoma were used to assess the technique for localizing 18-FDG uptake and for correlating PET transmission to X-ray CT images. Results showed that the elastic transformation provided an accurate alignment and reliable correlation of the detailed anatomy of the CT with the functional information of the PET images.
73 citations
TL;DR: The authors recommend that the second approach should be used on FDG PET images to correct for partial volume effects and to determine whether an apparent change in GM radiotracer concentration is truly due to metabolic changes.
Abstract: The use of positron emission tomography (PET) in quantitative fluorodeoxyglucose (FDG) studies of aging and dementia has been limited by partial volume effects. A general method for correction of partial volume effects (PVE) in PET involves the following common procedures: segmentation of MRI brain images into gray matter (GM), white matter (WM), cerebral spinal fluid (CSF), and muscle (MS) components: MRI PET registration; and generation of simulated PET images. Afterward, two different approaches can be taken. The first approach derives first a pixel-by-pixel correction map as the ratio of the measured image to the simulated image [with realistic full-width at half-maximum (FWHM)]. The correction map was applied to the MRI segmentation image. Regions of interest (ROI's) can then be applied to give results free of partial volume effects. The second approach uses the ROI values of the simulated "pure" image (with negligible FWHM) and those of the simulated and the measured PET images to correct for the PVE effect. By varying the ratio of radiotracer concentrations for different tissue components, the in-plane FWHM's of a three-dimensional point spread function, and the ROI size, the authors evaluated the performance of these two approaches in terms of their accuracy and sensitivity to different simulation configurations. The results showed that both approaches are more robust than the approach developed by Muller-Gartner et al. (1992), and the second approach is more accurate and more robust than the first. In conclusion, the authors recommend that the second approach should be used on FDG PET images to correct for partial volume effects and to determine whether an apparent change in GM radiotracer concentration is truly due to metabolic changes.
71 citations
TL;DR: In this paper, a modified Reynolds equation for solving the ultrathin film gas lubrication is proposed to overcome the complicated and time-consuming difficulties of solving the linearized Boltzmann equation.
Abstract: A new modified Reynolds equation for solving the ultrathin film gas lubrication is proposed to overcome the complicated and time-consuming difficulties of solving the linearized Boltzmann equation. The model equation is based on modified high-order slip-flow velocity distribution with three adjustable coefficients, which are corrected according to the Boltzmann model. The results are compared to those obtained using other kinds of currently employed modified Reynolds equations. It shows that the present model produces a closer approximation to that of the exact Boltzmann model than do other models, in a wider range of inverse Knudsen number. In addition, the newly derived equation is widely applicable to practical use.
68 citations
TL;DR: In this article, a series of cholesteric copolycarbonates of isosorbide were obtained which formed a broad cholesterolic phase with a Grandjean texture.
Abstract: (S)-((2-Methylbutyl)thio)hydroquinone was prepared from benzoquinone and (S)-2-methylbutyl mercaptan. One series of cholesteric copolycarbonates was prepared from this chiral hydroquinone, methylhydroquinone, and 4,4‘-dihydroxybiphenyl by interfacial polycondensation with diphosgene. All copolycarbonates were noncrystalline and decomposed upon heating above 250 °C. A Grandjean texture was only observed for one sample. A second series of cholesteric copolycarbonates was prepared from isosorbide, methylhydroquinone, and 4,4‘-dihydroxybiphenyl. Four different polycondensation methods were studied and compared in this case. The best results were obtained by polycondensation in pyridine containing organic cosolvents. Two copolycarbonates of isosorbide were obtained which formed a broad cholesteric phase with a Grandjean texture.
53 citations
TL;DR: In this paper, a new approach based on optimization theory is proposed to investigate the determination of locations and sizes of APLCs, and the objective is to minimize the new APLC injection currents and the voltage distortion while satisfying the harmonic standard.
Abstract: The APLC (active power line conditioner) is a type of active power filter that compensates voltage waveform distortion caused by harmonics in power systems. This paper presents a new approach, based on optimization theory, to investigate the determination of locations and sizes of APLCs. The objective is to minimize the new APLC injection currents and the voltage distortion while satisfying the harmonic standard. The test results for an 18-bus distribution system show the applicability of the proposed method.
51 citations
TL;DR: In this paper, activated carbons were prepared from three Australian bituminous coals and the preparation process consisted of carbonization followed by activation in CO sub 2 and the results reveal that the oxygen content of the coals has a great influence on the behavior during preparation and on the properties of the products.
Abstract: Activated carbons were prepared from three Australian bituminous coals in this study. The preparation process consisted of carbonization followed by activation in CO{sub 2}. Experimental results reveal that the oxygen content of the coals has a great influence on the behavior during preparation and on the properties of the products. The coal with a higher O/C atomic ratio has a lower peak temperature for volatile evolution during carbonization and is able to produce a char with a higher surface area. The reactivity in CO{sub 2}, the surface area, and the pore volume of the resulting activated carbon are all increasing functions of the O/C ratio of the coal precursors. An SEM study shows that at high burn-off levels a higher portion of gasification occurs at the exterior surface of the carbon from the coal with a lower O/C ratio, indicating that the diffusion resistance may be stronger for this carbon. For the same coal precursor, the average pore diameter of the activated carbon increases as the temperature for activation is increased in the range of 800--900 C.
TL;DR: In this article, a composite of tricalcium phosphate (TCP) ceramic particles and formaldehyde cross-linked gelatin, called GTF, was used for human myoblast cell culture.
TL;DR: In this article, the authors proposed a GA in conjunction with constraint handling techniques to solve the thermal unit commitment problem, where the difficult minimum up-and down-time constraints are embedded in the binary strings that are coded to represent the on-off states of the generating units.
TL;DR: In this paper, a configuration for realising sinusoidal oscillators using a single FTFN is proposed, where all the capacitors are grounded or virtually grounded, and four of the proposed oscillators enjoy independent oscillation control through a single passive element and independent frequency control through another single active element.
Abstract: A novel configuration for realising sinusoidal oscillators using a single FTFN is proposed. Experimental results of six oscillators verified the theoretical analyses. All the capacitors are grounded or virtually grounded. Four of the proposed oscillators enjoy independent oscillation control through a single passive element and independent frequency control through another single passive element.
TL;DR: In this article, the stability of the dithered nonlinear singularly perturbed multiple time-delay reduced-order model was analyzed by using the relaxed method to analyze stability when the frequency of dither is sufficient high.
Abstract: Dither is a high frequency signal injected into nonlinear systems for the purpose of improving their performance. Stability of the dithered nonlinear singularly perturbed multiple time-delay reduced-order model and by using the relaxed method to analyze stability of the dithered reduced-order model when the frequency of dither is sufficient high. Moreover, if the singular perturbation parameter is sufficiently small, then stability of the relaxed model would imply stability in finite time of the dithered nonlinear singularly perturbed multiple time-delay system.
TL;DR: In this article, four series of thermotropic polyurethane elastomers (TPUEs) were synthesized by using 4,4′-methylenedicyclohexyl diisocyanate (H12MDI) reacted with various mesogenic units, such as benzene-1,4-di(4-iminophenoxy-nhexanol), benzene -1, 4-di (4-IMINophenol), and 3,3′-(4, 4′-biphenylene)dipropanol, which
Abstract: Four series of thermotropic polyurethane elastomers (TPUEs) were synthesized in this study. The hard segments were formed by using 4,4′-methylenedicyclohexyl diisocyanate (H12MDI) reacted with various mesogenic units, such as benzene-1,4-di(4-iminophenoxy-n-hexanol), benzene-1,4-di(4-iminophenol), and 3,3′-(4,4′-biphenylene)dipropanol, which also acted as the chain extender. Poly(oxytetramethylene)glycols (PTMEGs), PTMEG-2000 (Mn 2,000) and PTMEG-1000 (Mn 1,000) were used as a soft segment. The structures of all synthesized thermotropic liquid crystalline polyurethanes (TLCPUs) were characterized by FTIR spectroscopy. The effects of mesogenic units on the LC properties and elastic behaviors of LCPUs were studied. It was difficult to show LC behaviors for the PU elastomers derived from the mesogenic units with a lower aspect ratio, such as 3,3′-(4,4′-biphenylene)dipropanol, or the long soft segments, PTMEG-2000. In addition, these PU elastomers show better elastic properties by using a higher aspect ratio mesogenic unit as the chain extender, such as benzene-1,4-di(4-iminophenoxy-n-hexanol and benzene-1,4-di(4-imino-phenol)). The thermal properties were investigated by DSC measurements, thermal optical polarized microscopy, wide angle X-ray diffraction, dynamic mechanical analysis, and thermogravimetric analysis. The mechanical properties were measured by a tensilemeter. © 1996 John Wiley & Sons, Inc.
TL;DR: In this article, the power-law exponents (n) obtained from dynamic measurements for determining the sol-gel transition point were between 0.62 and 0.69, indicating a percolation mechanism for the gelation process.
Abstract: The flow behavior of whey protein isolates (WPI) was studied in systems processed under different conditions. Experiments were undertaken to study effects of heating conditions (temperature/time), pH, solid content, calcium chloride, and guanidinium hydrochloride addition on the gelation of whey protein isolate solutions. The rheological data demonstrated a power-law frequency dependence of the viscoelastic functions G″ (ω) and G″ (ω) and a frequency-independent tan δ determined from a multi-frequency scan of tan δ vs gelling time at the gel point. The power-law exponents (n) obtained from these dynamic measurements for determining the sol-gel transition point were between 0.62 and 0.69. Those values suggest a percolation mechanism for the gelation process.
TL;DR: Non-porous silica with an average diameter of 1.4 μm was synthesized and derivatized for the high-performance affinity chromatography of proteins and the desorption rate constant and equilibrium association constant under elution conditions were found to have substantial effects on the elution time and the shape of theElution peak.
TL;DR: In this paper, the electron donor for yeast-mediated enantioselective bioreduction of acetophenone was ethanol and NADH was added externally to assist the reduction.
TL;DR: Experimental results show that this quick and efficient technique can determine the 3-D profile of an object with an accuracy of 0.5 mm.
Abstract: A quick and efficient technique for automatic profilometric measurement of a large-form part is proposed and verified by experi- ment. When a laser stripe is projected onto an object, the deformed laser line image is detected by a solid-state array camera and automatically transferred to its space position using a least-squares mapping algo- rithm. Measurements can be executed on any surface of a 3-D object except the base. Large arrays of data points are acquired on each sur- face by means of a scanning mechanism. Since the measuring data from each laser stripe position can provide 2-D information concerning the surface contour, the laser stripe and the solid-state array camera are integrated into a measurement system for obtaining the entire 3-D infor- mation. Experimental results show that this technique can determine the 3-D profile of an object with an accuracy of 0.5 mm. © 1996 Society of Photo-Optical Instrumentation Engineers.
TL;DR: In this article, a formulation of influence coefficient matrices is derived from the equations of motion for unsymmetrical rotors by using a complex co-ordinate representation and the finite element method.
TL;DR: The recent discovery of isotopes with Z = 110-111 is consistent with a monopole-monopole interaction that does not appear explicitly in Nilsson-Strutinsky mass systematics, and a competition between SU (2) and SU (3) dynamical symmetries as mentioned in this paper.
TL;DR: The elasticity of airway secretions plays an important role in airway reopening and is reported on the basis of studies on the influence of viscoelastic gels as lining fluids on the pressure-velocity relationships in an airway tube model.
Abstract: The influence of viscoelastic gels as lining fluids on the pressure-velocity relationships in an airway tube model (Gaver et al. J. Appl. Physiol. 69: 74-85, 1990) was examined. A flow instability was observed due to the occurrence of a sol-gel transition in the viscoelastic properties under flow conditions. We further report measurements of the viscoelastic properties of airway secretions. Airway secretions are gels under small strains and have a yield stress of 4-7 dyn/cm2. Secretions from the pharyngeal airway show lower elasticity than secretions from the trachea. The airway reopening process is simulated using a Weibel lung geometry by incorporating the constitutive equations from the model gel studies and utilizing the rheological data on airway secretions. In these simulations, a "popping-open" phenomenon arises from a flow instability in airway generations 8-14 when the rheological properties of the lining fluids are assumed to be similar to those of pharyngeal secretions. On the basis of these studies, the elasticity of airway secretions plays an important role in airway reopening.
TL;DR: In this paper, the dynamics of a simply supported viscoelastic beam, which is subjected to harmonic and parametric excitations simultaneously, is studied. And the stability of the system is analyzed using the Routh-Hurwitz criterion.
TL;DR: The complexes Mo2(OAc)Cl3(η3-tetraphos-2) and Mo2OAc2Cl2(PPh3)2 with tetra...
Abstract: The complexes Mo2(OAc)Cl3(η3-tetraphos-2) (tetraphos-2 = P(CH2CH2PPh2)3, 1, and Mo2(OAc)Cl3(η3-etp)(etp = Ph2PCH2CH2P(Ph)CH2CH2PPh2), 2, were prepared by reactions of Mo2(OAc)2Cl2(PPh3)2 with tetra...
TL;DR: The structure of broussoflavonol E (8,2′,6′-triprenyl-3,5,7,3′,4′-pentahydroxyflavone) has been revised to 8,5′, 6′-trianglomerate triprenyl (3, 5, 7, 3, 3.5, 4.4), from Formosan Broussonetia papyrifera as mentioned in this paper.
TL;DR: In this paper, the influence of bearing damping on the instability of rotating asymmetric shafts supported by isotropic bearings is investigated, and an analytical method based on modal expansion is developed to determine transition curves for stable and unstable regions.
23 Jun 1996
TL;DR: In this paper, an induction motor (IM) speed drive with the application of an extended Kalman filter (EKF) and a proposed recursive least square (RLS) estimator is introduced.
Abstract: An induction motor (IM) speed drive with the application of an extended Kalman filter (EKF) and a proposed recursive least square (RLS) estimator is introduced in this paper. The rotor resistance of the IM is identified by the EKF; and the rotor inertia constant, the damping constant, and the disturbed load torque of the IM are estimated by the proposed RLS estimator, which is composed of an RLS estimator and a torque observer. The integral proportional (IP) speed controller is designed on-line according to the estimated rotor parameters. Then the observed disturbance torque is fed forward to increase the robustness of the induction motor speed drive.
TL;DR: The primary conclusion was that the satchel with two shoulder straps and two pouches, which results in more symmetric loading than the other satchel, is the most desirable of the satchels tested.