Showing papers by "Southeast University published in 1990"
TL;DR: An unbiased identification algorithm for jointly estimating the time delay and system parameters can be obtained based on correlation analysis by applying a new modified least-squares estimation method to eliminating the bias in the system parameters estimates arising from colored noise.
60 citations
01 Apr 1990
TL;DR: It is proved that the symmetric exponential filter is the optimal edge detection filter in the criteria of the signal to noise ratio, localization precision and unique maximum.
Abstract: In this paper, we give a new demonstration in which it is proved that the symmetric exponential filter is the optimal edge detection filter in the criteria of the signal to noise ratio, localization precision and unique maximum. Then we deduce the first and the second directional derivative operators for symmetric Exponential Filter and realize them by first order recursive algorithm, and propose to detect the edges by maxima of Gradient (GEF), or by the zeros crossing of Second directional Derivative along the gradient direction (SDEF).
38 citations
TL;DR: Several new training algorithms with very fast convergence are presented, which use derivative information to efficiently estimate the optimal descent factors, thus providing the fastest descent of the mean squared error in the descent directions that characterise the algorithms.
Abstract: Poor convergence of existing training algorithms prevents wide applications of backpropagation neural networks. Several new training algorithms with very fast convergence are presented. They all use derivative information to efficiently estimate the optimal descent factors, thus providing the fastest descent of the mean squared error in the descent directions that characterise the algorithms. Simulation results are illustrated.
22 citations
TL;DR: This paper gives some amendments to the fuzzy operator used in references of a double model based on fuzzy synthetic decision and multicriteria decision that has been used successfully to make a quantitative evaluation of the teaching quality of some courses in the author's university.
20 citations
TL;DR: In this article, the deposition of Ta 2 O 5 thin films by dc magnetron reactive sputtering in a pure O 2 atmosphere was described, and the properties of the obtained film were investigated by AES, XPS, RBS, XRD and C-V characteristic measurements.
19 citations
TL;DR: In this article, two kinds of broadside coplanar waveguide antenna arrays are proposed and their performances are confirmed by experiments at a frequency of about 375 GHz and they have completely printed structures and can be used in CPW MIC/MMIC operating up to millimetre wave frequencies.
Abstract: Two kinds of new broadside coplanar waveguide (CPW) antenna arrays are proposed and their performances are confirmed by experiments at a frequency of about 375 GHz They have completely printed structures and can be used in CPW MIC/MMIC operating up to millimetre wave frequencies The array element spacings are appropriate and grating lobes are effectively prevented
18 citations
01 Nov 1990
TL;DR: A three-dimensional edge operator for detecting anatomical structures in medical imaging that uses the spatial moments of the gray-level surface, and operates in three dimensions with any window size is presented.
Abstract: A three-dimensional edge operator for detecting anatomical structures in medical imaging is presented. It uses the spatial moments of the gray-level surface, and operates in three dimensions with any window size. It allows the location and the contrast surface, as well as the surface orientation, to be estimated. The computation of the discrete version is reported. Bias and errors due to the spatial sampling and noise are analyzed at both a theoretical and experimental level. The moment-based operator is compared with other well-known edge operators using simple shaped primitives for which the analytical solution is known. The 3-D rendering of real data is then provided by merging the operator in a ray-tracing framework.<>
17 citations
14 citations
TL;DR: In the abovementioned correspondence P. Yip and K.R. Rao presented a shift property for even discrete cosine transforms and sine transforms, and the commenter points out that the odd counterparts (ODCT and ODST) also exist in the family.
Abstract: In the abovementioned correspondence P. Yip and K.R. Rao (see ibid., vol.ASSP-35, p.404-6, Mar.1987) presented a shift property for even discrete cosine transforms (EDCT) and sine transforms (EDST). The commenter points out that the odd counterparts (ODCT and ODST) also exist in the family. He extends Yip and Rao's results to these odd triangular transforms and makes several corrections to their work. >
13 citations
TL;DR: A relationship between bonding strength and bonding area has been found which suggests that the increase in bonding strength is caused by the bonding area increase in the oxidised silicon wafer direct bonding (SDB) process as discussed by the authors.
Abstract: A relationship between bonding strength and bonding area has been found which suggests that the increase in bonding strength is caused by the bonding area increase in the oxidised silicon wafer direct bonding (SDB) process. The bonding area shows a saturation property with bonding time. Diffusion of various species existing in bonding interface region plays a key role in SDB process over different temperature. Viscous flow of the oxides completes bonding at T > 1050°C. A rapid thermal bonding (RTB) at 1200°C for 2min following 800°C for 2hr annealing realises complete bonding with little doping profile change in the system.
13 citations
TL;DR: In this paper, the authors extended the method of lines (MOL) for cylindrical co-ordinate systems and analyzed the dispersion characteristics of the microstrip line using this method.
Abstract: The method of lines (MOL) is extended for use in cylindrical co-ordinate systems and the dispersion characteristics of the cylindrical microstrip line are analysed using this method. Numerical results are presented and compared with previously published data.
08 May 1990
TL;DR: In this paper, a novel model of a Gunn diode VCO (voltage-controlled oscillator) is established on the basis of the computation of coupling disk capacitance between a diode and a varactor using spectral-domain Hankel transformation.
Abstract: A novel model of a Gunn diode VCO (voltage-controlled oscillator) is established on the basis of the computation of coupling disk capacitance between a Gunn diode and a varactor using spectral-domain Hankel transformation. The nonlinear analysis of the Gunn diode VCO is carried out by using the harmonic balance technique. The experimental results are compared with the computed results. It is shown that the developed model and analysis program are effective. A special optimization procedure for finding the doping power factor of a varactor is proposed in order to get optimal tuning linearity. >
01 May 1990
TL;DR: Simulation results show that CVQ-TA can give a good visual perceptual quality and can be applied for large block size (8*8 or 16*16), which is more efficient for block coding.
Abstract: A new VQ-based image coding method, classified vector quantization using texture analysis (CVQ-TA) is proposed. The most notable differences between CVQ-TA and CVQ are: (1) the classification in CVQ-TA operates in the transform domain by means of texture analysis, and (2) product-code vector quantization is used to reduce the complexity increasing with the subblock size. Because of these characteristics, CVQ-TA can be applied for large block size (8*8 or 16*16), which is more efficient for block coding. Simulation results show that CVQ-TA can give a good visual perceptual quality. >
01 May 1990
TL;DR: A multilayer back-propagation neural-network model which performs Chinese speech synthesis with high speed quality is described and the speech with unlimited vocabulary is produced by the rules.
Abstract: A multilayer back-propagation neural-network model which performs Chinese speech synthesis with high speed quality is described. The following are detailed: (1) the basic properties of the neural network and its difference from the traditional methods for speech processing; (2) selection of basic acoustic units which can be concatenated to generate utterances; (3) selection of the formant parameters; and (4) hybrid formant synthesizer and its neural network architecture. The test written in Chinese phonetic symbols (Chinese pingyin) is conveyed into the system and the speech with unlimited vocabulary is produced by the rules. >
TL;DR: In this article, an efficient numerical approach is presented for the analysis of cladding-network interaction in pretensioned cable roof structures under static loads, based on the subregion mixed energy principle, which allows for the linear and non-linear aspects of the behaviour of the structure to be treated separately.
03 Apr 1990
TL;DR: A multilayer neural network used for nonlinear predictive image coding gives a better performance than linear predictive coding and has not only the ability to generalize but also noise reduction capabilities.
Abstract: A multilayer neural network used for nonlinear predictive image coding is described. Two coding schemes, nonadaptive and adaptive, are shown. Owing to matching of the local properties of the image, nonlinear predictive coding gives a better performance than linear predictive coding. A series of computer experiments shows the method has not only the ability to generalize but also noise reduction capabilities. Compared with differential pulse code modulation (DPCM), it greatly reduces the number of bits to be transmitted. >
TL;DR: In this paper, it is suggested that a high-order linear system can be approximated by a low-order model with a time delay based on the proposed mixed method, which gives rise to the desired Stability of the model produced.
Abstract: A novel approach to the simplification of dynamic systems is introduced. It is suggested that a high-order linear system can be approximated by a low-order model with a time delay based on the proposed mixed method. The denominator of the reduced model is determined by the Routh stability method, which gives rise to the desired Stability of the model produced. The numerator parameters are then estimated by using identification techniques and the time delay is chosen optimally according to an output-errors criterion. It is shown that the reduced-order time-delay model produces a good enough approximation compared with models obtained from other methods. The reduction procedure is fully computer oriented. The performance of the new approach is verified by the application of numerical examples.
01 May 1990
TL;DR: In this paper, an efficient method for designing two-dimensional (2D) recursive fan filters is presented, which results in a great reduction in the required multiplications and in the simplified realization structure composed of all-pass filters as compared with the published design procedures.
Abstract: A very efficient method for designing two-dimensional (2-D) recursive fan filters is presented. The odd-ordered analog elliptical filter is used as a 1-D prototype to synthesize the complementary quadrant fan filters, as well as 90 degrees fan filters, by means of an index transformation. The algorithm results in a great reduction in the required multiplications and in the simplified realization structure composed of all-pass filters as compared with the published design procedures. The design of zero-phase fan filters is also discussed. Only N-1 and 2(N-1) multiplications are needed to implement non-zero- and zero-phase complementary fan filters, respectively, if an Nth-order 1-D prototype elliptical filter is adopted. >
TL;DR: In this article, a new process which permits the electrostatic bonding of GaAs to glass is presented, where the hydrogen plasma treatment of the GaAs and glass is employed prior to the bonding.
Abstract: This paper presents a new process which permits the electrostatic bonding of GaAs to glass. The hydrogen plasma treatment of GaAs and glass is employed prior to the bonding. Auger electron spectroscopy (AES) has been used to study the properties of GaAs and glass before and after plasma treatment. Scanning electron microscopy (SEM) has been performed to view the interface cross-section image of the bonded GaAs/ glass. It is shown that the hydrogen plasma treatment appears to be effective in the electrostatic bonding of GaAs to glass.
TL;DR: In this paper, a transverse resonance method for analyzing rectangular T-septum waveguides is described, based on a simple equivalent circuit model, and the cutoff wavelength and bandwidth characteristics are compared with available values in the literature.
Abstract: A transverse resonance method for analysing rectangular T-septum waveguides is described. This method is based on a simple equivalent circuit model. Numerical results for cutoff wavelength and bandwidth characteristics are compared with available values in the literature.
TL;DR: In this article, a new method for analyzing groove guides with grooves of arbitrary cross-section is presented, which is based on the combination of a transverse resonance method and a numerical integral Numerical calculations for V-groove guides verified the validity of this approach.
Abstract: In the letter a new method for analysing groove guides with grooves of arbitrary cross-section is presented This method is based on the combination of a transverse resonance method and a numerical integral Numerical calculations for V-groove guides verified the validity of this approach Theoretical results for cutoff wavelengths of groove guides with circular and trapezoid-grooves are also presented
TL;DR: In this paper, the formation and growth of solid particles of Sn-15% Pb and Al-40% Zn were studied using a Couette type viscometer in isothermally and continuously cooled shear flows.
Abstract: Formation and growth of solid particles of Sn-15% Pb and Al-40% Zn were studied using a Couette type viscometer in isothermally and continuously cooled shear flows. Solid particles come mainly from broken dendrites in the initial stage of solidification. With increase of solid fraction, solids grow in an equiaxial and merging way in the flow of the partially solidified alloy. Mergence happens between two particles of small misorientation, and merging growth is performed by the growth of protruding parts on the solid-liquid interfaces of the solids.
TL;DR: In this article, a new mechanical model and closed form form formulae for analyzing a rectangular vessel with short axial length are proposed. But the results from the new model are in agreement with those from the ASME Code formulAE.
01 Jan 1990
TL;DR: In this article, a new method for suppressing highfrequency chattering of sliding controller in variable structure system is presented, where a proper zone for switching control is definded in the vicinity of ordinary switching hyperplane.
Abstract: High-frequency chattering of sliding controller in variable structure system is undesirable in practice. A new method for suppressing chattering is presented in this paper. A proper zone for switching control is definded in the vicinity of ordinary switching hyperplane. This switching zone shrinks to the origin as the state variable converges to zero. The switching function is modified by certain integral transformation. Sustained oscillation is avoided and the global asymptotic stability is guaranteed. Simulations confirm the theoretical analysis.
01 May 1990
TL;DR: An algorithm is presented for the resolution of an unknown number of closely spaced, overlapping, and noisy echoes of a signal of unknown shape.
Abstract: An algorithm is presented for the resolution of an unknown number of closely spaced, overlapping, and noisy echoes of a signal of unknown shape. No assumption is made about the signal (or its spectrum). Simulation results demonstrate that the algorithm is effective. >
TL;DR: Using the basis of the variational principle, a method to control numerical solution wiggles of the diffusion-drift equation is proposed in this paper, which coincides with the S-G and SUPG methods in special cases.
Abstract: Using the basis of the variational principle, a method to control numerical solution wiggles of the diffusion-drift equation is proposed, which coincides with the S-G and SUPG methods in special cases.
TL;DR: In this paper, an accurate hybrid-mode analysis of suspended striplines with finite metallisation thickness and substrate supporting grooves is presented, with particular attention paid to the calculation of the characteristic impedance.
Abstract: This letter presents an accurate hybrid-mode analysis of suspended striplines with finite metallisation thickness and substrate supporting grooves. Particular attention is paid to the calculation of the characteristic impedance. The significant effects of finite metallisation thickness and substrate supporting grooves on the transmission characteristics of suspended striplines are revealed in the higher frequency range.
TL;DR: A polygon discretization technique for establishing a network model suitable for both TEM transmission lines and hollow waveguides is introduced and the network model decomposition algorithm, or diakoptic algorithm, is presented for solving the transmission-line problems.
Abstract: A polygon discretization technique for establishing a network model suitable for both TEM (transverse electromagnetic) transmission lines and hollow waveguides is introduced. A network model decomposition algorithm, or diakoptic algorithm, is also presented for solving the transmission-line problems and is shown to be useful when a computer is not sufficiently large to accommodate a problem. The network model decomposition algorithm can be used to calculate the characteristic impedance of an arbitrarily shaped TEM transmission line and the cutoff wavenumbers of a hollow waveguide of arbitrary section. Numerical results are also presented as a demonstration of the method's validity. >
TL;DR: By means of linearized Holstein-Primakofferer transformation and Green function theory, the spin wave dispersion curves are obtained for superlattices consisting of two kinds of Heisenberg antiferromagnetic layers.
Abstract: By means of linearized Holstein-Primakoff transformation and Green function theory, the spin wave dispersion curves are obtained for superlattices consisting of two kinds of Heisenberg antiferromagnetic layers It is interesting that the results are different in cases that a super-cell contains odd or even number of atomic planes, implying differences in physical properties
TL;DR: In this article, an accurate hybrid mode analysis of microstrip lines on the finite width substrate or near a substrate edge including finite metallisation thickness is described, and an approach for avoiding the calculation of higher modes in a rectangular waveguide partially filled with a dielectric is introduced.
Abstract: An accurate hybrid mode analysis of microstrip lines on the finite width substrate or near a substrate edge including finite metallisation thickness is described. The frequency dependent solutions for the transmission characteristics of the microstrip lines are presented. An approach for avoiding the calculation of higher modes in a rectangular waveguide partially filled with a dielectric is also introduced. The results provide useful information for the design of high packing density millimetre wave MMICs.