Showing papers by "Shanghai Jiao Tong University published in 1984"
TL;DR: It is proposed to use a logarithmic nonlinearity, followed by a linear minimum mean-square error estimator, which maps the myoelectric signal into an additive control signal-plus-noise domain in which the Kalman filter is employed to estimate the control signal.
Abstract: Proportional myoelectric control of powered prostheses requires the estimation of a time-varying control signal from the patient's myoelectric signal. Since the myoelectric signal is a zero-mean stochastic process, a nonlinearity is a necessary element of the estimator. Typically, a full-wave rectifier is used for this nonlinearity, followed by a low-pass filter to complete the estimation of the control signal. In this work, it is proposed to use a logarithmic nonlinearity, followed by a linear minimum mean-square error estimator. The logarithmic nonlinearity maps the myoelectric signal into an additive control signal-plus-noise domain in which the Kalman filter is employed to estimate the control signal. The theoretical performance of this estimator is obtained and verified by experiments.
42 citations
TL;DR: In this paper, an approximate approach for evaluation of the critical driving force is briefly introduced, i.e. ΔGα→M = 2.1 δ + 900 J mol−1, where δ is the yield strength of parent phase and 900 is the stored energy.
42 citations
TL;DR: In this article, the total driving forces for transformation and growth for the several possible mechanisms of the bainitic transformation in Fe-C alloys, i.e. γ → α + γ 1, γ→ α + Fe 3 C, and γ↵ → α'(the same composition), were calculated.
29 citations
TL;DR: In this paper, the secondary creep rate and rupture life of the nickel-base superalloy GH37 were determined at 700 and 850 °C under stresses of 471 and 196 MN m −2, and the influence of the hot corrosion due to a 75wt.% Na 2 SO 4 -25.%NaCl coating on the creep strength of the alloy was evaluated.
13 citations
TL;DR: To obtain a much tighter bound, a simple heuristic method is suggested instead of solving a linear programming problem and the flexibility dealing with some tests is discussed and it is helpful to the algorithm.
13 citations
TL;DR: In this article, a new theorem for determining definiteness of sign of functions is presented, which is applied to the stability of permanent rotations of a rigid body about a fixed point in five cases.
Abstract: A new theorem for determining the definiteness of sign of functions is presented. As the examples illustrate, it is applied to the stability of permanent rotations of a rigid body about a fixed point in five cases.
9 citations
TL;DR: In this paper, a structural inhomogeneity in bulk specimens resulting from ordering in austenite quenched around 800°C was found by TEM, and it is confirmed that ordering does occur in the Fe-Ni alloys studied and that ordering of the Austenite markedly affects Ms (Mb).
6 citations
01 Apr 1984-Graphical Models \/graphical Models and Image Processing \/computer Vision, Graphics, and Image Processing
TL;DR: The histogram pi is changed by an order-preserving and layer-preservative gray level transform which has layers at the optimum quantization levels which may be a simpler and more effective way of histogram modification.
Abstract: Digital image histogram modification using a discrete raster and quantized gray levels is described. The histogram of an original picture is labeled pi and is first processed toward an aim histogram p′j. The gray level transformation and resulting histogram qk′ can be decided by Eqs. (2) and (3). The effect of histogram modification is explained by a theorem. In accordance with the visual character of the eyes, an appropriate aim histogram p′j is selected. If pi is constant, p′j may be represented by a beta distribution which can be varied by altering the parameters α and β. The optimum quantization gray levels for different visual models are determined. The histogram pi is changed by an order-preserving and layer-preserving gray level transform which has layers at the optimum quantization levels. This may be a simpler and more effective way of histogram modification. Finally, the concept of apparent entropy of an image is introduced and an approximation method of calculation of apparent entropy is suggested.
5 citations
01 Mar 1984
TL;DR: The modified median filter and the gradient-median filter are proposed and the results show that these filters have the better performances than the pure median filter.
Abstract: The spiky noise reduction with preserving the useful information is an important subject in the image processing. The median filter is considered to be a good filter, but it also has some shortcomings. In order to overcome these shortcomings, the modified median filter and the gradient-median filter are proposed. The results of the experiments show that these filters have the better performances than the pure median filter.
3 citations
3 citations
TL;DR: In this article, the conditions for disturbance resistibility of singularly perturbed linear systems with low-frequency and high-frequency modes by state feedback are given, and the decomposition of the low-and highfrequency modes and the nonsingular transformation of coordinates are employed to show that the disturbance resistance of the slow and fast subsystems by state-feedback can ensure that the effect of disturbance on the output of the original system is O(∊).
21 Aug 1984
TL;DR: In this paper, a methode analytique par l'analyse des contraintes des joints tubulaires de type TYK is presented, which calcule the distribution of contraints and le facteur de concentration des contraints.
Abstract: On presente une methode analytique par l'analyse des contraintes des joints tubulaires de type TYK. On calcule la distribution des contraintes et le facteur de concentration des contraintes. Les resultats numeriques sont en bon accord avec les resultats experimentaux