Abstract:Focusing on whether fuzzy system can approximate any given function, the sufficient and necessary theory of one type of fuzzy systems as universal approximators was investigated. Mamdani fuzzy systems with product inference engine (PIE) and mean of maximum (MOM) defuzzificator can be classified two cases according to rule consequent: simple point rule consequent and fuzzy set rule consequent. Based on Weierstrass's first theorem and properties of membership functions, sufficient and necessary condition is proved respectively. A simulation example is given to show the effectiveness of the proposed method.

Abstract:This paper investigates the robust admissibility analysis and resilient filter controller synthesis for a class of discrete-time piecewise affine singular systems with asymptotic stability which possesses H∞ performance is considered in this paper, in order to eliminate the adverse effects of external disturbances and measurement noise of control system performance. By using the piecewise-affine singular Lyapunov functions combined with Projection lemma and some basic lemmas, an approach of designing robust H∞ feedback controller is given, the conclusions ensure resilient filtering error dynamic system possessing H∞ performance. It is shown that the controller gains can be obtained by solving a family of LMIs parameterized by scalar variables. The feedback controller gain and resilient filter system matrix can ensure the stability of systems and guarantee the H∞ performance of the piecewise-affine singular systems. Finally, the practicability of the proposed methodologies is confirmed via some simulation examples.

Abstract:A modal test method based on videogrammetric for large flexible structure on orbit is presented. The methods of 3D dynamic reconstruction, camera calibration and pixel extraction are described. A ground experiment is performed using a kind of antenna model and two fast cameras. Image data is acquired frame by frame during the free vibration period of the model, and vibration signals are obtained by a time series of images. The ERA method is applied to identify the modal parameters of the antenna model, and the experimental results show that the videogrammetric is a promising method for on-orbit vibration measurement which avoids the difficulty of installing accelerometers on the flexible structures.

Abstract:The fluid dynamics of the multiphase flow induced by water entry of high speed projectiles with various heads are different. Numerical simulation for modeling the high-speed water entry problem of projectiles with different heads at an initial impact velocity was performed. Finite Volume Method was introduced to solve the Reynolds Averaged Navier-Stokes equations, and the motion of the projectiles and cavity formation were obtained. The results showed that the cavity radius was related to the angle and the drag coefficient of the cone heads. The distribution of pressure coefficient on the cone and velocity around the shoulder of the projectiles were also obtained. During the initial stage of the water entry, there will be an extremely high pressure load. When the angle of the cone head is larger, the pressure gets higher, the pressure coefficient is larger, and the velocity of the water which is arranged by the projectile is higher.

Abstract:Face contour extracted by most existing extraction technology has the problem of non-smooth. Aimed at this situation,an segmentation modeling method for head-face contour is proposed. The piecewise function model is established using hyperelliptic curve,elliptic curve,circular curve and parabolic curve according to points definition and segmentation of contour. Contour sample's parameters obtained from the processing and optimization of 100 real human head-face images which contains five kinds of face verify the effectiveness and universality of the model. The result shows that the average error is under 1.2% and the maximum error is under 2.6% for each sample after optimizing the model. Finally the range of model parameters corresponding to each type of face is given by face shape classification based on the mathematical model.

Abstract:A micro-droplet printing deposition 3-axis motion platform was established to achieve efficient plane array package interconnect solder bumps jet printing. The platform and the multi-axis motion control system were developed based on LabVIEW, with the structure of “PC+ motion control card”. According to the coordinate data of the solder bumps, the jet printing movement path optimization was realized with ant colony algorithm, and the efficiency of movement was also improved effectively. A laser interferometer was used to measure the repeatability and positioning accuracy of the motion platform, and the results showed that the motion platform could meet the accuracy requirement of the BGA packaging technology.

Abstract:The road condition can be estimated by the extended state observer and the recursive least square method based on a 7DOF nonlinear vehicle model. in which the wheel force is analyzed, the force equilibrium equation is put forward and then the second order nonlinear extended state observer is designed. The results show that the extended state observer can achieve the observation of the utilization adhesion coefficient. Then a recurrence formula is derived based on the simplified tire model. The model shows the relationship between the utilization adhesion coefficient and the peak adhesion coefficient. The peak adhesion coefficient estimator is designed based on the recursive least square method, and the Matlab／Simulink simulation results show that the estimator can identify the peak adhesion coefficient quickly. The adhesion coefficient estimator can obtain the real-time estimation accurately.

Abstract:To know the sealing performance of an improved brush seal on turbine, the leakage flow characteristics and distribution on rotor surface, bristle pack free height and fence height were numerically analyzed by adopting a non-Darcian porous medium model. And a corresponding comparison between labyrinth seal and brush seal was performed. The analysis shows that at the same clearance and pressure ratio the flow fields in hybrid brush seal are more complex than that in labyrinth seal and the leakage rate of brush seal is significantly less than that of labyrinth seal, at the same structure and parameters the leakage rate increase with the rise in pressure ratio. More over, the axial static pressure and turbulent kinetic energy of rotor surface gradually decline with a ladder-like distribution from inlet to outlet, the racial static pressure of fence height tends to be constant values. The radial velocity and turbulent kinetic energy increase with the rise in pressure ratio. The lower parts of the bristle and the fence height have obvious effect on the leakage characteristics. The results provide theoretical basis for the design of brush seal structure and the improvement of performance.

Abstract:To investigate the application of supercritical carbonation technology on cement-based material modification, and to study the effects of supercritical carbonation on microscopic and macroscopic properties of cement-based materials, in this paper, the supercritical carbonation tests have been done to study the change of carbonation depth, strength, pore structure and carbon dioxide absorption of the cement paste, mortar and concrete. It is shown that supercritical carbonation is a powerful tool to achieve the fast carbonation, improve the pore structure, enhance the strength and leach resistance of the material, and absorb a large number of CO₂, which is significant meaningful for optimizing the hazard waste cement solidify and the environmental protection.

Abstract:In the paper, Bellman-Ford algorithm with fixed order is modified in order to solve the shortest path problem with not more than k edges. After the k-th iteration, each path must own no more than k edges by modifying the labeling process of the origin algorithm. The modified algorithm proves true and its worst-case complexity is O(km). In contrast to the modified Bellman-Ford algorithm with FIFO order, experiments show that the algorithm has the significant competitive advantage in the large-scale case.

Abstract:To get the objective quality weight values for the alternates of each product, first, the product design is formulated as a product and／or tree model. Next, based on this model, a QFD and AHP combined multiple dimensional evaluation model for product quality is proposed. In the evaluation model, the customer requirements are transformed into the quality criteria of each level of a product by QFD and the quality of the alternates for each level of a product is evaluated by AHP, then their results are combined to compute the quality weight values for the alternatives of each level of a product. Finally, the evaluation model is demonstrated by a simulated example.

Abstract:To find the reason of limiting hole fracture and over-expected vibration amplitude on the mechanical environmental test to a Close Cable Loop(CCL) under only single-axial inner-plane swept frequency excitation, the finite segment method of multi-body dynamics was introduced to model and simulate the cable system with a concentrated mass and a position limiting hole, the cable vibration response and the contact force in limiting hole were obtained. The results showed that the vibration response started from inner-plane vibration to outer-plane vibration and to continuous rotational vibration. Cable vibration amplitude enhanced continuously due to rotational vibration process, and attenuated suddenly. The response process and vibration amplitude was coincided with the test. Continuous rotational vibration under swept frequency excitation is the key reason for the problem of fractures.

Abstract:To suppress noise of image more efficiently and further improve image visual effects, a noise suppression method of image based on shearlet transform and kernel anisotropic diffusion is proposed. Firstly, a noisy image is decomposed by nonsubsampled shearlet transform(NSST). Then the obtained low-frequency component and high-frequency components are processed by improved total variation (ITV) diffusion and kernel anisotropic diffusion (KAD), respectively. Finally, the noise suppressed image is obtained by synthesizing diffused low-frequency component and high-frequency components through inverse nonsubsampled shearlet transform(INSST). Experimental results are given, in terms of subjective visual effect and two quantitative evaluation indicators such as peak signal to noise ratio (PSNR), structural similarity (SSIM), a comparison is made with three recent proposed noise suppression methods based on wavelet threshold shrinkage and TV, based on nonlinear diffusion in complex contourlet domain, and using TV with adaptive shearlet domain restraint. A large number of experimental results show that the proposed method has stronger noise suppression ability and preserves edge and detail information more completely.

Abstract:To study the variation of the damp coefficients of a slender body during water exit, the vibration theory of an elastic body and the potential flow theory of fluid are adopted. For viscous damp coefficient, vortex induced vibration (VIV) model is introduced and the lift and drag forces are included in the structure vibration equation. The increment of damp coefficient by VIV is therefore obtained. For wave-making damp coefficient, time-domain Green Function is adopted. The problem of a sphere oscillating on the free surface is calculated first and compared with the published paper, and the results agree well with each other, which validates the numerical model and procedure in this paper. Based on this, the wave-making damp coefficient of a slender body under different vibration frequencies and different lengths during water exit are calculated and analyzed. The results show that the increment of damp coefficient by VIV rises with the increase of current, wave and the reduction of cavitation, while the wave-making damp coefficient is closely related to the length of water exit, the natural vibration mode and the vibration frequency of the slender body. For the case studied in this paper, the wave-making damp coefficient peaks when the head of the body comes out of the water and the vibration frequency is around 0.5 Hz, and the wave-making damp coefficient induced by the first and second order elastic vibration respectively is quite small, which can be neglected in the engineering application.

Abstract:To optimize load correction coefficient, based on press straightening control strategy with multi-step three-point bending process, two methods of least squares curve fitting and equivalent bending deformation energy were proposed. The simulation results of the Longitudinally Submerged Arc Welding(LSAW) pipe show that the optimum load correction coefficient calculated by least squares curve fitting method is bigger than normal. This is due to that, when the actual loading moment is greater than the theoretical straightening moment, the impact on the pipes is greater. However, the optimum load correction coefficient calculated by the equivalent bending deformation energy method, is more applicable, which is verified by the straightening physical simulation experiments of small sized pipes with different geometries, initial deflection distribution and straightening step. The straightness of the pipes with their initial straightness of 4‰~10‰ can be improved within 1.1‰. Thus, this method provides a convenient way to carry out the press straightening control strategy with multi-step three-point bending process.

Abstract:In order to prevent high error floor of classic Turbo at middle and high SNRs, a modified Turbo codes, named as 3D-Turbo codes, is proposed in which some of the parity bits from the classical encoders are further encoded by a rate-1 post encoder. The encoder structure of 3D-Turbo Codes is introduced and analysis of main factors affecting performance is provided, then the iterative decoding process and detailed derivation of the Max-Log-Map algorithm of 3D-Turbo Codes is presented, performance based on 3GPP2 standards is simulated. The theoretical analysis and results show that 3D-Turbo Codes have lower error floor compared to 3GPP2 Turbo Codes, at the expense of a very small increase in complexity. Therefore, under middle or high SNRs and strict BER requirement, 3D-Turbo Codes are expected to have extensive application prospects.

Abstract:The traditional interacting multiple model (IMM) algorithm usually models the mode evolutions as Markov processes with constant mode transition matrix and leaves the correlative information among sub-filters out. However, because of the complexity of the practical application, the traditional IMM algorithm is unsuitable in aircraft tracking. To solve these problems, an optimal mode transition matrix IMM algorithm（OMTM-IMM）is presented. The new algorithm uses the linear minimum variance theory to calculate the optimal mode transition matrix according to the correlations between sub-filters. In this case, the new matrix further approaches the truth one, and the estimation accuracy can be improved. This conclusion can be support by the following theoretical derivation and simulations in aircraft tracking.

Abstract:To overcome the tracking control problem for a class of strict-feedback nonlinear system with model uncertain, an adaptive fuzzy backstepping predication control algorithm which can make the closed-loop system stable and minimize the receding horizon guaranteed cost on-line is proposed. Fuzzy logic systems are employed to approximate the unknown term in the design process. As the adaptive parameter are directly used to estimate the norm of the optimal approximation weight vector, only one parameter need to be tuned on-line. Considering the property of the fuzzy basis function, the designed control laws and adaptive laws do not contain the fuzzy basis function term. Theoretically, it is proved that the using the constructed controller can guarantee that all signals in closed-loop are semi-globally uniformly ultimately bounded, and the tracking error convergence to a small neighborhood of the origin. As the form of the controller designed in this way is simplicity and the computation is small, this control strategy is easily realized in practice. Finally, the simulation results demonstrate the feasibility of the proposed scheme.

Abstract:Aiming at the problems of low performance matching, more mismatching pairwise, and low registration precision, which are the characteristic of traditional SAR image registration methods, we propose a novel and efficient local invariant feature-based algorithm. First, the feature points are detected by features from accelerated segment test(FAST) method and described by DAISY descriptor in SAR image. Second, Kd-tree-based dual-matching strategy and random sample consensus (RANSAC) are used to establish fine feature matching. Third, affine transform model is estimated for image resampling and transformation, and rough registration is implemented. Finally, feedback mechanism is constituted for fine registration based on the estimation of registration precision. The flexibility and efficiency is demonstrated by experiments with slant range SAR images acquired from different working model, different times, viewpoints, wavelengths and polarizations.

Abstract:To solve the problem that the spectrum allocation algorithm based on graph theory coloring algorithm has not fully considered the actual bandwidth needs of users, this paper proposes a spectrum allocation based on user priority algorithm improved CSGC and the original algorithm. The algorithm introduces two time factors that are respectively called idle spectrum and user demand, by setting the user priority, the function can meet the needs of users during the second spectrum allocation. Simulation results show that the algorithm not only retains the performance of the original algorithm CSGC, but also greatly improves the spectrum utilization.

Abstract:To promote the defective craft in non-circular grinding NC system, a special NC system for non-circular grinding is presented based on CPAC. First, on the basis of piecewise cubic spline fitting as mathematical foundation, the cutter center coordinates of X-Y is calculated. Second, the importance of constant speed grinding is produced, and two algorithms based on constant length of arc interpolation are put forward to realize constant speed grinding. Third, the method of error measuring and compensation is given. Finally, integrated system is completed and applied to three-axis milling machine. The experiment proves that the system can meet the needs of non-circular grinding.