Based the current state of domestic hardware resource, a scheme of regenerative braking system with the function of active pressurization simulation was proposed with the premise of ensuring braking feeling. Based on the control process of components of the proposed regenerative braking system combined with the ultimate flow requirement and p-V characteristics of the wheel cylinder, the design of the simulator structure was completed. Besides, the function of the system was verified on the experimental bench, which was set up with the application of xPC. The results show that the regenerative braking system with pressurization simulator can satisfy the requirement of braking and recover the braking energy effectively with the premise of ensuring braking feeling.

In order to meet the requirements of variable road conditions for vehicle traction control system, a road identification algorithm was proposed based on combined longitudinal and lateral brushed tire model. First, the tire-road forces were estimated by the Kalman filtering method; the road friction coefficient on each wheel was estimated using least square method, and its optimal slip ratio was obtained subsequently. Then, a fuzzy sliding mode based on traction controller was designed using the identified road information. Finally, the algorithm was verified using Matlab/Simulink and CarSim co-simulation. Results show that the proposed algorithm can identify the variation of road conditions and regulate the slip ratios of the driving wheels quickly and accurately, thus, the vehicle driving pe4rformance can be effectively improved.

A co-simulation platform of Electric Power Steering (EPS) system and vehicle model is built using CarSim and Simulink. Three levels of EPS parameters for sensitivity analysis are defined and their actual ranges are given according to vehicle measurement and debugging experience. The sensitivity analysis of the EPS parameters and two evaluation indices for steering performance is conducted on Isight software by employing orthogonal test and extreme difference analysis method. Meanwhile, using dynamic analysis the interaction relationship among these parameters and indices investigated. Then, the vehicle tests are conducted on the test platform of EPS vehicle under three levels of EPS parameters. Results indicate that the conclusions of sensitivity analysis conform to the response characteristics of the EPS vehicle. The results may provide guidance to debug and calibrate the parameters of EPS.

For the proposed electro-hydraulic brake system based on an integrated master cylinder, the pedal force transmission paths were analyzed under normal and failure operation modes. The pedal feeling and its influence factors were investigated. A pedal feeling simulator was designed with cluster springs, and simplified models under different operation modes were established using AMESim. The parameters, such as the piston damping coefficient, which affect the pedal force-stroke curve, the pedal rod return spring preload force, solenoid valve flow area and booster ratio, were studied by simulation. Bench test results show that the brake pedal characteristics could meet the design requirements, and the pedal force-stroke hysteresis losses are 11.5% for normal mode and 15.3% for failure mode, respectively.

To design the braking torque graded permanent magnet retarder, the rules of the factors that influence the braking torque retarder must be understood. In this paper, the mathematical model of the air-gap of magnetic field was established by means of analytic method. Using variable separation method and boundary conditions, the analytical expression of the magnetic induction intensity of the air-gap was obtained. According to the source and field theory, the computation model of braking torque, applicable to engineering application, was derived. The impacts of the number of magnetic pole pairs, the perimetric width and axial length of the permanent magnet, and the air-gap on the magnetic induction intensity and on the braking torque were analyzed based on the computation model. Based on the four parameters, four types of graded braking torque structures of the permanent magnet retarder were designed.

A qualitative and quantitative reliability assessment method based on the matter-element model was proposed for high-speed railway drivetrain. The failure accumulative damage theory and the rain-flow counting method were employed to build the matter-element model. The Analytic Hierarchy Process (APH) method was used to calculate the weight of each component in the high-speed railway drivetrain. According to the correlation function, the reliability rating of the tested drivetrain can be quantitatively estimated. Taking a certain type of high-speed railway drivetrain as an example, its reliability is rated to be level I by the presented method, and the most severe damage occurs on the transmission shaft, which is the main cause of the failure of the transmission system.

Sound pressure and sound intensity methods were used to measure the Transmission Loss (TL) of silent floor of high-speed train. Results of the two methods are in good agreement that the difference is within a reasonable range of engineering error, which avoid experiment muff. The results also provide certain reliability for subsequent simulation verification. It is shown that the sound insulation effect of silent floor is better than that of general floor. The damping loss factor was measured by pulse attenuation method, which was then used to calculate the TL using FE-SEA hybrid method. The calculation results of TL are in good agreement with the experiment results. Better sound insulation structure can be obtained by adjusting the thickness of plywood and the rubber layer. It is shown that when the thickness of the rubber layer is 2 mm and three layers of plywood have different thickness of 3 mm, 5 mm and 7 mm respectively, the silent floor has better sound insulation performance. The sound insulation performance of the silent floor can be optimized by improving the floor structure and the sound package, to establish the users' database.

In order to further improve the prediction accuracy of short-term traffic parameters, according to the inherent correlation between traffic parameters, on the basis of stationarity test and cointegration test for traffic parameters time series, a multivariate time series model for short-term traffic parameters forecasting is proposed, which is called vector error correction model. The stationarity of the vector error correction model was tested. Validation and comparative analysis were carried out using inductive loop data measured from the north-south viaduct in Shanghai, China. The experiment results indicate that the proposed vector error correction model has good prediction performance and can further reduce the prediction errors of short-term traffic parameters.

To optimally allocate the time and space resources for two adjacent intersections with coordinated signals and short left-turn lanes on the common section of a road, an optimization model was presented to jointly obtain the signal cycle length and green slit for each intersection. The objectives are to maximize the passing capacity of the entire intersection and minimize the total delay of vehicles. The decision variables of the model are the length of each short left-turn lane and the effective green time per phase. A case was designed to verify the effectiveness of the proposed model. First, two signal timing plans for each intersection were obtained using the proposed model and Webster model, respectively. Then, the offset between coordinated phases was calculated by a known method. Finally, the traffic operations under the two signal timing scenarios were simulated using VISSIM software. The outcomes show that the unit delay is decreased by 30% and the vehicle throughput is slightly increased for each intersection under the optimization scenario.

In order to accurately evaluate the traffic condition, based on the classical model combined with multi-source traffic detection data, a new queue length estimation method for signalized intersections was proposed. The data measured in an intersection in downtown Shanghai were used to verify the proposed method. The accuracy and effectiveness of this method under different conditions were analyzed. Results show that the accuracy of proposed queue length estimation method for signalized intersection is higher than classical model, and it is workable.

To figure out the law of vehicle lane departure during distracted driving and to reduce the collisions caused by lane departure, twelve drivers participated in road driving test; and the vehicle movement states of 398 distracted driving samples were collected. The means, the variances and amplitudes of the lane departure distances were selected as the indicators to characterize the level of lane departure. The correlation test and the fitting analysis between the distracted driving time and the three indicators were carried out. By analysis of the variation of the three indicators during common driving and distracted driving, the relationship between distracted driving time and lane departure was derived. The results indicate that the lane departure during driving with distraction is larger than that without distraction. The lane departure increases with the distracted driving time, and it increases more and more quickly. When the distraction time exceeds 3.0 s, the vehicle lane departure rises rapidly in a short time.

The degree of diffusion of chloride in concrete is influenced by the stress. In this paper, chloride diffusion coefficients of C30 and C60 concretes are tested using conductivity method. The chloride permeability is evaluated according to CCES01-2004 Standard. Results show that the chloride permeability of C30 concrete is weaker than that of C60 concrete. The chloride permeability under tensile stress is stronger than that under compressive stress. Under compressive stress, as the stress ratio increases, the chloride diffusion coefficient decreases first and then increases. The chloride permeability is the lowest under stress ratio of 0.35. Under tensile stress, the chloride diffusion coefficient continuously increases with the increase in stress ratio, and when stress ratio reaches 0.35 it increases sharply. Under comprehensive consideration, when the stress ratio is 0.35 the chloride permeability is the lowest and it has minimal impact on the durability of concrete.

In order to study the stress behavior and diaphragm effect of steel-concrete curved composite beam, model test and finite element analysis were conducted on six simple model beams stiffened with diaphragms. The span-radius ratio and the number of diaphragms were taken as the design parameters. Under the concentrated load at the middle span of the beam, the whole process behavior, section strain and interfacial slip were analyzed. The results show that, with the increase in span-radius ratio the bending-torsional failure of the steel-concrete curved composite beam becomes more obvious; while the number of diaphragms has little influence on the bending-torsional failure. At positions close to the diaphragm the tangential and radial strains are small inside the curve and large outside the curve, which are reverse at position far from the diaphragm. The tangential and radial slippages between the concrete slab and steel girder both increase with the span-radius ratio; while the number of diaphragms has little influence on the tangential slippage, but the radius slippage increases close to the diaphragm. The diaphragms have large effect on the transverse distribution of the strain, and the end diaphragms can enlarge the torsional stiffness of curved composite beams apparently.

To improve the “trade-off” relationship between be and NO_x emissions, the effect of N₂ and CO₂ dilution on combustion and NO_x emissions was experimentally investigated. The experiments were arranged on a six-cylinder Natural Gas (NG) engine under 1450 rpm and 50% load while keeping other conditions unchanged, e.g. the engine speed, spark timing, throttle opening and fuel amount are constants. The results show that, compared with CO₂ dilution, N₂ dilution can improve the “trade-off” relationship between be and NO_x emissions when NO_x emissions are reduced to the same levels. The main factor decreasing the NO_x emissions is the dilution effect for N₂ dilution and the thermal effect for CO₂ dilution, respectively. Compared with CO₂ dilution, the combustion rate of NG-air mixture is faster when using N₂ dilution, which improves the fuel economy at the same NO_x emissions or dilution ratio.

A higher thermal efficiency plate-fin liquid-cooled radiator was matched for the hydraulic system of wheel loader by experiment and simulation method to solve the overheating problem when working in summer. The changes of the internal flow field and temperature field of the radiator were studied under different conditions. The simulation results show that the heat transfer e4fficiency of the serrated fin is obviously higher than that of the straight fins. Therefore, serrated fins were selected in order to ensure that the hydraulic system could work properly under normal temperature. The pressure characteristics of the radiator met the specific requirement. The flow uniformity of the coolant reached the best when the deflector angle was equal to 45°. The problem of insufficient heat dissipation hydraulic oil radiator was solved by the new radiator. The results of this study may provide reference for the loader cooling system optimization.

In order to diminish the frictional force between the vane tips and the stators and achieve the clearance compensation, a novel double-stator multi-speed motor with roller vane tips was proposed, in which the vane tips roll instead of sliding on the stators. The vane tip rollers are forced on the inner and outer stators under centrifugal force and the hydraulic pressure, thus forming oil tight working chambers. To demonstrate the mechanism of its sealing, force analysis was carried out on the rollers, and the experimental platform was set up. It turned out that the roller-vane structure could acquire rolling while maintain the volumetric efficiency, which transfer the contradictions between the vane tips and the stator curves and provides a new idea for designing the double-stator multi-speed motor.

In order to explore the effect, the mechanism and the potential of energy saving in using series hybrid electric bulldozer, an analytical formula was deduced to present the relationship between the Equivalent Fuel Saving Ratio (EFSR) and the influencing factors. Combing simulation and analytical method, the mechanism of energy saving and the impacts of components' efficiencies and drive cycles on the energy saving effect were analyzed. The limit values of the EFSR were calculated. Results show that under typical drive cycle, the energy saving mainly originates from the higher components' efficiencies in the diesel-electric routine of the powertrain; the engine efficiency has the largest influence on the EFSR among all components' efficiencies. With the increase in bulldozing resistance or vehicle speed, the EFSR decreases. Moreover, the energy saving limit under various optimization measures can be calculated using the proposed analytical formula.

A measure is quite necessary to provide an assembly feasibility analysis of integrated transmission in the design stage. A visual simulation platform is built with virtual reality according to the characteristics of complex product. A model of interactive operation tool is proposed with the data glove. Also a mixed bounding box collision detection method and path planning technology of human-computer interaction are investigated. The precise positioning method of part is developed based on the reconstruction of assembly feature elements. A type of armored integrated transmission is taken as an example to verify the proposed methods. Results show that the assembly feasibility analysis can be achieved by this integrated assembly technology at the design stage of complex product.

In order to improve the mixing efficiency of different reactants in microscale, a study on optimization of the structure and working parameters of the Y type pulsing micro mixer is conducted, in which the effects of the structure and parameters on mixing performance are taken into consideration. By simulation analysis, the channel section size, entrance angle, entrance flow rate and pulsation frequency are optimized. Based on the optimized structure and working parameters, a test prototype was made in lab. Using chemical reaction probe method, the prototype is tested. After detecting the size and distribution of gold nanoparticles by controllable synthesis, the mixing performance is evaluated synthetically. The test results indicate that when the entrance flow rate and working frequency are ascertained, there exist corresponding optimum values of the section size and flow rate of the Y type pulsing micro mixer. The entrance flow rate and working frequency are important parameters which influence each other. A certain flow rate corresponds to an optimum mixing frequency.

The power generation capacity of piezoelectric cantilever beam generator can not fully play due to that its resonance frequency bandwidth is small when capture low-frequency variation. To overcome this problem, modal analysis of the piezoelectric cantilever beam was carried out. Combining with the requirement of self-power of automobile tire pressure detection system and the characteristics of the vibration mode of the cantilever type power device, a scheme was proposed. In this scheme, the bending and torsion vibration modes were utilized to constitute the piezoelectric cantilever generator; the bending mode and torsion mode were decoupled by the distributed mass block arrangement. Finite element simulation was carried out. The simulation results show that, under the condition that the first bending mode frequency is 12.6 Hz, by adjusting the mass block distribution, the natural frequency of the flexural mode can be reduced to 17.2 Hz. Under the same condition, the power generation capacity of the improved piezoelectric cantilever beam generator is about 1.4 times of that of the traditional centralized mass piezoelectric cantilever beam generator.

A kind of piezoelectric inchworm motor was designed based on inverse clamping and triangulation amplification. The motor can be self-locked under power-off. The output displacement of the clamping is amplified by the structure of triangulation amplification. The principle of the motor was demonstrated by experiment. The no-load and load characteristics were tested in the experiment. The clamping forces under the states of power-on and power-off were obtained and the factors influencing the forces were analyzed. When the driving frequency is 50 Hz, the motor is in optimized state. The maximum driving force is 2.1 N and the no-load velocity is 0.38 mm/s; when the frequency is 70 Hz, the motor researches the highest velocity of 0.43 mm/s.

A new method was put forward based on Westhoff meshing transmission interference evaluation system. The method was used to judge whether there exists interference between the enveloping tooth profile and pulley tooth groove of the double helical synchronous belt transmission. Then a new double helical synchronous belt was designed and the conjugated tooth profile transmission model was induced on the basis of the double helical transmission characteristics. It is shown that there is no meshing interference in the new double helical synchronous belt compared with the Eagle PD; the higher and steeper the belt tooth, the stronger the resistance ability to climb. The new normal tooth profile is effective to improve the contacting strength while the radius is larger and the instant engagement line is longer, where the point of the conjugated circular arc is on the pitch line.

Inspired by the quantum theory, a Compound Quantum-inspired Structuring Element (CQSE) based on morphological dilation operator is proposed to enhance shock response component of fault vibration signals. The CQSE considers both the local feature and stochastic characteristics of the signals, therefore, COSE adjusts its height dynamically according to signal. First, the basic expression of Quantum-inspired Structuring Element (QSE) is proposed. Second, the kurtosis, which is employed to describe the local feature of shock response signals, is utilized to generate the height of Single Form in Real Space (SFRS) of QSE; the normalized signal, which is employed to describe the stochastic characteristics of signals, is utilized to compute quantum-inspired probability of each SFRS. Third, combing quantum-inspired probability with mathematical expectation, the CQSE for morphological dilation operator is obtained. Finally, the CQSE is applied to bear fault diagnosis and enhance the fault information effectively.

Taking the cooling system of anti-collision beam hot stamping die as the research object, the heat transfer in this system is analyzed based on the convection heat transfer and fluid principle combined with the boundary layer theory. A design scheme of the cooling system is put forward, and its cooling effect is simulated using software Fluent. The cooling system is numerically optimized until the simulation results meet the design requirements. Experiment is carried out to verify the numerical optimization. Results show that in the die design, larger pipe radius (R), smaller pipe sidewall spacing (L), and smaller vertical distance between pipe top and die surface (H) lead to larger sheet metal cooling rate. Among them, H has larger influence on die cooling rate and L has larger influence on the maximum temperature difference. The martensitic transformation of the sheet metal is realized under the premise of uniform cooling by partial adjusting parameters R, L and H. Furthermore, in the design, the structural strength and thermal stability of the cooling system for long-term work are considered.

Interface Heat Transfer Coefficient (IHSC) between blank and tools is the key factor to obtain the temperature field, stress and strain fields and microstructure distribution of boron steel hop stamping parts. By measuring the temperature changes of the blank and die in the process of quenching combined with finite element analysis and the inverse heat transfer model, the relationship between the interface heat transfer coefficient and temperature was obtained. The results show that IHSC ranges from 1970 W/(m²·K) to 3960 W/(m²·K) when the temperature of the blank decreases from 770 ℃ to 200 ℃. IHTC decreases as the temperature of the blank decreases. However, the release of latent heat during the transformation from austenite to martensite results in the discontinuity of IHTC at 420 ℃. The distribution of IHTC is almost the same under different environmental temperatures and quenching mediums. The IHTC values of the die surface temperature as quenching medium are higher than those at the location 1 mm below the surface of the die.

High-Current Pulsed Electron Beam (HCPEB) was employed for the surface irradiation of solid solution Mg-Gd-Y-Nd alloy. The microstructures of the specimens before and after the irradiation were characterized in detail using X-Ray Diffraction (XRD), Optimal Microscopy (OM) and Scanning Electron Microscopy (SEM). The microhardness and corrosion resistance of the irradiated samples were also examined. The experiment results indicate that the sample surface was remelted after HCPEB irradiation. The electrochemical corrosion resistance of the irradiated surfaces was improved obviously. Grain refinement on the surface, the formation of remelting layer and the solid solution strengthening effect of rare earth elements are believed to be the dominating reasons for the improvement of the hardness and corrosion resistance performance.

In the simulation of hot forming of high-strength steel, the phase transformation process can be simulated using current commercial finite element analysis software; however, the forming damage process can not be simulated. To overcome such problem, a damage-phase transformation constitutive model for high-strength steel hot forming is established. By writing user defined material subroutine of this mechanical model, which is used in LS-DYNA software, the phase transformation process and forming damage process can be simultaneously predicted. Furthermore, hot forming virtual test of cap-shaped parts is conducted. Results show that the maximum value of the volume fraction of martensite appears in the flange portion of the cap-shaped parts, the average volume faction is 98.5%; while the maximum forming damage concentrates in the middle of the side wall of the parts, and its value reaches 0.7. The effectiveness of constitutive model is verified in this test, and this research may provide guidance for actual production of hot forming of high-strength steel.

In order to effectively evaluate customer requirements in product planning, an analysis method was proposed by integrating rough set theory, DEMATEL method and Kano's model. First, the attribute importance principle of rough set theory is adopted to determine the fundamental importance of customer requirements. Second, considering the influence of the correlations between customer requirements, the fundamental importance of customer requirements is modified by DEMATEL method. Third, based on the competitive analysis of Kano's model, the adjustment function of importance rating is built, which integrates the customer demand category, competitive analysis and importance rating calculation. Finally, the weight vector, which reflects the final importance rating of the customer requirements, is obtained by normative approach. A case study of the development of new farm tractors demonstrates that the proposed analysis method is effective and feasible.

Water filling and drainage system is a typical nonlinear, time varying, variable structure system. A fractional order PI^λD^μ control scheme for such system is proposed. First, the mathematical model of the water filling and drainage system of a rubber dam is established. It is proved in theory that the fractional order PI^λD^μ controller has better robust properties for the system. Then a fractional order PI^λD^μ controller is designed for the system in a practical project, which achieves good control effect. Finally, an actual control curve of constant current is given using the fractional order PI^λD^μ controller. Practice proves that the proposed control scheme is efficient and the system possesses good static and dynamic performance and certain robustness.

Under the environment of practical applications, some tags still stay in the identification range of the reader. Based on the AQS algorithm, a highly efficient Radio Frequency Identification (RFID) adaptive tracking tree anti-collision algorithm is put forward. First, arriving tags and stay tags are identified in the way to divide and conquer. Then, a ternary tree collision tracking algorithm is designed for the arriving tag identification. Finally, a method of merging inquiry string and building branch tree for adaptive adjusting inquiry queue is proposed to identify stay tags, which implements a single inquiry string can identify multiple stay tags. Theoretical analysis and simulation experiments show that the performance of the proposed algorithm is better than that of existing AQS algorithm.

A dynamic voltage restorer(DVR) with superconducting magnetic energy storage (SMES) is presented in this paper, which protects sensitive loads from unbalanced grid voltage sags. Firstly, the schematic representation and general principles of the DVR are described. Then based on the load voltage oriented vector analysis, the voltage injection magnitude, load power swing and phase shift are discussed. In addition, a new concept of restoration techniques is put forward to inject minimum energy for DVR during compensation. Simulation analysis and experiment results of the DVR system, show that the proposed method could minimize the injection real power of DVR with given apparent power and the customer side voltage is restored effectively.

As the number of topics k should be given in advance in LDA model, therefore, to choose the optimal number of topics k cyclical calculation is needed, which will increases the complexity of the algorithm. To solve the problem of choosing the optimal topics k, the LDA topic increments training algorithm is proposed. First, the entropy of word-topic probability is taken as the extract standard of fuzzy word in the iterative process, and a new topic is generated by the extracted fuzzy word. Second, the dimension of the global parameter β (word-topic probability matrix), dirichlet parameter α, and number of topics k, are increased in the process of variational inference. Third, the variational training algorithm is executed with the transformed global parameters β, α and k. Finally, the LDA topic increment training algorithm is executed cyclically, which is stopped while the likelihood is converged to complete the increment training of k. The effectiveness and feasibility of the proposed algorithm for optimal topics number k is verified by experimental analysis on real datasets.

In this paper an optimization strategy of dynamic task migration for molecule docking is proposed based traditional task migration method. The mean and variance of the number of sequential jobs of each node are analyzed to obtain the coefficient of variation reliability, thus, to increase the efficiency and security of molecule docking tasks. An incremental data migration is carried out from the source node to a high reliable target node, and the time of downtime copy is shortened. The results of case study show that the efficiency and security of molecule docking tasks are improved.

Plagiarism in student programs is a common phenomenon, which decreases the credibility of assessment. However, manual detection loads a heavy burden on the teachers. To solve this problem, a plagiarism detection model is proposed. First, student programs are converted into token sequences through lexical analysis. Then, the token sequences are hashed to digital sequences. Then, the frequent closed sequences are mined by the BIDE algorithm. On this basis, the similar code fragments are detected and the plagiarism programs are identified by the calculated similarity. Experimental results show that, compared with the commonly used toll MOSS, the proposed method is more precise. It can not only give accurate statistical information of similar programs, but also explicitly display the plagiarized code fragments.

In order to eliminate the effects of optical radiation between adjacent projection screens in CAVE systems, an optical radiometric compensation model is established according to the spatial distribution of optical luminance of cosine radiator. Besides, an optical radiometric parallel compensation algorithm is designed based on GPU technology. By analysis of current CAVE systems, it can be concluded that parallel compensation algorithm can achieve the best compensation result through multi-level compensation. In the first compensation level, more than 80% of optical radiometric influence can be eliminated and only about a quarter of the image is severely affected. When the overall multi-level compensation among multi-projection images is considered, the video displayed on the projective system of large-scale orthogonal multi-screens must be pre-compensated. Therefore, a fast optical radiometric compensation method is proposed according to the analysis of compensation results. This method is applied in two special theaters of large-scale orthogonal multi-screens, and it is demonstrated that images with uniform color and brightness within the distinguishing range of human eyes can be achieved.

Classical palmprint feature extraction algorithms can not extract the shallow fine lines in a better way. To solve this problem an algorithm based on Non-Subsampled Contourlet Transform (NSCT) and mathematical morphology multispectral palmprint line feature extraction is proposed. First, NSCT is used to obtain multi-directions, multi-scales and sub-bands are selected and strengthened according to the shallow fine line characteristics. Then, in light of the spectral characteristics, the coefficients are fused and NSCT inverse transformation is made. Finally, using morphological thinning treatment, the shallow fine palm lines are obtained. Experiments using multispectral palmprint image acquired from self-collected palmprint database show that the propose algorithm can extract shallow fine lines more clearly and abundant.

Under complex geological condition, grid subdivision technology influences the accuracy of multiphase flow simulation. To meet the need of grid subdivision for multiphase flow simulation, a new algorithm is proposed to construct Perpendicular Bisection (PEBI) mesh of arbitrary shape with any constraints. This proposed algorithm for generating 2D and 3D PEBI grid includes five steps, e.g. point layout, triangle subdivision, unqualified triangles identification and point layout adjustment, Thiessen polygon generation, and topology reconstruction. In this process, various constraints (vertical wells, horizontal wells and faults) are reduced to point constraints, line constraints and area constraints, respectively. To provide a flexible way of arranging the point location, several common methods were expounded. The PEBI grid was created base on Thiessen polygon topology reconstruction. The proposed algorithm was applied to PEBI grid generation of several typical complicated geological conditions. The results demonstrate the feasible, simple and flexible characteristics of the proposed algorithm.

An electronic image stabilization algorithm based on sea-sky line was presented to solve the slosh problem in the video acquired from the on board catadioptric omnidirectional vision system. Combing with the characteristics of sea-sky line in omnidirectional image, a feasible method based on optimal edge estimation was proposed to get the sea-sky line elliptic equation. The omnidirectional image stabilization model is built based on sea-sky line. The application of the sea-sky line image stabilization algorithm is introduced and the method of reconstructing the invalidated regions using sky frame is given. The actual test was carried out using sequential panoramic images, which were obtained in marine environment. Experimental results show that the proposed algorithm is fast and effective to solve video image stabilization for on board catadioptric omnidirectional vision system. The average computation time is less than 50 ms/frame, which has good application effect.

In order to achieve reliable spectrum sensing by users under the condition of low Signal-to-Noise Ratio (SNR) and fading channel in cognitive radio systems, a new covariance matrix spectrum sensing algorithm based on stochastic resonance and Multi-input-Multi-output (MIMO) technology is proposed; and the calculation method of the decision threshold is derived. Simulations show that the performance of the proposed algorithm is batter than the algorithm without introduction of the stochastic resonance and MIMO technology. When the number of antennae is large enough, the proposed method can achieve good performance at low SNR.

The Enhanced Distributed Channel Assess (EDCA) mechanism is adopted by IEEE 802.11p Medium Access Control (MAC) layer, which is used in Vehicular Ad hoc Networks (VANETs). The performance of MAC layer is studied to satisfy Quality of Service (QoS) requirements of messages with different applications. The two-dimensional Markov chain is proposed to study the backoff process of the EDCA mechanism, in which different types of messages, internal collision and the frozen mechanism are taken into account. On this basis, the normalized throughput, the drop rate and time delay of messages are studied. The results show that the value of normalized throughput decreases with the increasing number of vehicles; while the drop rate and time delay are opposite. However, the higher priority category has the larger value of normalized throughput and the lower value of drop rate and time delay, which verifies that the IEEE 802.11p can provide QoS for different messages. The analysis results can also provide theoretical basis for the deployment of VANETs.

The performance of tracking association algorithm using target topology information is influenced by the estimation accuracy of the reference target state because of sensor bias. To solve such problem, a grey track anti-bias association algorithm based on centroid topology of reference is proposed. First, the algorithm takes the position and course of the sensor commonly observed targets' fusion centroid as the reference, and constructs the target topological vector. Then, the subsequential modified grey association analysis algorithm is used to calculate the grey association degree of the sensors. Finally, the global optimal track anti-bias association is carried out using the grey association degree as test statistical vector. Simulation results show that the performance and robustness of the proposed algorithm are better than the traditional algorithm apparently in random cross targets and dense parallel formation environment.

In traditional local matching algorithms, the window-based aggregation methods are usually used to obtain disparity map; also, the segmentation and plane fitting methods are used in disparity refinement. The performance of the algorithms is greatly dependent on the window size, and precision of segmentation and data fitting methods. In this paper, a stereo matching algorithm based bilateral filter is proposed, which is called double weighting aggregation. The fast cost aggregation method and hyperbola are employed to smooth the matching cost. The proposed algorithm is beneficial to improve the stereo matching accuracy since it is independent on the window size. The simulation results show that the proposed algorithm can obtain higher accuracy disparity map in low-texture and depth discontinuity regions. Besides, superior disparity map and 3D reconstruction results are also achieved in real stereo images.

A novel content-aware image resizing mechanism based random permutation was proposed for the dynamic programming in seam carving algorithm. The proposed algorithm exploits visual saliency to get a random scrambled energy vector, which is extracted uniform to protect important image content. This algorithm can efficiently avoid the local distortion caused by excessive deleting non-important area. The simulation results show that the proposed algorithm gets a better visual effect. Compared with the seam carving algorithm, the proposed algorithm not only effectively protects the important image content, but also increases the speed for image resizing and avoid image distortion.

Traditional testing methods of electromagnetic interferences can not observe individual airborne equipment when multiple devices are working. Furthermore, the existing blind sources separation algorithms can not solve the problem that the number of observed signals is less than the number of source signals. To overcome these shortcomings, a new underdetermined blind sources separation algorithm is proposed to separate electromagnetic interferences. The method is applied to harmonic signals with sparse characteristics. The algorithm constructs mathematical abstraction of electromagnetic interferences by underdetermined blind source separation mode. First, the single source area is found by calculating the ratio of observed sampling points. Then, the number of sources and mixture matrix are estimated using Hough-windowed method. Finally, the mixed signals are separated based on angle difference sorting method. Simulation results show that the effectiveness and accuracy of the proposed algorithm that the average correlation coefficient between separated signals and sources is 0.9936. Monte Carlo simulation results show the higher stability and noise immunity, and measured results demonstrate the feasibility of the algorithm.

Existing color image watermarking algorithms based on Quaternion Discrete Fourier Transform (QDFT) do not fully utilize the four dimensional (4D) QDFT frequency domain, which only deal with achromatic watermarks and suffer from watermark energy loss. To overcome these drawbacks, a blind dual watermarking algorithm for color images is proposed to embed dual meaningful watermarks (one is color and the other is binary) into four components of each QDFT coefficient of a color host image. For unit pure quaternion k, first, the relationships existing between the components of QDFT coefficients and the Discrete Fourier Transform (DFT) of three RGB color channels are established; then, the symmetrical constraints were presented, which one must follow when modifying QDFT coefficients; finally, QDFT, Arnold transform and a multiple redundant embedding strategy are combined for watermarking. Experimental results demonstrate that the proposed method achieves a reasonable trade-off between the fidelity and robustness and outperforms the existing schemes.

To investigate the suppression of the speckle noise in laser active imaging, a denoising method based on Time-Domain Constrained (TDC) in signal subspace is proposed and a laser active imaging system based on range-gating ICCD is constructed for experiment. First, homomorphic transformation is performed to convert the multiplicative noise to additive noise. Second, wavelet transformation is performed to estimate the covariance of speckle noise. Third, the noise image is decomposed into signal subspace and noisy subspace, and singular value decomposing is used to estimate the dimension of the signal subspace. The covariance of clean image is decomposed using eigenvalue decomposing, and denoising estimating matrix is computed. Fourth, the denoising estimating matrix is convolved with noisy image. Finally, the inverse homomorphic transform is carried out to get the denoised image. Experiment results indicate that, compared with classical Lee, Frost and Kuan filtering, the proposed method has advanced denoising performance and consts less computation time.

Since the current remote sensing imaging techniques can only get sparse sampling remote images, which are unable to accurately estimate the target state information, so the traditional association method using state features is not suitable for remote sensing image target. If the time independent image features are selected as the associative volume, the ambiguity induced by the association multiple targets in big scene can not be handled. To solve the above problem, a multi-scale autoconvolution feature matching and simulated annealing optimization algorithm is proposed. First, the MSA features are extracted and the matching probability between features is calculated to construct the whole association cost matrix. Then, the adaptive temperature updating function and the double threshold are set to improve the simulated annealing algorithm for quick search of the global optimal solution. Experimental results show that the proposed algorithm can effectively use the feature information of remote sensing image, eliminate association ambiguity and solve the problem of multi-target association efficiently.

In the maximum likelihood algorithm proposed by Benvenuto base on mixed noise model, the noise effect during iteration is not taken into consideration and the Point Spread Function (PSF) is assumed to be known and unchanged. This leads to the unstability of the image restoration. Under the condition of noise existence and PSF unknown, an image denoising algorithm is proposed as preprocessing, and the parameter estimation of PSF is introduced into iteration of the maximum likelihood and is dynamically updated. Finally, the Wiener filter with estimated PSF is utilized to improve the quality of the restored image. Experiment result demonstrate that the quality of the restored image is obviously improved, which proves the stability and noise resistance of the proposed algorithm.

In this study, porous β-tricalcium Phosphate (β-TCP) bioceramic is prepared by the following steps. First, calcium nitrate and 2-phosphonic acid-1,2,4-tricarboxylic acid (PBTC) are used as raw materials to synthesize the precursor; second, β-TCP power was prepared by dehydration concentration and high temperature sintering; third, β-TCP power is taken as the matrix, stearic acid as porogen and PVA as binder to prepare the moudles by press molding; finally, β-TCP bioceramic is prepared by sintering of the moudles. The compositions of the β-TCP bioceramic are analyzed using X-ray diffraction analysis, scanning electron microscopy and EDX spectroscopy. Degradation experiments are carried out using the specimens with four levels of porogen, 15%, 20%, 25% and 30% respectively. Results show that the specimen with 30% of porogen has the best degradation performance. EDX analysis and scanning electron microscopy observation confirm the generation of hydroxyapatite materials on the surface of the β-TCP bioceramic.

In superheated steam fluidized bed drying, the operation pressure significantly influences the heat and mass transfer and the steam-particle two-phase flow with nonlinear characteristics. Base on the two-dimensional unsteady model of drying process of rapeseeds, numerical simulation was carried out to investigate the influence of operation pressure on the kinetics of superheated steam fluidized bed drying. Under negative pressure, near atmospheric pressure and high pressure, the relationship between the operation pressure and maximum drying rate was quantitatively analyzed respectively. For superheated steam fluidized bed drying of granular products with the inlet steam temperature and flow rate, the values of the optimal operation pressure were obtained. Simulation results show that, with inlet steam temperature of 358 K, flow velocity of 2.5 m/s and particle diameter of 1.0 mm, the optimal pressure is 0.02 MPa; with inlet steam temperature of 403 K, flow velocity of 2.5 m/s and particle diameter of 1.0 mm, the optimal pressure is 0.1 MPa; with inlet steam temperature of 443 K, flow velocity of 2.0 m/s and particle diameter of 2.0 mm, the optimal pressure is 0.2 MPa.