A vehicle mass estimation method based on longitudinal frequency response characteristics is proposed for wide application for different types of vehicles. First the longitudinal acceleration and wheel speed information obtained from intelligent connected vehicle are used to derive the amplitude-frequency function between acceleration and wheel speed signal based the vehicle longitudinal dynamics model. Then, the amplitude ratio of the acceleration of the center of mass to the wheel speed at different frequencies is obtained. Finally the vehicle mass is calculated by least square fitting. The CarSim-Simulink co-simulation results show that the estimation accuracy of the proposed method is above 93.9%, which can meet the requirement of vehicle control for multi-vehicle coordinated collision avoidance system.

In order to investigate the influence of installation errors on the Transmission Error (TE) of hypoid gears, a finite element model was built and the TE was simulated in both static and dynamic steps. The results demonstrate that the static and dynamic TE curves of hypoid gear are in substantial agreement, except that oscillation exists in the dynamic TE curve during the initial engagement. When the gear rotational speed is stable, the two types of TE curves are the same. The higher the rotational speed, the longer the stability time required for dynamic TE. The installation errors would translate the TE curve integrally. The influences of the installation errors on the TE from large to small are in the order: the shaft angle error, the pinion axis error, the offset error and the ring axis error. The influences of the pinion axis error and the offset error are related to the directions of the installation errors.

For multi-disc clutches, an analytical model of average interfacial pressure and torque is established with the effect of spline friction. The pressure attenuation coefficient of friction pairs is derived and the sensitivity is analyzed to investigate the parameters, which may affect the clutch pressure. The results show that the friction coefficient greatly influences the pressure attenuation. The axial pressure significantly attenuates with the increase in interfacial friction coefficient and spline friction coefficient. The effect of the spline friction coefficient is more obvious than the interfacial friction coefficient. The spline pressure angle has little influence on the axial pressure attenuation. It is found by experiment that with the increase in friction pairs, the average torque of single friction pair dramatically declines, and the increase amplitude of total torque decreases. The proposed model is verified effectively by the comparison of the simulated results and experiment data, and the model can better reflect the actual pressure and torque characteristics of the multi-disc clutch.

A novel multi-objective optimal design method is proposed for gearhead and ball screw two-stage driven electromechanical Brake actuator (EMB). With consideration of important factors, such as two stage driving, discrete transmission ratio, dynamic resistant torque, transmission inertia and feasibility constraints related to the component characteristics, this method can applied to determine the optimal combination of motor, gearhead and ball screw. First, the loads and motion laws were analyzed based on the dynamic models of EMB for emergency braking and anti-lock braking on dry asphalt road. Then, all feasible motors and ball screws, which can drive the load and satisfy the requirement for actuator size, feasible torque and speed of motor, characteristics of the planetary gears and ball-screw, were selected among the catalogues. Second, the planetary gears were designed according to the combinations of feasible motors and ball-screws to minimize the size of the planetary gear with the constraints of Hertzian pressure and bending fatigue strength, respectively, thus all feasible combinations of motor, gar ratio and ball-screw were achieved. Finally, the multi-objective optimal combination was obtained with respect to actuator weight, starting acceleration, air gap closing time during braking, and motor output torque.

In current research of vehicle driving cycles only some parameters are selected as characteristics of the driving cycles, which lacks the analysis of the characteristics of driving cycle state transition. To solve this problem, based on the characteristic parameters extracted from typical driving cycles, this paper adopts the principal component analysis and K-means clustering to obtain three kinds of typical driving cycles, which represent the vehicle driving characteristics under different traffic conditions. The state, transition probability and eigenvalues of the state Transition Probability Matrixes (TPM) under the typical driving cycles are analyzed, and the analysis results are consistent with that of the characteristic parameter analysis under three kinds of typical driving cycles. It is shown that the eigenvalues essentially influences the efficiency of cycle generation of highway, suburb and city roads, revealing the reasonability of construction two-parameter TPM in designing driving cycles.

To solve the connection technique for ultrahigh-strength steel 22MnB5 and aluminum 7075 sheets, a process called Hot Riveting Quenching (HRQ) clinching to connect autobody parts of ultrahigh-strength steel and aluminum alloy dissimilar materials is proposed. By using the good formability at elevated temperature and quenchability of steel 22MnB5, effective joints between steel 22MnB5 and 7075 aluminum alloy are obtained by HRQ clinching. The feasibility of HRQ is confirmed by the formation and quenching finite element models. The punch radius R_t, die radius r_a and depth h_a are optimized by study of the connecting joint shape. The uniaxial tension finite element analysis and actual tests of the connecting joint show the connecting joints have the best mechanical properties when the forming temperature is 700 ℃ and the punch stroke is 5.3 mm.

A state-preference survey on drivers' route selection is conducted by designing the simulation scenario with real-time traffic condition in Vissim. A route selection forecasting model is constructed with binary logit model. The impact of habit and traffic condition on the drivers' route decision is estimated using this model. Results indicate that both the habit and traffic condition impact the drivers' route selection, however, the influence of habit is greater than the traffic condition. Besides, the effects of both factors vary with the changing traffic condition. A real-world forecasting experiment proves that the proposed model can be applied to predict the selection probability between habit route and alternative route according to traffic condition with satisfactory prediction accuracy. The results can be applied to real-time prediction and recommendation of travel route in vehicle navigation software.

In order to alleviate the conflicts of traffic supply and demand, improve the resident trip structure and mode, multiple variables impacting the travel mode choice were defined based on the random utility maximization theory with Nanjing City as a specific case. Mixed Logit (ML) model was established for analyzing and interpreting the influence and interaction mechanism of behavioral characteristics among household properties, individual attributes, trip information and the locations of trip ODs. The outcomes of ML model were analyzed by statistic regression. Results show that competitiveness of slow modes (non-motorized transport) become better if the time requirement is not high. However, with travel time increasing, the advantages op the slow modes are gradually weaken. Moreover, in suburbs and long distance trips, public transports (including metro) become more attractive to passengers. The results of statistic regression may help urban planners and transportation policy makers to integrate limited road resources systematically to ensure the resident travel comfortable, convenient and efficient.

To solve the problem that it is difficult to reasonably determine depth of rigid layer, a novel method based on inertial point is proposed. First, the multiple deflection basin curves are detected within the section to be evaluated. Then, the parameters of inertial point (the offset distance and the deflection) are determined by obtaining the minimum of the root mean square error. Finally, the particle swarm optimization algorithm is applied to perform the iteration to back-calculate the rigid layer depth and subgrade modulus from the parameters of inertial point, whose deflection does not vary with the modulus of the upper layer. Analysis of theoretical simulation shows that the proposed method can accurately back-calculate the rigid layer depth with average back-calculation error of only 1%. The filed data show that the inertial point actually exists in the deflection basin curve measured on the asphalt pavement surface, and can be used to back-calculate the rigid layer depth and subgrade modulus. Compared with existing method, the variation of subgrade modulus back-calculated from the proposed method is lower, and the regional differences can be considered.

In order to better link the chemical analysis with the pavement performance of asphalt binders, improve the durability of asphalt pavement in cold areas, Fourier Transform Infrared Spectroscopy (FTIR) and Dynamic Shear Rheological (DSR) test were used to analyze the changes of asphalt rheological parameters and characteristic functional groups under freeze-thaw cycles. The relationship between the rheological properties and the content of characteristic functional groups of asphalt was discussed based on gray relational entropy analysis model. The microstructure of the asphalt before and after the freeze-thaw cycle was characterized by Scanning Electron Microscopy (SEM). Results show that water-temperature aging reaction occurs in the asphalt during the freeze-thaw cycles. Under different freeze-thaw cycles, the sulfoxide and carbonyl groups in the asphalt FTIR spectrum show a significant increase. The logarithm of asphalt complex modulus has a negative growth relationship with the increase in temperature. The phase angle changes linearly with the temperature. The rutting factor exhibits and exponential decay pattern with temperature. The asphalt chemical compositions influence the rheological properties in the order carbonyl,asymmetric aliphatic,sulfoxide. The asphalt film structure appears obvious folds and flocculent areas after water freeze-thaw cycles.

As one of the effective approaches to reduce NO_x emission of diesel, Urea Selective Catalytic Reduction (Urea-SCR) can catalytically convert toxic NO_x emission to nitrogen and water by accurately controlling the amount of ammonia injection. However, there still exists problem such as non-measurable states in Urea-SCR. To resolve this problem in the Urea-SCR feedback control system, first, the chemical reaction mechanism of DCR system is analyzed and a model containing both upstream and downstream (master-slave) elements is introduced. Second, a nonlinear reduced-order observer is designed to observe the non-measurable states by utilizing the concentration measurement downstream ammonia and NO_x, meanwhile, the stability of the observer is analyzed and the value range of the observer parameter is calculated based on stability analysis. Finally, the effectiveness of the proposed approach is testified by simulation in enDYNA employing FTP75 cycle test procedure.

To adapt to a more complex mixed system, an integrated three-phase flow pulsation Micro Mixing Chip (MMC) based on piezoelectric actuation technology was proposed. Using the mixing degree as the evaluation index of mixing effect, simulation and optimization analysis were carried out, and the structural parameters and working parameters of the MMC were optimized. A MMC with the size of 100 mm × 50 mm × 50 mm was fabricated by injection molding and bonding processes. In order to test the mixing performance of the chip, experiments of the liquid phase synthesis of silver nanoparticles were carried out. The results show that when the width and the entrance angle of the mixing channel of the MMC is 0.4mm and 120 degree respectively, the working frequency is 200 Hz, and the entrance flow-rate is 3.5 mL/min, silver nanoparticles with average diameter of 29 nm are synthesized by the controllable microfluidic chip, with high productivity, fine morphology and good monodispersity, which demonstrate that the MMC has good mixing performance.

The passive intervention and oil storage of accumulator may bring a lot of uncertainties to the electro-hydraulic control. In this paper, the internal principle that the valve controls the cylinder in a crane luffing mechanism is studied. The modular model of the pilot valve, the main valve, the accumulator and the cylinder is built, and a contrast model without the accumulator is also built. Simulation and experiment results show that the passive intervention of the accumulator causes speed fluctuation of the cylinder in the outstretch stage, but it does not affect the cylinder in the retraction stage. According to the system pressure, the reduction of pump oil supply is equal to the oil discharge of the accumulator. The method can effectively solve the problem of speed fluctuation. Experiments verify the compensation scheme.

A new hydraulic muffler is designed based on the mechanism of pressure ripple reduction by accumulator group with several accumulators installed in series. This design takes advantages of the characteristics of noise elimination and structure of Helmholtz muffler. The mathematical models of the accumulator group and the new hydraulic muffler are developed. The effects of a single accumulator, an accumulator group and the new hydraulic muffler on the pressure ripple reduction are investigated by numerical simulation using the Method of Characteristics (MOC) and FORTRAN language. The simulation results are compared with experimental data, which verifies the simulation model and calculation method. It is shown that the new hydraulic muffler can more effectively reduce the pressure ripple than the traditional accumulator, meanwhile its structure is smaller than the accumulator group, which is important in engineering application.

In order to solve the problem of load distribution in construction machines, an estimation method of piecewise mixed load distribution based on Akaike Information Criterion (AIC) K-means is proposed. First, according to Luise method, the chi-square test values of the normal distribution, logarithm normal distribution and Weibull distribution are calculated. Then, the corresponding distribution of the minimum test value is chosen as the fitting function of the piecewise mixed distribution. Finally, the formula expression of the distribution is obtained through the maximum likelihood estimation. The proposed method is applied to the outlet pressure load time history of the excavation operation the excavator, and compared with the existing method. The result obtained by the proposed method passes the chi-square test. The simulated data of 1000 groups are used to conduct feasibility analysis and the estimated parameter error range is 0~18%.

In order to realize precise control of photoelectric turntable, the dynamic characteristics of the vertical shaft of a type of photoelectric turntable are investigated. First, the relationship between the natural frequency of the shaft and the turntable is analyzed, and the dynamic model of the vertical shaft is built. Then, the finite element model is established, modal analysis is carried out and the excitation and boundary conditions are loaded according to the actual working conditions. Using explicit integration, the response of the turntable is solved. Finally, the experimental platform for researching the dynamic characteristics of the vertical shaft is set up. Servo scanning experiment is carried out to obtain the characteristics of the shaft in time domain and frequency domain. Results show that the natural frequency obtained by kinetic analysis is 180.4 Hz, by simulation is 190 Hz and the experiment result is 174 Hz, the maximum error is less than 10%. According to the analysis, a reference scheme to increase the natural frequency of the vertical shaft system and to select the control bandwidth is proposed. This scheme provides the reference for research on the dynamic characteristics and optimization of the shaft system.

The winch system is one of the main components of crane hoisting device, which accounts for 37% of the total energy consumption of the whole machine with lot of potential energy loss during work. This paper studies the potential energy recovery and reuse of the winch system. First, the energy loss mechanism in the process of winding down is analyzed. On this basis, an energy recovery system is proposed. Second, the mathematical model of the recovery system is established, and the calculation formula of the energy recovery rate is derived. Finally, taking certain type of 25t off-road tire crane as the research object, an experimental platform is set up. The experiment results validate the rationality and feasibility of the proposed energy recovery system that the recovery rate of the potential energy is about 45% ~ 65%.

In order to study the internal pressure pulsation characteristics of vertical mixed-flow pump, by model test, the impeller inlet and vane outlet pressure pulsations were collected with different impeller blade placement angles of -2°, 0° and 2°. By Fourier transformation we found that the peak values of the pressure pulsation of the impeller inlet and vane outlet have certain regularity. With different blade placement angles, the peak value of the pressure pulsation of the impeller inlet is always larger than that of vane outlet, especially in small flow area. The micro and macro stability relationship of the pump is established by comparing the peak value of the pressure pulsation with the head and shaft power variance, and the stability of the pump can be obtained from the pressure pulsation in the vicinity of the high efficiency area. However, both in large and small flow areas, the pressure pulsation is no longer able to reflect the stability of the pump. By analyzing the frequency domain map, we can get four conclusions. First, the impeller inlet is affected by the number of blades, mainly by blade frequency. Second, the vane outlet is less affected by the number of vanes. Third, the amplitude of pressure pulsation of vane outlet approaches maximum at one times of the frequency. Last, the pulsation frequency is smaller under the optimal working point of each blade. Under each blade angle of the pump efficient area, the peak value of the pulsation of the impeller inlet and vane outlet reaches the minimum. When under 1.15 times of the optimum flow rate, the peak value reaches maximum. The impeller inlet is about 1.24 times of the peak value in the optimal working condition, while, the vane outlet maximum is about 1.57 times. The best run area of the mixed-flow pump is 0.75 to 1.15 times of the optimal head. The peak value of pressure pulsation is obviously increased when the running head is out of this range.

The spatial buckling of sucker rod in tubing is important basis to analyze rod and tubing wear in vertical pumping well. In this paper, first, the spatial buckling model of entire sucker rod is divided into three-section model, four-section model and five-section model. Then the differential equations of each section of each model are established, and the continuity conditions of the displacement, rotation angle, bending moment and the tangential shear at the connecting points are derived respectively. Finally, numerical integration method is used to solve the equations, in which the differential equations are transferred into nonlinear algebraic equations, thus, the numerical simulation of the entire bucking configuration of sucker rod string is realized. The simulation results show that, when the bump end load of the rod is much higher than the spatial buckling critical load, the five-section model is more reasonable than the three- and four-section models. The contact force, helix angle of the helical section, the length of the helical section and bottom suspend section of three- and four-section models have certain gaps with five-section model. The results errors of the distribution contact force and the length of the helical section obtained by simplified reduced order equations in previous studies are larger compared with the solution of the complete helical buckling section equation. The wear position and contact pressure are different with different subsection methods. The simulation method may provide reference for further study of rod and tubing wear and prediction of rod life.

A simplified finite element model of the dummy chest is established based on sensitivity analysis of the structural material properties. The model is characterized with coarse and fine meshes and also satisfies the experimental calibration. In order to improve the anthropomorphic precision of the simplified model, the engineering issue is abstracted as a multiobjective optimization issue, which aims to reduce errors of both chest displacement and pendulum force between the simplified dummy and the physical dummy simultaneously. Considering sternum material parameters as the optimization parameters, high precision surrogate models of objectives are constructed by polynomial response surface method. A MBNWS algorithm is proposed, which is based on BFGS method in conjunction with weighted sum technique and Frisch method. The Pareto optimal solution and its front of the optimization problem for dummy chest are achieved by the MBNWS algorithm. The optimized dummy chest structure can simulate the mechanical response of the physical dummy chest more accurately during vehicle collision. In addition, the MBNWS algorithm is proved fast and efficient, and it is suitable to solve multiobjective optimization problem in engineering practice.

A non-invasive estimation and analysis system for lower limb joint moments was developed based on a piecewise three segment Sit-to-Stand (STS) biomechanical model and a double-sensor difference based algorithm. The wearable sensor system, composed of force sensors, customized accelerometer and gyroscope, worked with vitro implanted sensors. Compared with conventional approach, the number and variety of sensors were reduced in this sensor system. Compared with the results from reference camera system, the developed wearable inertial sensor system is available to analyze the lower limb biomechanics of patient during the rehabilitation training with high degree of accuracy. In the future, the system could be applied for the detection and estimation system of human STS rehabilitation training and to the control of exoskeleton rehabilitation robot.

Based on Taguchi orthogonal test, the multi-objective optimization problem of dissimilar thickness DP1180/DP590 resistance spot welding was studied using grey relation analysis. The optimum parameters were derived by considering the responses such as nugget diameter, indentation rate and lower peak load by difference analysis. Analysis of variance (ANOVA) was used to analyze the effects of different parameters on the responses. Based on the results, welding current 9.5 kA, welding time 22 cycles and electrode force 8.48 kN evolved as the optimized parameters. Under the optimized parameters, the nugget diameter, indentation rate and peak load of the spot joint are 6.67 mm, 17.70% and 19.49 kN, respectively. The joint in with the optimized parameters ensures the strength and reduces the indentation rate. The influence degrees of the spot welding parameters on the measuring factors are in the order: welding current, welding time and electrode force.

Three kinds of metal rods with different ductility were used to study the strain ranges and mechanical properties of metal under different stress states by tension and torsion tests. The Bridgman method was used to measure the hardening curve from the beginning of necking to the final fracture. Comparison and analysis of the two test results show that the uniform strain ranges of the metal rod in the torsion state are larger than those in the tension state because of the difference of mechanical stability. Due to the difference of the fracture mechanism under different stress states, the strain ranges before fracture of metal in torsion test are larger than those in tension test. So the total strain ranges measured in torsion test are larger than those in tension test with Bridgman method. The Bridgman method has limitations, which is only applicable to metals with large ductility and weak hardening ability, while, torsion test is versatile and suitable for metal with different properties. Comparing with the tension or compression state, the metal rod exhibits different degrees of “softening phenomenon” in the torsion state, that is, the metal is more likely to reach plastic yield in the torsion state, and the hardening ability and the ultimate bearing capacity are obviously weakened.

The chromium element is alloyed on 45# steel by High-Current Pulse Electron Beam (HCPEB) with pre-coating to obtain high quality alloyed layers. The microstructure and properties of the alloying layer are studied by XRD, OM, SEM, TEM and multi-purpose microcomputer electrochemistry analyzer. Analysis results show that, the formation an alloyed layer with the depth of about 4~9 μm on the surface is observed. The solid solution and diffusion of Cr element occurs on the surface of the substrate. C atoms generated by the dissolution of the cementite combine with the chromium to form a small amount of nano-grained carbide Cr₂₃C₆. The surface micro-hardness and the corrosion resistance of 20 steel after HCPEB alloying are remarkably improved compared with the original sample.

In order to solve the problem that the soil compaction pressure is difficult to monitor in real-time, a real-time pressure measurement of profiling elastic press roller was introduced based on soil cone index. In this method, the real-time values of pressure were acquired through the measurement of the eccentricity of profiling elastic press. The clay soils with three moisture contents, 13.9%d.b., 21.2%d.b. and 27.8%d.b., were used in the experiment. From the experimental results, the relationship between eccentricity of the profiling elastic press and the soil solidity, and that between the static pressure and the soil solidity, were established. With equivalent relationship of the soil cone index, the data curve was fitted and the model equation was established between the eccentricity and pressure in the top layer of soil with depth of 0mm-100mm. The model equation can get accurate quantification and real-time measurement of the pressure to provide technical support for the adjustment of the profiling elastic press roller during operation.

To overcome the current deficiency in studying the Rollover Stability (RS) of Semi-mounted Agricultural Machine Unit (SMAMU, including a tractor and semi-mounted machine), a new method to characterize the RS of SMAMU is proposed. The Lateral Load Transfer Ratio (LLTR) is chosen as the evaluation indicator of RS, the rollover mathematical model is established and quasi static simulation is carried out. Through ADAMS dynamic modeling, the simulation results are in good agreement with the mathematical model, which verifies the correctness of the theoretical model. The effects of the parameters of SMAMU on the RS are discussed and the sensitivity of the influencing factors is analyzed. The LLTR is correlated to the height of center of gravity, the wheel-base of the tractor, the weight of the SMAMU, the wheel-center-distance, the distance from the center of gravity to the tow point and the height of tow point. The results show that the height of the center of gravity and the wheel-base of both the tractor and the semi-mounted machine are the important factors affecting the RS. Besides reducing the height of center of gravity or increasing the wheel-base, reducing the height of the tow point or increasing the distance from the center of gravity to the tow point can also improve RS. This work may provide reference for the optimal design of SMAMU.

For the non-constant exercise workload (power) due to the fluctuation of pedaling rate in cardiopulmonary function and training system, a new magnetic-resistance generator was designed to adjust the resistance real-timely, instantly and precisely. The constant power can be maintained independent of the pedaling rate within certain range by applying fuzzy PID control theory. To validate the effect of constant power control, experiments were carried out on the improved cardiopulmonary function evaluation and training system and on the Monark cardiopulmonary function evaluation and training system, respectively. Results show that, for the improved system, the instant power curve fluctuates within 8 W of the target power curve, and the control error between the average power during two minutes of the test and the target power is less than 2 W as the pedaling rate changes in the range of 50 r/min to 70 r/min. The new system overcomes the influence of non-constant power output due to the fluctuation of pedaling rate. Compared with the Monark system, the new system improves the constant power control accuracy by 2 W and reduces the control error under the same target power and the same change of pedaling rate.

Measuring the acoustic pressure of standing wave is the basis of acoustic levitation. The non-axisymmetric acoustic field within the resonance cavity is analyzed. Firstly, the acoustic pressure distribution on the typical cross-section of the acoustic field in the third levitation mode is obtained by COMSOL simulation. The simulated acoustic pressure is Radon transformed to obtain the simulated LDV velocity output, which is compared with the experiment results to verify the relationship between LDV velocity output and acoustic pressure distribution. Then, based on Filer Back Projection (FBP) algorithm, a self-written MATLAB code is used to reconstruct the LDV velocity output in the experiment and obtain the acoustic pressure distribution of the cross-section, which is compared with the COMSOL simulation results. The identification effect of the non-axisymmetric standing wave acoustic filed is verified.

To solve the problems of high complexity and information loss in the process of measuring graph similarity, a method to calculate the distance of vertical dimensional sequences is proposed, which is used to measure graph similarity. Using this method, the graph is converted into the generalized tree, which is regarded as the vertical dimensional sequences. This method simplifies the graph similarity measurement to the distance calculation of the sequences. The vertical dimensional sequences not only obtain labels, in-degrees and out-degrees information of vertices, reflect level structural property of vertices, but also reserve the path information of graph. Compared with the existing graph similarity methods, this method involves more graph information in the process of graph similarity measurement, and decreases the time complexity to O(n²).

Exogenous miRNAs are cross-kingdom regulatory in bacteria and viruses, but whether exogenous plant miRNAs are stable in the human body and are involved in cross-kingdom regulation is still controversial. Only by cross-border modeling on the basis of a comprehensive analysis of the human high-throughput miRNA data, and design of effective biological experiments, the human exogenous plant miRNA presence, access pathways and regulatory role can be revealed. In this paper, high-throughput sequencing data based on human serum were used as the study objective and were analyzed by bio-calculation method. The possible human exogenous plant miRNAs were screened by using the RNA data of human and plant as the reference group. Based on the principle of miRNA regulatory mechanism, the possible target genes of plant miRNAs interfering with human mRNA were obtained. A network model of plant miRNA-human mRNA was constructed to analyze possible cross-kingdom regulation. Nine core modules were excavated by constructing a plant-human cross-kingdom regulation model. The results show that exogenous plant miRNAs are involved in the regulation of biological process such as human amine metabolism, alcohol metabolism and fatty acid metabolism.

In real-time environment, the traffic information is dynamic. This paper proposes a hybrid dynamic path optimization algorithm in real-time environment, which is based on A^* algorithm and combined with pruning algorithm. This paper also puts forward the optimization strategy by introducing the local optimal and global optimal intelligent storage of particle swarm optimization and fuzzy time window into the hybrid dynamic path optimization algorithm. The pruning threshold based on the local optimum is an effective way to control the size of the threshold. The fuzzy time window is applied to algorithm optimization time constraints and the control of the simulation time so that the algorithm can better adapt to the real-time environment. In order to verify the optimized strategy, simulation with the hybrid dynamic path optimization algorithm is conducted in which data is based on the New York map. Simulation results verify the effectiveness of the optimization strategy. Also the performance of the proposed algorithm is compared with the A^* algorithm, which demonstrate that the optimization strategy has certain adaptability and can be applied to Dynamic Route Guidance System (DRGS).

This paper proposes an effective prediction model for choosing the second major based on the Particle Swarm Optimization (PSO) enhanced Kernel Extreme Learning Machine (KELM), which is called PSO-KELM model. In this model, the PSO strategy is adopted to adaptively determine the optimal parameters in KELM. The PSO-KELM model is compared with other two competitive methods, including Support Vector Machine (SVM) and a KELM is optimized by grid search technique, on a major selection dataset via a 10-fold cross validation scheme. The results clearly confirm the superiority of the proposed PSO-KELM model in classification accuracy, area under the receiver operating characteristic curve (AUC), sensitivity and specificity.

The traditional Network Topology Discovery (NTD) algorithm does not verify the authenticity of data sources, resulting in the possibility of the discovery results being deceived. Therefore, in the internet of things environment, a new NTD algorithm is proposed, which can resist routing spoofing attack. The undirected graph of the internet of things is described, and the PSNP request is used to query the source router of the suspicious routing information, so as to realize the authenticity detection and resist routing proofing attack. The information in SNMP management information base MIB is used to distinguish routers and switches, which provides the basis for network layer topology discovery. The algorithm flow of network layer topology discovery in SNMP protocol is given. The link layer topology discovery process is introduced by combing bridge switching and bridge spanning tree algorithm to realize link layer topology discovery. Experimental results show that the proposed algorithm can effectively resist routing proofing attack and has strong network topology discovery performance.

Most of existing image annotation methods are based on the same topic space. In fact, categories are important information to determine the image annotation words, different classifications of images present different objects. In this paper, a new image annotation method based on Corr-LDA model is proposed. In this method all sorts of images are placed in different topic spaces, and the image annotation model suitable to each category is learned. Experiment results on Labelme and UIUC-Sport datasets show that the proposed method has better performance than other methods.

Taking the actual physical cache as the measurement of the buffered video, an adaptive algorithm based on physical caching of the video is proposed. The algorithm adjusts the bitrate of the video according to the buffer occupancy rate and the estimated throughput of the Internet. The performance tests are conducted under two virtual network conditions and two real network conditions. The results show that the proposed algorithm can reduce the sensitivity of the video bitrate to the change of the buffer and avoid the buffer frequent fluctuation. Compared with the traditional algorithm, the proposed algorithm is superior in terms of Quality of Experience (QoE).

An assessment method of the Electromagnetic Pulse (EMP) sensitivity of vehicle engine system is proposed based on Hierarchical Bayesian Networks (HBN). Considering the randomness of the parameters such as the position of the electromagnetic interference source, the polarization angle, component sensitivity and so on, the proposed method can estimate the failure probability of the engine system under strong EMP. The EMP propagation model is established by Event Tree Analysis (ETA), and the risk probability of the electromagnetic environment is determined. The coupled path of the engine of the engine system is analyzed using the Electromagnetic Topological (EMT). By correlation of invalidation of the same layer cells, as well as HBN integrating ETA and EMT, the assessment model of engine system for EMP sensitivity is established, and the failure probability formula from the component level to system level is derived. A case study for the pulse susceptibility assessment of the vehicle engine against high-latitude EMP illustrates the model parameter acquisition method and calculation process. In addition, vulnerability of vehicle engine against Ultra Wide Band (UWB) high power microwave is also presented to demonstrate the applicability of the proposed model.

To timely complete the energy supply for the “hungry” sensors in Wireless Rechargeable Sensor Networks (WRSNs), a cluster and low-energy route mobile charging algorithm, called Clustering Low-energy access Prediction (CLP), is proposed based on energy prediction. The WRSN adopts the unequal clustering and multiple-hops routing protocol, and it chooses the node with the lowest energy in each cluster as the head node of that cluster. The mobile charger provides energy just for the cluster head nodes and collects the energy information of sensors of each cluster. After each round of the charging schedule, the mobile charger sends the energy message to the base station, and the base station adopts the Markov model to forecast the energy consumption of the sensors in each cluster in order to optimize the selection of charging target for next new charging schedule. Compared with TSP algorithm network, the results of the simulation show that CLP algorithm can improve the network utility by nearly 20%, and the ability of data transmission of nodes is increased by nearly 17%.

A real-time triggering transmission delay measurement model and a data transfer model are proposed to solve the problem that the delay time of triggering instruction received by the data acquisition node in distributed test system is different and unknown. Furthermore, a high-precision time interval measurement method with the use of delay chain cycle comparison is proposed to achieve the propagation delay of the synchronous triggering pulse. The delay measurement provides high-precision delay data for subsequent calibration of the synchronization triggering error. The test results show that the proposed method can realize high-precision measurement of the synchronous triggering pulse transmission delay in distributed test system.

Three efficient methods are proposed to solve three key problems in Duffing oscillator detection system, including the system perturbation by input noise, the synchronization of phase position of driving force and target signal, and the judgment of system output state. First, a reverse phase change method based on the critical threshold dictionary is proposed, where the dictionary is built on the monotonic property of the critical threshold with the change of noise intensity, so that the input signal perturbation is reduced efficiently under low Signal to Noise Ratio (SNR). Second, a double system joint detection method is proposed to solve the problem of phase position synchronization of driving force and target signal. Third, a state of system motion judgment method based on output phase space graph representation is proposed and its feasibility is proved mathematically. The embedded representation of the detection results is fulfilled with low computation and high precision. Finally, the Duffing oscillator detection model suitable to engineering practice is built under low SNR, by which the lowest detection SNR is reduced significantly with constant detection probability.

The optical system of actual human eye was established by the wave-front aberrations, corneal topography and ocular axial length. With the goal of ideal imaging at the retina of actual human eye, an individual objective lens for had-mounted projective display with 68° large field was developed, which could correct not only the aberrations of the objective lens, but also that of human eye. The imaging quality on the living retina was analyzed. It was shown that the distortion is 2%, the lateral color aberration 10.0 μm, and the retina image resolution is 50 pl/mm. The individual objective lens is less than 18g weight after production and assembly without diffractive-optical element, which can meet the demands of modern head-mounted display in high performance, large field of view and light weight structure.

Due to the rapid improvement of the resolution and frame rate of the high-speed CMOS Image Sensor (CIS), image acquisition systems claim a higher level requirement for data bandwidth and cache capacity to dealing with the huge amount of real-time data from the sensor. According to this situation, this paper presents an implementation method for high-speed CIS data acquisition system based on FPGA and USB 3.0. The acquisition system is constructed by following parts: design of system hardware circuit, FPGA and UBS 3.0 software design, PC operation software design, system testing and debugging and measurement results. The results indicate that this system can use the maximum capacity of UBS 3.0, meanwhile, achieve zero Symbol Error Rate (SER) during the image reception process. Therefore, the system satisfies the requirement of real-time ability and accuracy of data for the current high-speed resolution CIS.