Based on fluid-solid interaction method, simulation analysis of the flow around the external rearview mirror was carried out to investigate the mechanism of fluid-induced vibration, and the main vibration forms were described. First, the rigid external rearview mirror model was investigated to get the drag coefficient C_d, and lift coefficient C_l, which provide a comparison basis for the study of fluid-induced vibration and verify the feasibility of the simulation program. Then, the flow around the external rearview mirror was simulated by numerical method to investigate the vibration characteristics of the mirror under different velocities. The changes of the drag and lift coefficients, vibration amplitude, frequency of vortex shedding and other parameters with the velocity were obtained. Results show that strong vibration of the mirror occurs when the vertex shedding frequency is approach to the structural natural frequency of the external rearview mirror, and the vibration strength is far greater than the impact strength of the wind.

The hydraulic retarder may change the distribution ratio the braking power of the tractor-semitrailer that negatively affects the braking stability. To solve this problem, a gear-shifting strategy of the hydraulic retarder is proposed. The strategy is designed to actively change the gear of the hydraulic retarder based on the relationship between the rear wheel of the tractor and the wheel of the semitrailer. With goal to optimize the locking sequence of the tractor-semitrailer, the Matlab/Stateflow is applied to design the gear-shifting strategy. Then this strategy is associated with the dynamic model of the tractor-semitrailer built with Matlab/Simulink to study the braking sequence during straight braking and the lateral motion during straight braking with lateral force. Simulation results show that the proposed strategy can help keep the optimum braking sequence, decrease the braking distance on the road with particular tire-road adhesion and improve the lateral stability of the tractor-semitrailer.

To respond to dynamic customer demands, a route updating strategy with updating time is proposed to online adjust the routes. Moreover, a charging model is developed to allocate the charging stations to the routes with charging demands in transit. A case study is given to demonstrate the simulation process of the route updating strategy. In addition, the parameter analysis based on the running time and the extra cost is presented. The results show that the proposed strategy has less updating time and can quickly respond to dynamic customer demands and reduce cost. the strategy running time and cost increase with the updating time, the dynamic costumer demands and the charging times. The longest strategy running time is within the acceptable range, which indicates that the strategy is feasible and practicable.

In order to improve the understanding and analysis of motion patterns of vehicles, a hierarchical trajectory clustering algorithm is developed according to spatial and temporal characteristics of the vehicle trajectories in the entrances and exits of freeway. In view of the vehicle trajectories are different in length, but in the same direction, the improved Hausdorff distance was proposed and applied to measure the similarity of trajectories. The improved fuzzy C-means hierarchical clustering algorithm of trajectories was further established, in which trajectories were first clustered into different paths according to the spatial geometric position of the trajectories, and then trajectories belonging to the same path were further clustered according to the vehicle speed to obtain the final results with spatial and temporal degree. Experiments in the entrances and exits of freeway were carried out. The results confirm that the proposed trajectory clustering algorithm not only has strong adaptability to the inherent motion pattern of the scene, but also ensures the accuracy and reliability of the clustering results.

In order to describe car following behavior in real road traffic, the car following status is divided into strong car-following, weak car-following and free travel sub-status. Considering the difference of driver reaction time in different space headways, a space sensitivity and velocity difference functions, and a full velocity difference model based dynamic reaction time (DRVM) is established. The stability condition of this model is obtained by using linear stability theory. Three experiences, vehicle acceleration, vehicle emergency deceleration and change of traffic state from free flow to congestion, are simulated in MATLAB. Compared with Optimal Velocity Model (OVM) and Full Velocity Difference Model (FVDM), simulation results show that the starting lag time of DRVM is 1.5 s, the speed of congestion spreading is 17.76 km/h, and the deceleration performance is improved by 25% compared with that of FVDM. The DRVM can be accord with the actual situation and close to stable traffic flow.

In order to get scientific and reasonable secondary task driving safety evaluation index system, an experiment was conducted and the parameters of eye movement and vehicle running states were collected using an eye tracker and a driving simulator equipment. Then, the variation rules of these parameters during driving were studied. Using gray cluster analysis theory and rough set theory, 7 evaluation indexes were screened out from 17 indexes, and a streamlined evaluation index system is built. On this basis, the Fuzzy Analytic Hierarchy Process (FAHP) was used to determine the weight values of the evaluation indexes. Results show that the eye movement behavior of the first-level indexes and the throttle opening of the second-level indexes are the most important ones.

Using a high fidelity driving simulator with eight degrees of freedom, the effect of low visibility in haze weather condition on the driving behavior of three Car-Following (CF) stages (acceleration, deceleration and steady following stages) are analyzed from both engineering CF models and psychological-physiological CF model. The results show that the low visibility environment in haze weather condition has significantly different impacts on driving behavior of different CF stages. In acceleration CF stage, the drivers' sensitivity in changes of relative speed and spacing, as well as maximum desired acceleration under haze weather condition are significantly lower, 29.3%, 33.1% and 17.4% respectively, than that under clear weather condition. Meanwhile the heterogeneities in driving behavior are substantially larger in haze weather condition. In the deceleration stage, drivers' sensitivity in changes of relative speed, maximum desired deceleration and expected maximum deceleration of the leading vehicle under haze weather condition are significantly larger, 31.7%, 17.8% and 16.3% respectively, than that in clear weather condition. Whereas, the drivers' sensitivity in change of the spacing decreases by 32.1% in haze weather condition. In steady CF stage, the drivers have larger sensitivities in changes of relative speed, 41.6% higher in average in haze weather than that in clear weather, and have slightly smaller maximum desired acceleration and deceleration. However, there are no significant differences in desired speed and drivers' reaction to the change in spacing under different weather conditions. Moreover, the action points of acceleration and deceleration indicate that the drivers under low visibility in haze weather adopt quicker acceleration to follow the leading vehicle more closely, and are more cautious to take quicker braking action to avoid collision. The main findings of this paper provide references for setting-up of microscopic simulation for emergency traffic evacuation in case of low visibility in haze weather condition.

A feedback control model of pedestrian counter flow was established to avoid pedestrian flow blocking in bidirectional corridors. The fundamental diagram of bidirectional pedestrian flow incorporating the conflict characteristic was derived using the social force model under the uniform state. To accommodate the possible inhomogeneous pedestrian density along the corridor, the bidirectional corridor was divided into several sections for different directions. A system dynamics model of pedestrian counter flow was proposed using the conversation law of pedestrian mass and the state space equation. To satisfy the moving demand of pedestrians in both directions, the equalization control objective was proposed based on the user equilibrium theory, and the linear feedback control model was established. The proposed control model can maximize the output flow of the corridor, thus improving the service level of the corridor by adjusting the walking speed of pedestrians and the corridor input flow in real time. The proposed model has the capability to serve as a general control method of both pedestrian flow and vehicle flow.

In order to fast and effectively acquire and process the panoramic image of traffic accident scene to meet requirements of the accident scene rapid investigation, a bionic compound eye array is designed. This design is inspired by combination of the visual mechanism and structure of fly compound eye and crab eye. The array is composed of a plurality of image sensors. First, each sensor uses its own independent imaging channel to complete the image acquisition. Then, the images of all sensors are stitched together to build the panoramic image. The design principle of the bionic compound eye array is analyzed. The experiment platform is built by establishing the mathematical model of the bionic compound eye array. Imaging experiment results show that the bionic compound eye array for traffic accident can realize the large field of view image and obtain the panoramic image.

In this paper, first, the stiffness distribution function of steel-concrete composite beam under vehicles is derived, in which the effect of share slip of the composite beam is considered. Then, the undetermined coefficients are used to express the vibration functions of the composite beam and the vehicles. Further, based on the matrix transfer method, the vibration equation of the vehicle-beam vibration system expressed by the undetermined coefficients is established using the deformation compatibility and the force equilibrium condition. The natural frequencies and mode shapes of the steel-concrete simply supported beam under vehicles can be calculated by this vibration equation. Finally, the validity and reliability of the presented method are verified by finite element method.

The traditional calculation model of Wilhelmy plate method has two deficiencies: the effect of liquid film pressure on the surface of asphalt binders during the receding process is out of consideration and the surface energy components are sometimes unsolvable. To overcome these two deficiencies, taking the asphalt binders, in which anti-stripping agents were added, and acidic gravel as the test samples, the traditional model and the model based on film pressure were used to calculate the surface energy of the asphalt binders, respectively. The moisture stability indexes ER1 and ER2 of the asphalt mixtures were analyzed. In addition, the moisture stability performances of the test samples were assessed using the water-boiling test following the guidelines of ASTM D3625. The comparative results show that the film pressure calculation model is able to eliminate the two deficiencies, and the moisture stability performance ranking of the asphalt mixtures predicted by the model agrees well with that determined by the water-boiling tests.

An evaluation function was established to analyze the influence of ash distribution on Diesel Particulate Filter (DPF) pressure drop. The variables in this function include the channel diameter, channel wall thickness, ash mass and the soot. Results show that the relative magnitude of ash, wall and soot permeability decides the trend of DPF pressure drop changing with the ash distribution. When the ratio of wall and ash permeability A= 0.1 and the ratio of wall and soot permeability S=2, the evaluation function is positive, and the DPF pressure drop is lower when ash locating on the wall of the inlet channel than the ash locating at the rear of the inlet channel, and passive regeneration is adopted. When A= 10 and S=2, the tendency reverses, and active regeneration is taken. Wall thickness, channel diameter, ash mass and soot mass affect the extent of the influence of ash distribution on DPF pressure drop.

The effect of butanol/diesel blend fuel on combustion and emission characteristics of a compression ignition engine is investigated. The action mechanisms of several boundary parameters, such as butanol fraction, Exhaust Gas Recirculation (EGR) rate and combustion phasing, are analyzed. The results show that with the increase in butanol fraction, the ignition delay is extended and a higher proportion of premixed combustion is obtained, thus, better combustion timeliness can be achieved. The smoke and NO_x emissions are reduced simultaneously with a combined application of EGR and blended fuel. However, this compromises the engine output and the indicated thermal efficiency. In order to recover the lost power output due to the joint use of ESR and blended fuel, the combustion phasing is adjusted to match the specific ESR rates used in the tests. With an appropriate strategy, the power output of the engine can be recovered with almost no influence on the overall emission.

In the process of the digital hydraulic pumps/motors displacement shifting, the torque impacts problem which influences the ride performance has always been found. Some researches had been made for torque impact mechanism and its inhibition. According to the experiment results, in the process of digital control there exists a different degree of hysteresis between pressure establish-ment/disestablishment and signal outgoing in different diameters of reversing valves, which causes pressure superposition of multi-stage pump and further leads to the additive effect of impact. In order to solve the above-mentioned problem, on the basis of the re-sponse time for reversing valves and system pressure impact, a step sequence control strategy had been formulated. Then the control strategy had been simulated by using AMESim software, and verified the strategy by way of experiments. Experiment results show that the step sequence control strategy reduces impact degree during the process of displacement shifting by 23%, relieves the sys-tem's torque impact effectively, and satisfies the dynamic continuity principle of the system.

The temperature model and heat transfer model among inner-film-floating-ring-outer -film of floating ring bearing were established, in which the temperature gradient of the floating ring was taken into consideration. The effect of the temperature gradient on the lubrication performance of the floating ring bearing was discussed. Results show that, taking the radial temperature gradient of the floating ring into consideration, the inner-film temperature increases, the overall frictional power loss and end discharging capacity slightly decrease. With outer eccentricity ratio of 0.4, when the inner film clearance increases from 0.02mm to 0.04 mm, the inner film temperature and total power loss are decreased by 16.0% and 15.9%, respectively. The total power loss increases with the inner circle radius. The lubrication performance of the floating ring bearing can be improved remarkably by appropriately decreasing the inner circle width.

The quantitative sector fan-shaped oil pad bearing capacity calculation does not take into account the effect of centrifugal force, and the traditional calculation method lacks experimental verification. To solve this problem, first, the bearing capacity model of the fan-shaped static bearing oil pad is derived, in which the centrifugal force is considered. Then the overall dynamic model of the turntable is established. The hydrostatic turntable experiment scheme is designed, and experiments are carried out. The experiment results are basically in agreement with theoretical calculation results that the error is within reasonable range, which verifies the feasibility of the model and the overall kinetic equation for the calculation of the bearing capacity of the fan-shaped oil pad considering of the centrifugal force. The model and the analysis conclusion of this work may provide theoretical support for practical production and the service performance of the turntable.

Considering the background of dynamic test of armored vehicle in the field and based on integrated vehicle test system, a new host platform, which integrates acquisition, display, storage and analysis together, is designed by LabVIEW language. According to the functional requirements of the system, five functions including testing task configuration, real-time data display, offline data playback, test data management and test data analysis are designed to realize the integration of the system functions. An experimental verification environment is built on the PXI platform to validate the above mentioned functions of the host platform. Results show that the design of the host platform meets the needs of more than 200 signals test of the armored vehicle. In addition, the flexible system configuration feature, ell-integrated design and friendly visual interface provide convenience for the dynamic tests of real vehicle in the development and improvement of armored vehicles.

Using a high-accuracy optical torque transducer, a starting torque test system for harmonic drive is developed based on servo loading. The test range of the system is 0~0.07 N·m and accuracy is better than ±1.0×10^-3 N·m. A servo motor is controlled in current mode with output torque increasing slowly, to apply driving torque on the measured object. A high-precision torque transducer, which is placed between the servo motor and the object, is used to acquire the driving torque exerted on the measured object. When the object begins to rotate continuously, the driving torque applied on the object is regarded as the staring torque. The detailed design, analysis of accuracy and experimental verification are conducted for the torque test system. Experimental results show that the test system can realize measurement automation of starting torque for harmonic drive with high testing accuracy.

Facility Layout Problem (FLP) has significant impact on manufacturing efficiency. It involves determining the optimal placement of different types of facilities within the boundaries of the workshop. FLP can be categorized into Static Facility Layout Problem (SFLP) and Dynamic Facility Layout Problem (DFLP). DFLP takes possible changes into account in the product demands over multiple periods. The facilities may need be dynamically placed several times to accommodate various demands accordingly. This work studies the DFLP under uncertain product demands. First, to solve the FLP caused by uncertainty and dynamics of material requirements between facilities, a method of dynamic facility layout combined with fuzzy-random theory is proposed considering the deficiency of the description of uncertain demands. Then, the main factors causing uncertain demands are analyzed and the uncertain demand are presented by fuzzy random variables. To minimize the material handling cost, rearrangement cost and total distances between various departments and maximize the area utilization ratio, a multi-objective dynamic layout model with unequal-area departments is established under fuzzy random environment. Finally, combining with system layout planning, the optimization method of the position-based colonial competitive algorithm is proposed to obtain feasible optimal solutions for the proposed problem. The rationality of the established model is validated by comparing practical model among the determined demands, random demands and fuzzy random demands. The effectiveness of the algorithm is demonstrated by computational results of the practical problems.

In order to know the formability of 1561 aluminum alloy sheet as a new ship material,its mechanical properties were obtained by tensile test. The multi-point forming and unloading process of aluminum alloy sheet was simulated by finite element software ABAQUS. Simulation results showed that 1561 aluminum alloy material was easy to wrinkle during the forming process and had a large springback. Three-dimensional scanning and Geomagic analysis were carried out, and the results verify the feasibility of using the springback compensation to compensate the springback and multi-steps forming method to solve the winkling in the multi-point forming of 1561 aluminum alloy. At the same time, it is shown that simulation results are reliable.

In order to study the springback mechanism of quenched boron steel with tailored properties, hot stamping experiments of U shape part were conducted using partial die method. A three-coordinate measuring machine NDI PROCMM3500 was used to measure the shape precision of the quenched parts at different holding pressures and die temperatures. The microstructure of the quenched parts were observed using SEM. Results show that the springback angles of the hot region, cold region and transition region decrease as the holding temperatures increases. As the die temperature increases the springback angle of the cold region remains unchanged, but the springback angles of the hot region and transition region decrease. Microstructure analysis suggested that more martensite will cause bigger springback angle, while more bainite will cause smaller springback angle.

The hot stamping process of an anti-collision beam with ultra high strength was analyzed by simulation. The evolutions of the temperature, thickness, microstructure and mechanical properties of the blank in different stages of hot stamping were investigated. The influences of the process parameters, such as initial forming temperature, punch speed and blankholder force, were studied. Then these parameters were optimized and the results were verified by hot stamping tests. Results show that the blank thickness varies mainly in the stamping stage, while the microstructure and the mechanical properties change mainly in the quenching stages, a little springback occurs after the component is unloaded. The influence of the initial forming temperature on the thickness is obvious, and the formability is poor under low initial forming temperature condition. Both over high and over low punch speeds can cause over reduction of the blank thickness. The blankholder setting reduces the fluidity of the metal greatly, which may bring in cracking. For the beam investigated in this work, the optimum process parameters are initial forming temperature of 800 ℃, punch speed of 100 mm/s, and no blankholder setting.

For parts with complex surfaces, a 3D scanning measurement method for full profile was proposed. To obtain the shape deviation of the part, the scanning model was built by reverse modeling and used to compare with the design model. The proposed method was used to measure the blade out arc hollow parts of a large nuclear power steam turbine, and then compared with the designed model. The measuring results show that the largest positive and negative deviations are 2.59 mm and -3.03 mm, respectively. Compared with the traditional special fixture, the 3D full profile measurement method can be used to measure various complex parts rapidly, and it has the characteristics of full data and high precision. To solve the springback problem of the part, springback compensation for the part with complex surface based on reverse engineering was introduced. After springback compensation for the blade out arc hollow part, The molds were processed and tested. The results show that the final largest positive and negative deviations are 1.36 mm and -1.43 mm, which meet the requirement of the shape deviation of that part.

To sole the problem that classical rough set theory can only deal with continuous data, neighborhood rough set theory is employed to analyze the factors that influence the fatigue life of the welded joints. A unified neighborhood rough set model is proposed, which can handle both symbolic and numeric attributes. Attribute reduction algorithm combining forward greedy algorithm and backward pruning algorithm is used to obtain the key factors and to quantitatively calculate the weights of the factors influencing the fatigue life of the welded joints. Experiment results of aluminum alloy welded joints show that the proposed neighborhood rough set model can choose a small number of features and obtain an objective evaluation of various influence factors from the sample data of the aluminum alloy welded joints without any priori knowledge.

To overcome the difficulty of Metal Magnetic Memory (MMM) technique in identification and location of the hidden defect in welded joints, a method of Maximum Likelihood Estimation (MLE) and fuzzy membership degree is put forward. The feature law of critical hidden damage is studied by fatigue experiment of Q235 steel plate with incompletely penetrated weld joint. Four feature parameters are extracted, that are peak to peak value ΔHp(y), mean gradient K_ave, maximal gradient K_max, and maximal limit coefficient mmax. The normal distribution function is employed to calculate the probabilities of the four feature parameters. Then, MLE values are obtained to establish the MLE fuzzy membership model. This model can be used to identify the suspected defect position. Results show that the MLE fuzzy membership model can effectively locate the weld defect and provide a new tool of identification and location of weld hidden damage with MMM method.

Compressive behavior of volcanic ash-Styrene-Butadiene-Styrene (SBS), rubber powder-SBS and SBS modified asphalt mixtures at different temperatures were investigated. Then the deformation mechanism in the compression process of the three kinds of asphalts were revealed. The compressive properties of the asphalt mixture samples were tested at temperatures of 40, 25, 20, 0, -20 and -40 ℃ by static compressive tests. Experiment results show that the compressive properties of the asphalts were significantly promoted above the temperature of 20 ℃ by adding the volcanic ash and the rubber into the SBS modified asphalt mixture, respectively, the compressive strength was increased by 30% by adding volcanic ash. SBS plays a dominant role at the temperatures of 0 ℃ and -20 ℃ in the asphalts, and the compressive strength of SBS modified asphalt mixture is higher than that of the ash-SBS and rubber powder-SBS modified asphalt mixtures. The volcanic ash improves the shrinkage performance of the asphalt mortar when the temperature descends to -40 ℃, and thus the compressive property of the volcanic ash-SBS modified asphalt mixture is better than that of the others.

To overcome the problem that the low measuring precision of the gyroscope leads to degradation of Line of Sight (LOS) stabilization accuracy of photoelectric stabilized platform for aviation, a strong tracking Kalman filter was designed. According to the principle of the time sequence analysis from the random series, Autoregressive method (AR) was adopted to model the preprocessed data measured by the gyroscope. The state-space method was used to design the Kalman filter. In the meantime, in order to increase the control system's robustness, the strong tracking algorithm was introduced to correct the variance of state prediction in real time to construct the strong tracking Kalman filter. The theory and principle of the algorithm were described and applied to the photoelectric stabilized platform for aviation. The results show that the variance of signal was reduced by 44.1% after filtering using the strong tracking Kalman filter, and the dispersion was apparently reduced. At the same time, comparing with the Butterworth filter, the strong tracking Kalman filter shortens the overshoot by 13%, cut down the rise time by 3 ms, shortens the regulation time by 37.5 ms, keeps the platform in good dynamic properties. The study indicated that the strong tracking Kalman filter has strong application value.

In order to improve the isolation degree of disturbance of photoelectric stabilized platform, a friction compensations strategy based on Disturbance Observer (DOB) was put forward. First, the model of velocity loop was established by mechanism analysis, then a disturbance control scheme was proposed. Second, the identifications of the friction model parameters were determined by experiments. Based on the friction compensation control strategy, the DOB control strategy was designed. The accuracy of the strategy was verified by experiments. Finally, in order to test the feasibility and necessity of the control scheme, the aerial photoelectric stabilized platform was installed on the simulation platform, and the disturbance rejection capability of the platform was tested after the friction compensation and DOB were used. Experiment results show that, when the frequency of disturbance is within 3 Hz, the system disturbance isolation degree is increased by at least 14.52 dB. When the system is running at low speed, the tracking performance is improved obviously, and the tracking error is reduced from 0.1959 °/s to 0.0838 °/s. This control strategy can attenuate the mass unbalance torque. It has strong robustness and practical value.

The tandem master cylinder pedal stroke simulator is studied in this work. First, the pedal force transmission ways under normal condition and oil leakage condition of the front and back cavities, and the parameters influencing the pedal feeling are analyzed. Then, the fuzzy adaptive PID control method is adopted to set the influencing parameters online, thus to control the solenoid valve to create a good simulation brake feeling. Finally, the effects of the main parameters of the pedal stroke simulator on the pedal force-stroke relationship are investigated by Matlab-AMESim co-simulation. Results show that the proposed control method enables the brake pedal to meet the design requirements both in normal condition and in oil leakage condition of the front and back cavities.

The software features based on data stream slice are studied, and a new algorithm and evaluation system are proposed for software identification. The definitions about the algorithm, such as data flow, relationship between topological sort, similarity comparison, etc., are given. The key steps of the algorithm are elaborated, including the data dependencies, the structure and reduction of the data dependency graph, the process of relationship topology sorting. Finally, the algorithm and data flow evaluation system of software feature are implemented. System implementation and experiment analysis demonstrate that the research data analysis and theoretical derivation mutually authenticate. The proposed algorithm and evaluation system has theoretical and practical significance for promotion research of software recognition based on software features.

A dynamic reliability-based model, whose load and strength vary with time, is established by using random process and order statistics theory. Then, applying robust optimization design theory, a multi-objective optimization model is proposed for the dynamic reliability-based robust design of mechanic components. Considering the dynamic high-dimensional characteristics of the proposed model, a multiple particle swarm co-evolutionary algorithm based on grey correlation analysis theory is developed for the multi-objective optimization. The leaf-spring is taken as an example for solving the optimal solution set in dynamic environment. Results demonstrate that the proposed method can provide theoretical foundation for dynamic reliability-based robust design of mechanic components.

With the increases in categories, complexity and content of scene images, a categorization algorithm based on multi-level features representation was proposed. First, object attributes based on high-level feature representation were available. Using simple classifiers, the topics of scene images were exported. Then in the same topic, the low-level feature in the image was extracted by the way of fast locality-constrained low rank coding. Meanwhile, in order to reduce the computational complexity, the method of adding local constraint regularization and replacing kernel norm with F-norm in the processing of low rank coding was adopted to achieve detailed understanding of scene images. Achieving scene classification from coarse understanding of object characteristics to detailed analysis of low-level feature, the method can make full use of the progressive and complementary relationship between different features. The experiment results show that better classification effect is obtained.

To solve the problem of load imbalance in Wireless Mesh Network (WMN), an optimization model is used in this work. This model jointly considers channel assignment, routing and interface allocation by making use of mixed integer linear programming. A heuristic algorithm (ILSG) with fast convergence rate is proposed to solve the programming problem. The ILSG algorithm considers network connectivity and load balance to get initial value, which is plugged into iterated local search algorithm to obtain the resource allocation results. Simulation results indicate that the ILSG algorithm can not get the allocation results with a faster convergence speed, but also improve the network performance on the basis of ensuring the fairness.

In this paper, the Signal to Interference plus Noise Ratio (SINR) estimation uncertainty is taken into consideration, and a novel optimal user association and resource allocation strategy is developed when there exists Almost Blank Subframe (ABS) in Heterogeneous Network (HetNet). To meet the demand of UEs with minimal resource, a model is formulated as a min-max regret generalized assignment problem. Simulation results validate the feasibility of the strategy.

As the core infrastructure for the efficient and secure utilization of renewable energy sources, the energy internet is the important strategic resource and embodiment of the comprehensive national strength. The security of energy internet has attracted more serious attentions. In this work, first, the structure of internet was analyzed from logical and network topological structure aspects. Second, the existing research methods are classified into three classes, the security demand-driven method, security model-driven method and the system-theoretical method; and the existing researches are analyzed and compared using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Finally, to solve the problem of vulnerability of isolation and lack of integrated solution in existing security mechanism, a new security mechanism based on Trusted Platform Module (TPM) is proposed. The security model and consuming layer protocol are put forward and security analysis is carried out. The results show that the proposed security mechanism can satisfy the security requirements of the energy internet.

In order to solve the problem of the low precision and large error in the area failure detection of Wireless Sensor Network (WSN), a new model for WSN failure detection is proposed. The signal characteristics of early failure in WSN are analyzed, and the butterfly effect of nodes is proved before and after the failure. By introducing the virtual multidimensional dual model area, and applying the dual characteristics in the space change of the butterfly effect of WSN node when the failure occurring, the risk of the failure existing in the WSN is detected, to ensure that the detection of network failure area does not reduce the service availability conditions. Experimental results show that the proposed method can quantitatively analyze the impact of WSN failure on its security performance without increasing the network burden.

This paper is concerned with the joint estimation problem of Directions of Arrival (DOAs) and Doppler Frequency (DF) for coherence and/or same-direction signals. An eigen-space based modified 2D-MUSIC algorithm is proposed. First, a generalized array signal model is established, which incorporates both DOAs and DFs information. Then, the covariance matrix of the received signals of antenna array is modified through conjugate reconstruction to make it applicable for joint estimation of DOAs and DFs for coherence and/or same-direction signals. On the basis of 2D-MUSIC algorithm, an eigen-space based algorithm for joint estimation of DOAs and DFs is presented, where the information of both signal and noise subspaces is utilized, and this algorithm can estimate the signal power as well. Besides, a modified eigen-space algorithm is given, which can also implement joint estimation of DOAs and DFs for coherence and/or same-direction signals, and it is superior to the modified 2D-MUSIC algorithm in term of estimation performance. Several contrastive simulation results are presented to elucidate the validity of the proposed algorithms.

To solve the problem that mode mixing exists during Empirical Mode Decomposition (EMD), an improved EMD method based on the best feature of intrinsic mode function is proposed. First, the method of boundary local mean is used to deal with the end effect problem. Meanwhile, limited white noises are added at each stage of the EMD. Then, a unique residual component is computed to get each intrinsic mode function with a small number of ensemble size, thus, the mode mixing problem is solved. The results of the numerical simulation and real experiments show that the proposed method has good performance in solving the mode mixing problem and can restrain the end effect problem effectively.

Seismic exploration is the main method in oil and gas exploration. It becomes more and more difficult to identify the collected seismic signals, because of a sharp drop in resolution and the Signal to Noise Ratio (SNR). Conventional seismic record processing methods have shown no adaptability to very low SNR. In order to realize the requirement of high SNR, high resolution and high fidelity of seismic data processing in strong noise, this paper proposes a novel method of seismic data noise suppression based on similarity matched Wiener filtering. In this method, based on the local and non-local similarity of seismic events, the whole record is divided into overlapping sub-blocks and the blocks containing similar signals are found out by some distance measures. Then, the low rank matrix is constructed by Singular Value Decomposition (SVD) and the smaller singular values are removed representing noise. The noise in the constructed signal is effectively suppressed. Using this estimation, the Wiener filter is able to obtain a more accurate transfer function. At the same time, the effect of prior information on noise suppression is eliminated. Experiment results illustrate that the proposed method improves the SNR and effectively retains the signal amplitude.

The existing method of velocity optimization for surface monitoring only considers the velocity uncertainty of each layer, which bring certain errors in the results of perforation shot relocation. A new method of expanding the solution space on the basis of amplitude stacking is proposed to improve the accuracy of perforation shot localization. In the process of every fast simulated annealing, the velocity uncertainty and location uncertainty of each layer are considered simultaneously. Synthetic data test shows that, compared with the existing method, the proposed method can accurately locate the perforating shot to its actual value, and can effectively improve the location reliability of microseismic events near the perforation. This new method is applied to actual field data processing, and its validity and practicability are verified.

Regarding that the videos collected by intelligent monitoring system in coal mine underground are blur, a novel algorithm for unclear video object detection based on improved particle filter is proposed. In the framework of standard particle filter, a nonlinear, non-Gaussian and multi system state space fusion model is constructed based on frame difference. First, particle sampling and probability density propagation are realized in the region of the key points obtained in the frame difference image. Then, the weighted posterior sample particles are used to represent the posterior probability density of the multi system state space fusion model. The mean of the samples is used to estimate and fuse the posteriori state of the system. Finally, the system state space model is output to fulfill the object detection. Experiments are carried out using the video data of the Sanjiaohe coal mine underground monitoring system. The performance of the proposed model is evaluated by comparison with extended Kalman filter, unscented Kalman filter and particle filter. The improved accuracy and effectiveness of the proposed method are demonstrated.

In order to raise the whole count rate of a wedge-strip anode's photon-counting imaging detector, according to the feature of the signal output from the detector, a position readout circuit was designed and developed. This circuit is based on high speed Analog-Digital (A/D) converters and a Field Programmable Gate Array (FPGA) chip. The circuit employs high speed A/D converters with 65 MHz sapling rate to transform the Gaussian pulse analog signal into digital series at every clock period and obtain the peak value of the pulse signal by a FPGA. It has the functions of peak hold module of voltage pulse and NI data collection card in the original circuit. The FPGS processes the received digital series according to certain rules and sends them to the computer by UBS data interface. The developed software can compute the coordinate position of every photon and display them on PC screen according to obtained 3-way data. The design of the circuit hardware and logic control is described in detail in this paper. Experiment results show that the designed circuit can get a 2D image with same position resolution and double count rate compared with the original circuit with peak hold and NI card.

In order to improve the efficiency of hard formation drilling of coal mine, a design concept of new arc angle Polycrystalline Diamond Compact (PDC) drill bit is put forward by referring the design and processing concept of oil PDC bit. Taking Ø 113 mm arc angle PDC drill bit for example, the cutting structure and hydraulic structure of the PDC drill bit are designed using Finite Element Method (FEM). Simulation results show that, when the crown shape with inner cone angle 130° and outer taper arc radius 20 mm, the cutters with cutting angle -15° and inside angle 4°~ 6°, and using straight blade, the rock breaking efficiency of arc angle PDC drill bit is the best. In the same time, when the nozzle spray angle 22°~ 30°, and the azimuth angle working face near the cutter, the migration of cutting is the best. Based on the above research, ?113 mm arc angle PDC drill bit was produced. Field test shows that, the average bit life and drilling efficiency of the drill bit are 626 m and 25 m/h, respectively, which are increased by 4 times and one times compared with the ordinary concave PDC drill bit. Therefore, in the hard formation drilling process, the arc angle PDC drill bit can be used to improve drilling efficiency and reduce drilling cost.