A rigid multibody dynamic model was built for the heavy commercial vehicle cab air suspension system using the virtual prototype technique. The model was verified by the vehicle road test, and used to analyze the modal characteristics and the ride comfort of the vehicle. Taking the stiffness and the damp of the cab suspension components as test factors, the parameters of the cab suspension system were matched and optimized by means of the orthogonal test design technique. The simulation results indicate that the ride comfort in the cab can be improved by optimization of the cab suspension system parameters.

  A finite element model for the car body including doors and windows, a finite element model for the car interior acoustic field, and a coupled structureacoustic model were built and the car interior coupled acoustic field was predicted. A sensitivity analysis model was built for the car interior acoustic field, and the acoustic pressure sensctivities of the admittance of the acoustic field boundary and the board vibration velocity were studied. According to the sensitivity analysis results, the ribs and the thickness of the key boards were optimized, leading to reduction of the main peak values of the car interior acoustic pressure level by 2~3 dB(A).

     Based on analyzing the mechanism of switched reluctance motor/generator regenerative braking, a model was set up for the regenerative braking torque computing and energy reclaiming. A dual switched reluctance motors/generators regenerative braking scheme was designed for a frontwheeldrive vehicle, and its control strategy was developed. The hardwareinloop test was peformed on the vehiele regenerative braking test bench, and the results show that the energy reclaiming ratio in the dual motors/generators scheme is 10% higher than that in the single motor/generator scheme at low to middle braking intensities, and the larger the braking intensity, the higher the energy reclaiming ratio.

     Based on the investigation of the heat transfer of the energy diffusion and transport during the processes of the energy input, storage and extraction in the underground thermal energy storage(UTES) system, a new concept, the energy flux, was presented to evaluate the effect of the thermal energy storage. Through measuring the diffusion transport degree of storaged energy, the effect of energy flux in the UTES can be analyzed quantitatively, providing a measuring parameter and a basis for the heat diffusion control. Based on this, the energy fluxes of the underground heat exchanger group with different configurations and different multiborehole arrangements were studied to compare their difference on the energy flow intensity in the period of conserving energy stored in soil. The results show that the exchanger group configuration and the multiborehole arrangement determine the underground temperature distribution which plays an important role in the energy diffusion and transport during the processes of energy input, storage and extraction.

    Real time fuel consumption was experimentized in different urban roads and time of the city of Changchun by using the car fuel consumption real time testing system which was built for this research. The average fuel consumption model based on velocity during peak and flat period, the fuel consumption model which was based on velocity on different types of roads and the instantaneous fuel consumption model based on different velocity and acceleration were set up according to the experimental results. At last, the corresponding fuel consumption models were validated through other experiments. The results showed that the models can reflect the fuel consumption change of vehicle on the urban roads and provide an efficient way for accurately forecasting the states of vehicle fuel consumption on the different urban roads.

     To analyze the effects of driver fatigue on the driving safety, the sense, judgement and operation behavior of the driver were investigated by means of the experimental psychological test and the subjective fatigue investigation. The variation of driving behavior evaluation index at different fatigue degrees was analyzed and the threshold values of the index at different fatigue degrees were defined. The recommended maximum continuous driving time was proposed based on the driving behavior of driver to provide a reference for formulating or revising the regulation for the safe driving time of the automobile driver.

     To mimic the cuticles of some typical soil animals, series biomimetic nonsmooth surface specimens with different unit shapes, distributed spaces and slopping angles were prepared by laser processing. The wear behaviors of the specimens under dry sliding were investigated. The results indicate that the biomimetic nonsmooth surface specimens possess better wear resistance than the untreated specimens. The specimen with grid nonsmooth units has the best wear resistance, the specimen with stria units takes the second and that with convex units is the worst. The wear resistance is enhanced by reducing the distributed spaces of the nonsmooth units. The wear resistance of the stria nonsmooth specimen with slopping angle of 45° is better than those with slopping angles of 0° and 90° respectively. The adhesive wear is the dominative wear mechanism.

     The effects of addition of ultrafine CrFe powder in different contents on the tribological behavior of sintered steel were investigated. The morphology of worn surfaces and the tribological mechanism were analyzed by scanning electron microscope(SEM). The results show that addition of ultrafine CrFe powder improves the strength, hardness and wear resistance of sintered steel, and the wear resistance is best at Cr content of 1.5%. The SEM observations of the worn surface revealed that wear leads to the plastic deformation in a certain depth, and the higher the hardness, the thinner the deformation layer. In the early stage of the wear process, the abrasive wear is the dominant mechanism. Later, the dominant is the delamination wear resulted from the plastic deformation and leading to the crack of the subsurface.

     A perturbance method to analyze the process of stretchbending is introduced in this paper. For the convexoconvex workpiece with small curvature in across to the pull direction, it is divided into two areas, one is the area contacting the die surface and the other is the free area restricted on the one end by gripper jaws. Based on the assumption that the components of stressstrain state in the two areas are different from those in stretchbending over cylinder die and strip stretching by additional small values, the perturbed solution is build and the deformation is analyzed. Using the numerical simulation software, the stretchbending process of the roof curve beam of the stainless steel body of subway cars is studied and the technological parameters are optimized, the forming defect is eliminated and the stretchbending die with high precision is developed, and quality stainless steel parts are made finally.

      The viscoplastic behavior of the forging was studied, its elasticviscoplastic model was built and its constitutive relation was presented. Based on these a dynamic model was established for the hydraulic forging. The hammer hitting power was calculated, and the mathematical expression for the hammer formdation vibration was solved. The simulation research was performed and the results were verified by experiments. It was concluded that the established model can be used in the engineering design of the hydranlic forging hammer.

     To solve the problem of automatic blade grinding, a method for robotic blade grinding based on the reverse engineering was proposed. Scanned by a robotic reverse engineering system, the point data with the geometrical information of the blade profile was acquired. A CAD model of the blade was reconstructed by the reverse modeling technique, the isometric trajectory method was employed to proceed the path plan of robotic grinding, and generate the robotic grinding trajectory. The robotic blade grinding experiments were carried out by the generated trajectory to prove the proposed method effective and feasible.

    A new calculation method was suggested based on the numerical solutions of the 3dimensional flow field to calculate accurately the axial force in the hydrodynamic torque converter(HTC). The 3dimensional flow control equations were solved numerically by means of a computational fluid dynamics(CFD) software, and on the basis of the obtained numerical solutions of the flow velocity field and the flow pressure field in the HTC, the axial force can be derived. An application case of the new method was demonstrated, and the obtained axial force was compared with that from the traditional method based on the 1dimensional flow theory and the experimental result. The error of the result from the new method against the experimental result is less than the traditional one.

     The static and dynamic characteristics of the pneumatic proportional flowrate control valve were studied. It was found that the variation of the critical pressure ratio versus the valve opening is nonlinear, it increases at first and then decreases, and the ratio ranges from 0.17 to 0.38. The discharge coefficient was calculated with the help of Sanville flow formula by measuring the flowrate through the valve at different openings, and the coefficient ranges from 0.55 to 0.77. The relationship between the discharge coefficient and the valve opening was found nonlinear also. The frequency response of the valve was acquired by the sine sweep exitation and the spool position measurement. The results show that the bandwidth of the valve decreases with the increase of the input signal amplitude, and the supply gas pressure has no effect on its bandwidth. The heat transfer processes between gas in the cylinder and the cylinder wall, as well as between the cylinder wall and the environment were described using a lumped parameter mathematical model. A differential equation of the gas temperature was deduced and a thermodynamic model of incylinder gas was established. The simulation and experiment of the pneumatic servo system were performed and the simulation results agree well with the experiment ones.

    A walking device driven by piezoelectric patches was developed which moves forward by the slight partial elliptical movement of its feet soles. The walking mechanism of the device was analyzed and 3 experimental devices with different vibration angles were made. The effects of the voltage and the frequency of the driving power supply as well as the vibration angle on the movement behavior of the walking device were investigated experimentally. It was found that the device can walk in sliding, jumping and inversing.

    The uncertainty of routing and processing time, the machine failure rate and the maintenance rate are 3 major stochastic factors affecting the stability of the remanufacturing system. Considering the effects of these stochastic factors, a time buffer model was built for the remanufacturing based on the drumbufferrope(DBR) technique. Taking the endoflife automobile engine as an example, combining the modelling and computer simulation, a complete remanufactruing time buffer control mechanism was established based on DBR to solve the uncertainties existed in the remanufacturing system. The simulation results show that the developed time buffer control mechanism improves the resource utilization of the bottle neck operation, cuts the average work in process(WIP) upstream the bottleneck and the total WIP, enhances the output rate of the system.

    Considering that the productivity of the manufacturing enterprise of largescale power generation equipment is decided by its large critical machining equipment, an optimization model of the top layer of its hierarchical planning mode is proposed. A genetic algorithm called XYGA is developed to obtain the solution of the model, which has an extra Y chromosome to deal with the source flexibility. To overcome the low efficiency of the accurate fitness evaluation procedure of the genetic algorithm in solving large scale problem, a fast fitness estimation method based on similarity between parent and child is introduced to improve the convergence speed of XYGA. Simulation experiments show that the proposed algorithm, named FXYGA, can save the solution time by 50%～70%, meanwhile the solution is satisfactory.

    An entropy weight method with objective weighting was used to evaluate the reliability of the numericallycontrolled machine tool. The method avoids the shortcoming of the weighted comprehensive evaluation method which lies in the subjectivity in weight determination. Based on the built comprehensive evaluation indicator system(mean time to first failure MTTFF, mean time between failures MTBF, equivalent failure rate D) and the reliablility data from the 2 types of machining center, the weights of indicators were calculated and the comprehensive evaluation on the reliability of the machining centers was performed.

    A new type device for seedling tray continuous feed and synchronous cavehole alignment was developed for a precision seedling transplanter using the combination of an electromagnetic directional valve and a pneumatic cylinder. A twolayer tray feed mechanism accomplishes the tray feed in turn pneumatically. The synchronous alignment of the tray feed is controlled by a position limitation cylinder. The accurate alignment of the tray cave and the pneumatic cylinder seedling sucking hole was realized by releasing the tray after receiving the cavehole alignment signal. Experiment results proved that adopting the twolayer tray feed and synchronous alignment device reduces the laboring intensity effectively, ensures the orientation precision of throwing seedling, improves the seedling transplonting quality, providing a reference for the development of the technology and equipment of paddy precision seedling transplanting.

ased on the effects of liquid bridges formed by the capillary water on the micromechanical structure of soil, a nonlinear mechanical model of contact between soil particles was established by introducing parallel bonds which can represent the cohesive actions of liquid bridges between soil particles. The dynamic disturbed behavior of soil, which was subject to the bulldozing plate with a complex wavy surface, were simulated by discrete element method (DEM) from the macroscopic and the mesoscopic aspects. The DEM simulations reappear the qualitative and the quantitative results by laboratory test accurately. Moreover, from the mesocopic analyses by DEM, including the soil particle motion and the soil clump fracture, the influencing factors and the mechanism on the dynamic behavior resulted from the complex surface of the soiltouching part were given accurately.

    Apple pomace was used as raw material to extract pectin by the highintensity pulsed electric fields. The optimal processing conditions were acquired by the singlefactor experiments and the orthogonal experiment. The most yield rate 14.12% by pectin was achieved under the following conditions:electric field intensity 15 kV/cm, pH  value 3, electric pulse number 10, stuffliquid ratio 1∶19 and temperature 62 ℃. The comparative extraction tests were performed by the acid extraction method, the ammonium oxalate method, the ultrasonic extraction method, and the microwave extraction method, and it was found that the highintensity pulsed electric field method is the most effective method to extract pectin from apple pomace.

Waste brewing yeast protein was hydrolyzed by dispase and measured by the degree of hydrolysis. Orthogonal design of linear regression was adopted to obtain regression equation. The optimal conditions are calculated as: concentration of waste brewing yeast protein 1.13% , concentration of dispase 5.02%, temperature 54.3 ℃, pH 6.1. Three time tests verify that the degree of hydrolysis is above 44.71%. The results indicate that the regression equation is of great significance to industrial production.

    A coupling thermal stress finite element model is proposed to investigate the physical phenomenon that the surface pits can improve the thermal performance of pistonliner. First, nonlinear analysis is carried out on the contact problem, and the contact force and the friction work are obtained. This friction work is then converted into thermal energy as a surface heat flux, which is taken as the boundary condition of the governing equations of temperature field, thus, the coupling between stress field and temperature field is achieved. Simulation was conducted and results show that the maximum temperature on the piston surface with pits is locally higher than that of smooth piston surface, but the overall temperature distribution is uniform. One of the main reasons for local wear of smooth piston skirt is due to the temperature focus which can induce poor heat conduction. The pits can disperse the heat of the piston skirt that avoids the wear and hightemperature adhesion. Therefore, the surface pits can enhance the wear resistance of the piston skirt and prolong the service life of pistons.

     To solve the problem that the state of flexible payload handling is not completely measurable, the control of manipulators handling a flexible payload based on output feedback is studied. The cooperative system is decoupled into a quick subsystem and a slow subsystem by singular perturbation theory because that the inputs are less than the degrees of freedom. The relations between the vibration states of the system are established using the information of points between the ends manipulators and the flexible payload and the characteristics of the flexible payload, and the observer is designed. The error equation of the observer is transformed into state matrix according to the characteristics of the system. The parameters of the observer are designed using the eigenvalues of the matrix, and this idea is used to prove the stability of the system. Simulation results validate the designed observer and controller.

   For uncertain TS fuzzy systems with normbounded uncertainty and timedomain constraints, including control input constraints and state constraints, a robust optimal control scheme is proposed. The sufficient conditions for seeking state feedback gains are derived using SProcesure method. The design problem is then lead to solve an optimization problem with the constraints of a set of nonlinear matrix inequalities. An iterative algorithm for the solution of the problem is presented. Simulation is carried out for an inverted pendulum system and the results demonstrate the effectiveness of the proposed scheme.

    Aiming at the fast response of the motor speed in the hybrid electric vehicle, a mathematical model was constructed for the permanent magnet synchronous doublerotor /doublestator machine on the basis of analyzing the traditional mathematical model of permanent magnet synchronous machine. A fuzzy controller of rotor speed was designed by means of the fuzzy control method of artificial intelligence. Simulation results by MATLAB demonstrate that the fuzzy control method of rotor speed is better than the traditional one. It is characterized by fast response and small oscillation. The results are of great significance to develop the control system of the permanent magnet synchronous doublerotor /doublestator machine in the hybrid electric vehicle.

      The status of gradient projection method of redundant manipulator is analysed, the effect and selection methods of the scale factor of the homogeneous solution is expatiated. A new method to calculate the scale factor is proposed which will make it changed continuously in real time. Computer simulation has been conducted to compare the new scheme with the other two typical ones, the results show that the new algorithm with the continuous scale factor can make the joints angle, joints velocity and joints acceleration of the manipulator more smoothly and continuously, it also can overcome the shortcoming of two traditional gradient projection methods. Experiment results with a 4 DOF manipulator verify the validity of the proposed algorithm.

    Adaptive tuning methods for digital camera parameters are proposed to increase the robustness of machine vision system under various illuminations. Camera parameters are online estimated first; then, analog to digital conversion level, gain, black level and exposure time are tuned according to the environmental illumination to guarantee that the average intensity of binary image is within a predetermined range. Experiments demonstrate that the method of adaptive tuning is helpful to capture canonical images in a large scale of illumination variation. The proposed method can weaken most influences of various illuminations on the machine vision system. The precision of subsequent position measurement is improved and automatic running of the machine vision system is guaranteed under various illuminations.

   To investigate the disease spreading behavior within population of mobile individuals, the SusceptibleInfectiveRemoved (SIR) epidemic model is embedded into the individual motion model based on two dimensional (2D) regular lattices. Meanfield theory and largescale numerical simulations are employed to analyze the critical threshold of the SIR model. The results indicate that the effective critical propagation rate is closely related with the density of mobile individuals, and the motion also remarkably influences the epidemic spreading behavior. At the end, some feasible control strategies, which are based on the analytical and simulation results, are proposed to contain the epidemic spreading within mobile populations.

    An engineering oriented online identification technique for a twoinput and twooutput(TITO) closedloop control system was presented. By two setpoint change tests, the frequency response in the range of interest corresponding to   phase lag were estimated, and the parameters of transfer function matrix were identified by matching the model in the frequency domain. The proposed identification method only requires response data of process input and output, and no prior knowledge of the process dynamics is needed. The typical TITO processes were employed to illustrate the effectiveness and practicability of proposed method.

     The features of Surface Nuclear Magnetic Resonance (SNMR) signal for underground water and the sources and characters of the spike noise distortion are analyzed. A method to eliminate the spike noise interference is proposed and program simulation is conducted. Three improved noise elimination methods based on stacking method are compared by simulation. It is shown that the Dvalue thresholdvalue substitution stacking method outperforms the other methods in terms of spike noise suppression and SNMR parameters extraction. Largescale field measurements demonstrate the feasibility and practicability of the proposed spike noise elimination method. High Signal to Noise Ratio (SNR) and low noise signal are achieved and accurate parameters are obtained for the SNMR conversion.

    According to the denoising theory based on the nonlinear diffusion equation, the nonlinear diffusion equation was applied to denoising of electrical derivative data of semiconductor laser diode (LD). Comparing with the denoising method based on mean value filtering, the experiment results indicated that this denoising method can reduce the noise in electrical derivative data of LD more effectively, and moreover the dip height of the electrical derivative curve at the threshold current can be preserved. The errors in parameters obtained from the measured electrical derivative curve were reduced too. The quality and reliability of LD can be estimated effectively using parameters from the measured electrical derivative curve after being denoised.

    According to the characteristics of directed line objects, such as track, a detailed topological relation model is proposed, thus the complex details can be captured. First, DLO matrix is defined based on the 4intersection method of spatial reasoning. Then, by apply the intersection types to DLO, the DDLO model with rich spatial semantics is obtained. Finally, the analysis and comparison with classical models (HBT etc.) show that DDLO can precisely describe the detailed intersection of directed line objects and distinguish intersection and tangency, while HBT can only distinguish fixed 68 simple relations.

     The motivation to integrate ontology layer with rule layer is to improve the features of knowledge presentation formalism, named the expressive power and the reasoning procedure of semantic web. Also the integration is not just simply unifying conclusions derived from each layer. In addition, when the expressive power is increased, problems will arise from reasoning. In this paper, we introduce an integrated knowledge representation formalism and an algorithm for reasoning on this formalism. A varietal approach, named ModelTableau, is proposed, which is based on tableau calculus. This approach can be used to deal with expressive representation and complex reasoning under combing ontologies and rules. Furthermore, the reasoning algorithm is given that combines the ModelTableau approach and the Topdown procedure based on SLDResolution. The soundness of this algorithm is proved and a prototype system is provided. The results show that both the expressive power and reasoning procedure are improved.

    An improved clonal selection algorithm for protein contact map prediction is proposed. The fitness function of the algorithm is constructed by using the protein folding restrictions, such as the hydrophobicity of amino acids, the secondary structure inclination of residues, the total number of contacts in contact map, and so on. Variance operation according with the biological properties of the contact map is designed. This algorithm does not need additional proteins as the training set to extract the template; therefore it is not affected by the existing limitations of protein structure. Prediction tests for 200 nonhomological proteins with different lengths are conducted and the results verify the effectiveness of the algorithm.

     In order to prove that the fixedpoint arithmetic specification is equivalence to the translated Register Transfer Level (RTL) implementation, the fixedpoint datapaths, which perform ADD, MULT and SHIFT operations, are modeled by combining arithmetic transform (AT) and polynomial function. According to the results of polynomial function, the upper bound of simulated vectors is obtained for the equivalence verification of the fixedpoint datapaths, which avoids the exhaustive simulation. Experiment results show that the proposed method is effective.

    According to the expansion of data storage, a method of anomaly detection based on Fusion Principal Component Match (FPCM) is presented. First, the isolated points in the subnode data are removed and the stability of the principal component analysis is enhanced by clustering. Then the clustering center is transmitted to a center node, which can reduce the traffic of data between nodes and achieve the fusion principal components. The normal behavior model established by the conversion matrix of the principal component cluster centers can embody the characteristics of the overall data. Finally, the decision tree method is used to accelerate the matching speed. Experiment results show that the FPCM method can maintain a high detection rate of DOS, an overall detection rate of 97% is obtained; meanwhile, the false positives is controlled below 10%. The detection rate of this method is equal to that of the existing methods.

      During message exchange in acrossapplication there is risk of security certificate. An authorization management model based on Security Assertion Markup Language (SAML) and Privilege Management Infrastructure (PMI) is presented in this paper. The model implements authority management and grants access through combination of logic separation and application. It uses SAML assertion, SAML protocol and SAML binding technologies to conduct identification, attribute acquisition and grant decision based on PMI. This model attains the ability of certificate management by the Attribute Authority (AA) and the Lightweight Directory Access Protocol (LDAP). Experiment results demonstrate that the model is competent for acrossapplication security access control of multirole users.

     An approach to extract news contents automatically from news web pages is proposed. Compared with existing methods, this approach can determine whether a web page contains news content first, then extract the news contents without using DOMTree or template. A new concept of Block is introduced and by one traversal the approach partitions web page into main content block and noise block. Further more, the concept of Web Page Block Distribution is introduced and the features of Block Distribution are investigated. The use of Block Distribution can effectively determine whether a web page contains news contents. Experiments show the approach is effective in extraction of news contents.

 A high level data flow synthesis method with low power based on Horner form is presented. Using Horner form the function description of the circuit is transformed to get the final polynomial form. The dataflow is scheduled, allocated and bound based on Horner form. During the process of synthesis the influences of binding and layout on the length of interconnect wire are considered, and the power consumption is reduced by shortening the wire length. By this method better circuit design can be obtained in limited area to satisfy the performance requirement. Experiment results demonstrate the efficiency of this synthesis method that the power consumption is saved by about 20% compared with existing synthesis method.

     A novel traffic sampling measurement method in highspeed IPv6 networks is proposed. The method is to sample IPv6 traffic based on the information entropy theory. Firstly, we present a distributed IPv6 network sampling measurement framework including communication and sampling modules. Secondly, through computing the bit entropy in real IPv6 traffic traces, we discuss the randomicity of each byte in IPv6 packet headers, and select those bytes having a good randomicity as the input of our traffic sampling method. Finally, an experiment is performed to prove that the output of our method has sufficiently uniform and the sample's curve of cumulative distribution function of packet size is fully conformed to the parent's.

    It is difficult to segment SAR image because of the speckle noise. The traditional segmentation method of finite mixture model has been adopted extensively in SAR image segmentation. However, both the performance and the robustness are not good enough. A nonparametric Bayesian infinite mixture model, called Dirichlet Process Mixture Model (DPMM) clustering method is proposed to segment SAR image. The proposed model can simulate the intrinsic property of SAR image and the segmentation method can determine the number of clusters automatically. Experiments on both simulated data and real data are carried out. The results verify the effectiveness and robustness of the proposed method in comparison with the traditional methods.

    In order to satisfy users' request of high QualityofService (QoS) and reduce algorithm complexity, an adaptive resource allocation algorithm for multiuser OFDM system based on QoS is proposed. In this algorithm, subcarrier and power allocation are carried out sequentially and a subcarrier allocation method based on QoS is derived. The users are classified into VIP users and normal users, and different power allocation algorithms are applied to different users to make the MUOFDM system to be a service quality guaranteed system. Simulation results demonstrate that the proposed algorithm can ensure the performance for both VIP user and normal users, and the overall complexity of the algorithm is lower.

    This paper presents a parameter estimation method for weak sinusoidal signal embedded in chaotic noise. This method is based on error feedback synchronization, in which only one driving variable passing through a filter is used. First, the filtered mixed signals (chaotic signal, white noise and sinusoidal signal) are used to drive a new response chaotic system, which is the same with the driving system. If chaotic synchronization occurs, there exists sinusoidal component in the error data series between driving and response signals. The crossspectral MUSIC method is used to estimate the sinusoidal frequency in the error data. This method is suitable for the situation where the interference signals are the mixture of strong chaotic signals and white noises. Simulation results show that the proposed method is simple and effective.

    After the investigation of the existing Baton Handover (BH) algorithms in cellular networks, a new BH algorithm in the Time Division Synchronous Code Division Multiple Access (TDSCDMA) system is developed, which is called resource reservation based preferential queuing scheme with selfadaptive threshold. Simulation results show that this algorithm improves the PRI of VIP and high rate users. When the call rate of handover is higher, the division of users can improve the QoS of the system and the efficiency of the total channel utilization. The BH lost rate by the new method is reduced by 50% compared with the PRI method. The advantage of this new method is more obvious as the user move rate is high.

     A method named folded linear approaching is proposed to reduce the delay of Turbo decoder system, meanwhile, still ensures excellent low bit rates. This approach is able to maintain fast system operation and good decoding capability by only using competitors and adders. Simulation results show that the decoding performance of the method is much better than that of MaxLogMAP, and can reduce systematical delay by 1.5 times than the square method.

    The congestion problem due to contending for the shared wireless in multihop Ad hoc networks is investigated. Then a novel ReceiverBased Adaptive Backoff (RBAB) algorithm is proposed. In this algorithm, the sender adjusts its contention window according to the feedback of receiver's congestion level, changes the nodes' channelcontending ability and packet sending rate on the whole, thus, achieves the control of the congestion problem. Simulation results show that the RBAB algorithm can remarkably increase the network saturation throughput and effectively control the network congestion in the Medium Access Control (MAC) layer.

     A new synchronization scheme based on energy capture for UltraWideband (UWB) systems is proposed. With the help of judicious training symbols and symbollevel samples, the energy values of the truncated tail and head of the received symbol waveform can be obtained. Then according to the two energy values the framelevel timing acquisition is acquired. It is worth noting that with perfect knowledge of the multipath channel, the proposed scheme can achieve timing synchronization at any desirable resolution. In addition, the proposed algorithm only exploits symbollevel samples without complex searching process, thus it turns out to not only speed up the synchronization, but also enjoys lowcomplexity. Simulations and comparison confirm that the proposed algorithm outperforms existing alternatives in terms of normalized mean square error and bit error rate.

    In traditional methods, when the relative motion between video objects in consecutive instants was complex, only the spatial shape error concealment was used with not very desirable effect. In order to obtain better concealment results, a Temporal shape error concealment scheme Robust to Rotation and Translation (TRRT) is proposed. This scheme is based on the invariant properties of rotation and translation of both Harris interest point detector and local Zernike moments. First, the best matching pairs of interest points are obtained by comparing the Euclidean distance of local Zernike moments defined on the neighborhood of the interest point. Then, the global motion parameters between video objects are determined and motion compensation is given to the reference boundary. Finally, the missing boundary pieces are reconstructed by boundary matching and compensation. This new scheme is compared with traditional temporal and spatial methods. Results show that better concealment can be obtained by this new scheme.

    A multifocus image fusion algorithm based on directional windows statistics in nonsubsampled contourlet domain is developed. First, source images are decomposed to the domains of nonsubsampled contourlet transform. Then, the image fusion is implemented in subbands with different scales and directions combining with regional statistics. Regional variance and local energy are adopted as the fusion rules in lowpass and highpass subbands, respectively. Finally, the fused image is obtained through inverse transform. Experimental results show that the directional windows in nonsubsampled contourlet can detect the image features more effectively and the fused image has better subjective visual effect. Comparison indicates that the proposed algorithm outperforms the traditional gradient pyramid algorithm and the wavelet based algorithm in terms of the fusion quality index.

   To solve the problem of feature extraction in image registration, an automatic method to extract landmark points for elastic medical image registration is proposed. First, a new similarity measure, named as arithmetic harmonic mean divergence measure (AHM), is induced. The reference image and floating image are rigidly registered by AHM measure. Then, the two images are divided into uniform blocks. The landmarks in object are extracted by regional rigid registration by maximizing AHM measure between the corresponding subimages. According to corresponding landmarks, the global elastic registration is achieved by bicubic Bspline functions. Experiments on registration of brain Magnetic Resonance (MR) images and Computed Tomography (CT) images show that the proposed method is accurate and fast.

   In this paper a more precise collision monitoring method is proposed first, which takes the influences of the shape of satellite, predict time, relative covariance matrix and all kinds of perturbations into consideration. Then, because it is very difficult to predict the error of along track position, a conservative autonomous safety operational method based on the judgment of the collision probability in the projected XZ plane is presented. Finally, the proposed collision monitoring algorithm is used to analyze the passive operational safety of Direct Satellite System (DSS), and a new formation geometry design method is proposed. By using this new design method the DSS can have good passive operational safety.

    A new mathematical model based on optical measurement and screenspot images is proposed, which can be used to the measurement of aircraft attitude parameters. First, the highspeed cameras and the fixed screens on the test site are calibrated using laser tracker; the conversion relationships between various coordinate systems are established. Then, the laser cooperation object, fixed on the surface of aircraft, projects the laser beams on the screens, and the cameras synchronously record the positions of lightspots. The lightspots change with the aircraft attitude; hence the sequences of the recorded images can be used to calculate the attitude parameters of aircraft. The error sources of this model are analyzed and its measurement accuracy is estimated using Monte Carlo simulation. Experiment results show that the measurement error of each attitude obeys normal distribution approximately, which is no lager than 3′ when the rotation angles of the three axes are within certain ranges.

   This paper studies the impulsive station keeping strategy for libration point missions. First, the dynamic model is given and the nominal orbit is calculated. Then, the impulsive station keeping strategy is analyzed and the standard impulse for station keeping is discussed. Finally, statistical results are obtained by Monte Carlo simulation, in which the effects of injection errors, the navigation errors and the maneuver errors are taken into consideration. Under the conditions that the minimal maneuver interval is 30 days and the minimal maneuver velocity is 0.02m/s, it is obtained that to keep the station for four years, the consumed maneuver velocity increment is 0.44m/s in average and the average maneuver interval is 71.5 days. Higher maneuver velocity increment is required when standard impulse is introduced and the increment of the consumed maneuver velocity increases with the amplitude of the standard impulse and the minimal maneuver interval.