A real-time recognition strategy was proposed for driving wheel ship rate of the vehicle with motorized wheels corresponding the adhesion limit based on the adhesion behavior between the vehicle tire and the road surface as well as the features of independent driving of motorized wheel system. The adhesion characteristic between the tire and the road was expressed by the wheel dynamic parameters  including the driving torque and speed of wheels. The wheel slip was detected real-timely by computing the derivative variation of the adhesion factor and the optimal slip rate corresponding the adhesion limit was recognized. The proposed recognition strategy was verified by simulation and real vehicle test on road. The results show the strategy can judge accurately whether the wheel slips and give out the optimal slip rate and the adhesion factor limit.

Aiming at the need of the vehicle equipped with the continuously variable transmission for both power performance and fuel economy under non-steady working conditions and the fact that the present control strategy is lack of accurate target of transmission ratio control, taking the best match of power performance and fuel economy as control target, an optimal matching datasheet control strategy was proposed. Based on the experimental data, a driveline model was built with MATLAB/Simulink. The relationships between the fuel economy and the target transmission ratio under non-steady working condition were determined by simulations, the best matching datasheet was obtained by matching with the power performance, and the optimal control target on transmission ratio was achieved. Simulations under typical non-steady working conditions show that the optimal matching datasheet control give out accurate optimal transmission ratios.

A multistage control algorithm was developed for the dry dual clutch transmission(DCT) system based on the dSPACE rapid control prototyping. The algorithm is completed in the Simulink/Stateflow environment, and realized by the Real-Time Workshop in hardware. The rapid control prototyping accelerates the design, execution, test and realization in the real hardware, and shortens the development cycle. Downloading the algorithm into a DCT transmission control unit to perform the platform test, the correctness of the algorithm was proved by the comparison with the hardwareintheloop simulation platform of the rapid control prototyping. The developed control system has been applied in the dry DCT design.

Considering that the heavy-duty commercial vehicle(HCV) is vulnerable to rollover because of its high masscenter and bulky dimension, a HCV rollover warning algorithm was developed based on the rollover time prediction. The algorithm was derived from the built simplified HCV rollover warning model and the determination of dynamic rollover threshold. A real-time rollover warning controller to perceive the rollover risk in dangerous conditions was developed and verified by in-situ vehicle tests. The test results show that the derived warning algorithm worked well in the developed controller, it was capable of reminding the driver to take measures timely to avoid vehicle rollover at its approaching.

Excessive vibration in commercial vehicles due to excitation from road irregularities leads to ride discomfort and safety trouble. A threedimensional finite element model was built for the full vehicle to study the effect of frame stiffness on ride comfort of the commercial vehicle. The algorithms were given for the power spectrum density(PSD) and the rootmeansquare(RMS) of the accerleration response. The PSD and RMS of the vertical accerleration at the mid-point of cab floor for the two frames with different stiffness values under four excitations. The computed results show that when the frame stiffness increases, the RMS values of the cab vibration accerleration decreases significantly at the frequency band 14~26 Hz, and the driver ride comfort improves effectively.

The unsteady flow field around a minivan and the aerodynamic noise from its side window region were computed using the commercial computational fluid dynamics software StarCD.  The distribution of flow separation areas and the positions of aerodynamic noise sources were obtained using the steady Reynolds averaged NavierStokes method.  The unsteady characteristics of the flow field were analyzed using the detached eddy simulation method.  And the aerodynamic noise sound pressure levels at the monitoring points of the side window region were computed using computational aeroacoustics method.  The numerical simulation method was verified by the particle image velocimetry experimental results.  The main reasons to generate the aerodynamic noise were explained by the unsteady flow separating phenomena and the features of the vortex structure.  Numerical simulation results will be conducive to reduce the aerodynamic noise at the early stages of the automobile design process.

According to the calculation theory of the coupling loss factor(CLF) of the straight-line junction, the calculation formulas were deduced for the CLFs of the broken-line junction, arc junction and arbitrary curve junction. Models were established by numerical simulation for the coupling systems of the straightline junction, the broken-line junction, the arc junction and the arbitrary curve junction,and the CLFs were computed for these 4 kinds of junction. A statistical energy analysis(SEA) model was built for a car, the adjacent subsystems of the car SEA model were coupled, and the CLF of the line junction between subsystems of the car were calculated.

The dynamics of wheel-soil interaction, the tractive performance and the soil transformation and failure beneath the lunar rover vehicle wheel were studied by means of the soilbin lab test combined with the particle flow simulation. A lunar soil simulant was prepared by volcanic eruption material in Jilin province, China. A tractive performance test bed for deepspace rover wheel was designed and manufactured. The tractive performance tests were performed for the wheels with different lug types and the basic test data were obtained. The lunar soil failure by turbulence, the distribution of the contact force in soil and the variation of particle velocity vectors beneath the wheel of lunar rover vehicle under the gravitational field on earth were analyzed by the particle flow code taking into account of the discrete characters of lunar soil such as loose structure, fine particle size and strong mobility. The obtained tractive characteristic parameters of the wheel were compared with the soilbin test data. Furtharmore, the tractive performance of the rover wheel on moon surface was predicted.

An algorithm was proposed based on KMAS sheet forming analysis platform to simulate the trimming spring back in the thin sheet forming by the finite element method. The mesh relocation in the trimming region was achieved by the selfadaptive template of trimmed element. The deformation field data mapping from the old to the new mesh was realized by interpolation of the shape fuction. A simplified linear elastic unloading model was built based on the static implicit algorithm to predict the effect of trimming spring back. The numerical simulation on the international standard test part, an automotive underbody stretch crossmember, which was prorided by NUMISHEET 2005, was in good agreement with experimental result,validating the effectiveness of the presented algorithm.

To reduce the impact of engine vibration during start process on the vehicle ride comfort, which is important in particular when the startstop control strategy is applied in the engine, the vibration signals of the first cycle during start of engine were measured, and the effects of the initial position of piston, the cooling liquid temperature and the cranking speed on starting vibration were investigated on a Jetta 1.6 L gasoline engine. The results show that when the piston stays initially at the position near the top dead center after the intake valve closing, engine starting vibration is relatively weak. The vibration at warm starting(corresponding cooling liquid temperature 85 ℃)is weaker than that at cold starting(20 ℃).The cranking speed makes a notable impact on the starting vibration of the engine, rapid cranking makes much weaker vibration than original basic engine slow cranking does.

The effects of exhaust gas recirculation(EGR) and excess air ratio(a) on engine performance were investigated experimentally on a modified turbocharged and intercooled spark-ignition natural gas engine. The results show that the lean mixture combustion combined with EGR resulted in higher thermal efficiency than that only using lean combustion strategy at the same NOx emission target. Therefore, an EGR and a combined NOx  emission control strategy was proposed. The NOx  emission control domains at engine speed 2800 min/r,75% and 50% loads were deterrnied in which the NOx  emission kept below 1 g·(kW·h)-1 without need for exhaust gas after treatment and serious penalty on fuel economy.

The characteristics of particulate emissions from gasoline vehicles complying to Euro 3 or Euro 4 emission standards with port fuel injection(PFI) engine or gasoline direct injection(GDI) engine were investigated under cold start and hot start conditions by means of an electrical lowpressure impactor(ELPI) and an exhaust emission measuring system for the lightduty vehicle on a chassis dynamometer. The results show that the particulates emission from a Euro 3 PFI gasoline vehicle at cold start is characterized by higher particle number concentration and larger particle size, and that from a Euro 4 GDI vehicle is characterized by the highest particle area and mass concentrations. The particle number concentrations exhausted from both vehicles are in the same magnitude order of 106, and the particulates emission at hot start condition is 40% lower than that at cold start condition. More than 90% of the particle size concentration is distributed in the size range of 0.007~0.378 μm, more than 90% of the particle area concentration in the range of 0.055~9.83 μm, and 99% of the particle mass concentration in the range of 0.091~9.83 μm. Both the results calculated by ELPI and measured by particulate measuring system show that the particulates mass emissions from PFI gasoline vehicle under EUDC driving cycle are higher than those under ECE driving cycle. Results also show the particulates mass calculated by ELPI is different from that measured by standard measuring system.

To measure the combustion and emission characteristics of the boiler using the pelletized biomass fuel, a boiler combustion simulation test-bed was built. Experiments were performed with the test bed about the effects of different ratios between the primary and secondary air flow rates, and their supply positions, as well as the fuel layer thickness on the combustion performance and emission behavior, providing credible informations for the design of pellet biomass boiler.The test operation and practical trial of the prototype show that this kind of boiler is characterized by high efficiency, fuel saving, clean combustion and low air pollution, opening up broad prospects for its pratical application.

The relationships between the heat transfer behavior and the flow pattern, the temperature difference, the pressure droprin a Cu-base micro-channel heat sink with water coolant were investigated under low Reynolds number 34~191 with a developed micro-channel flow pattern visualization test system. It was found through visualized observation, the main flow pattern is an annular flow with the periodic oscillation appeares when higher heat flux density is supplied. The liquid flow rate decreases rapidly to zero when dry-up happens in the micro-channels. Under low entrance Reynolds number, it was revealed for the first time that the axial temperature distribution on the bottom of micro-channel heat sink presents lower temperature in the middle of sink substrate and higher in the both sides. It may be due to that the heat transfer coefficient is higher in the area where the flow pattern is the completely boiling annular flow. The pressure drop increases with the increase of Reynolds number and the heat flux density. Analysis shows that the flow pattern is the dominant factor affecting the heat transfer behavior of the Cu-water micro-channel heat sink.

Aiming at the shortcoming of the current methods of estimation of individual floating vehicle travel-time on roadsection, a new method based on the global positioning system(GPS) data and analysis of vehicle running characteristics was proposed. The vehicle travel-time estimation was improved in three respects. In the map matching module, the GPS point near the mode was matched jointly by the adjacent point GPS data to improve the map matching efficiency. Aiming at the different running characteristics of the floating vehicle across the road-section boundary point under different situations the time of vehicle passing the boundary point was processed correspondingly to raise the estimation accuracy of the boundary point passing time. The phenomenon of individual vehicle temporary stop by interference was analyzed and the interferential stop was removed effectively, and the effect of the individual vehicle behavior on the accuracy of estimation result was reduced. The method was verified by the experimental taxi GPS data and the result was encouraging.

According to the problem of lack of systematic and overall studies on traffic information collection methods based on GPS equipped floating car at present, which leads to a large number of basic data wasted, the low quality output traffic data, the high cost of system etc, the key technologies of traffic information collection based on GPS equipped floating car are put forward, and the functions of the key technologies are indicated, and the key technologies are studied deeply. The key technologies are verified with measured GPS data which collected on the part road network of Changchun, China. The results show that the key technologies and algorithms put forward above have obvious effects for solving problems, which will improve application effects of the road traffic conditions identification and vehicle dynamic navigation systems.

The domestic harzardous goods transportation accidents in 2008,China, were analyzed statistically to improve the safety and decrease the accidents of road hazardous goods transportation. The results showed that the management defect is the basic cause leading to accident, so it is urgent to strengthen the safety supervision system. A safety supervision system tree was established for the hazardous goods transportation from the analysis of structure of supervision system. The impact degrees of supervision factors on the construction of supervision system were derived from the calculation of the minimum cut sets and the structure importance level, so the major affecting factors were found, that is the technical application of supervision platform, the formulation of laws and regulations as well as the personnel quality. Obtained results provide suggestions for establishing a sciencetechnology supported safety superivision system for the hazardous goods transportation.

To evaluate scientifically the road traffic safety level(RTSL) in provincial regions of China, 10 evaluation indexes and a corresponding comprehensive evaluation method were proposed. According to the road traffic accident data in China mainland in 2005, the weights of 5 evaluation indexes were determined by discrepancydriven theory. The RTSLs in 31 provinces, autonomous regions and municipaties directly under the Central Government, China, were evaluated by proposed method. The results show that the difference of the RTSL between the provincial regions,China, is pretty large, and those in the eastern regions are better than the western. It is obvious that the RTSL does not harmonize with the local social-economical development in some western provinces and regions, especially such as Tibet and Qinghai. The harmony between the RTSL and local social-economical development is an important indicator to characterize the local road traffic safety situation.

Simplifying the flange of T simple-supported beam as the plane stress plate, an expression in closed polynomial form was derived based on the method of symplectic elasticity for the effective width of the T simple-supported beam under uniform or linear load acting on whole span. The solution of the effective width ratio from the expression under the uniform load was compared with the data in British Standard BS5400 and the result show that the obtained expression is correct, simple and effective, enriches the theoretical analysis and simplified calculation of the effective width in the T simple-supported beam bridge.

Provided that the road surface roughness(RSR) presents the fractal behavior such as the selfsimilarity, the scaling invariance, etc.,a RSR reconstruction model was built using the ideal fractal curve to simulate the RSR. The measured RSR fractal dimension was calculated by the power spectrum method. The average power spectrum character of the ideal fractal curve was analyzed and its relationship with the RSR power spectrum was established. Based on it a method was suggested to describe the statistical characteristics of the RSR using two parameters, i.e.the fractal dimension and the RSR coefficient, and the roughnesses of the class A and C standard roads surface and the measured road surface were reconstructed. The comparison between their power spectrums shows that the proposed fractal model for the RSR appeass sufficiently accurate.

Direct current (DC) nitrogen arc melting technique is presented, which allows for insitu preparing TiN layers on Ti-6Al-4V substrate. The microstructures，hardness and wear properties of the TiN layers were investigated by scanning electron microscopy, X-ray diffraction and microhardness testing instrument. The effects of arc current on microstructure and properties of TiN layers were discussed. The TiN layer is mainly composed of TiN dendrites and the content of the TiN dendrites gradually decreased. The TiN layer has a good metallurgical bonding with substrate. With an increase of arc current from 60 A to 100 A, the amount of TiN dendrites increased, and the layer hardness and wear resistance enhanced. At the condition of 100 A, the TiN layer highest hardness reached 1885 HV which is about 5 times that of substrate. At the same time, the wear resistance of TiN layer was significantly increased.

Co-based alloy coating was deposited on T10 tool steel by powder feeding laser cladding. Sections of such coatings were examined to reveal their microstructures and phases using scanning electron microscope (SEM) and X-ray diffractometer (XRD). The results showed that the prime phase  γ-Co and other phases, including Cr23C6, Co7W6 and CrNi existed in the coating. Some different solidification morphologies, such as planar (at the interface), cellular and dendrite formed, varying from the interface to the surface. Fine microstructures of dendrite in dendritical regions strengthened the coating which caused the increases in microhardness and corrosion resistance in the laser cladded coating.

The relaxing-retightening characteristics and the lifespan prediction of the high toughness spheroidal graphite cast iron under the conditions of variable high temperatures and plasticity were investigated experimentally. A model for its relaxingretightening lifespan prediction was built and the calculation analyses were performed to explore the working behavior and the lifespans after repeated relaxingretightening. The results show that an exponential relationship exists between the equivalent failure energy and the cycle number before failure, and the predicted lifespan is related to both the pretightening load and the initial extension.

Aiming at the shortages of the tip-shaped electrode tool that is used in current researches on electrorheological(ER) fluid-assisted polishing, for example,requiring the polishing gap between tool and workpiece surface in order of magnitude of μm and corresponding high equipment positioning accuracy,as well as need for the auxiliary electrode to polish the non-conductive workpiece, a new type of integrated electrode polishing tool was developed. The construction of the tool was described and its electric field was calculated. With this tool the polishing gap can reach to the order of magnitude of mm. The tool can polish conductive as well as non-conductive workpiece. The polishing experiments were made on the workpiece of WC and optical glass with the new tool. The relationships between the surface roughness and electric voltage, rotating speed, concentration of abrasive particles, polishing time, etc.,were given by individualfactor experiments. The experimental results show that, after 10 min polishing, the surface roughness of WC workpiece is dropped from Ra 66.48 nm to 33.18 nm, and for optical glass from Ra 11.02 nm to 3.67 nm.

The tribological characteristics of MoS2/PTFE composite versus quarty glass under water lubrication, low speed and higher load were in vestigaled on the type M-200 friction and wear tester. It was found that the friction factor between MoS2/PTFE composite and quarty glass is lower than 0.005 under water lubrication, demonstrating the ultra lubrication behavior with stable friction factor and low wear rate. The extreme low surface roughness and excellent water affinity of the quarty glass surface are the key factors to renlize the ultra lubrication. Addition of hard filler into the friction material tends to destroy the quarty glass surface, results in deterioration of tribological performance.

An approach based on model was employed to identify the rotor bending deformation degree. The original vibration signals of the rotor system were recorded, the difference between the online detected vibration signals and the original signals were computed. Combining with the rotor system dynamics model in normal state, the equivalent loads on each node were obtained, and the online bending degree of the rotor was identified by analyzing the equivalent loads. In view of a lot of noise existing in the signals, a denoise approach based on the empirical mode decomposition was proposed and employed. The results of the numerical examples show that the proposed approach is effective in identification of the rotor bending deformation degree.

To apply the theory of wavelet singularity in the vibration signal processing of the high-speed motor spindle, the reconstruction method of the wavelet singularity signal was analyzed, and an algorithm to detect the vibration signal singularity of the motor spindle was proposed. A testing and signal processing system was built for the motor spindle. According to the different characteristics of the signals and noises at every scale space after the wavelet transform, the signal reconstruction by the inverse wavelet transform extracted the vibration signal characteristics of the motor spindle. Simulation results show that the proposed signal processing method can remove the effect of the noise on the machining process monitoring system, predict the mechanical failure signal, and extend the lifespan of the motor spindle.

A systemic graph model and an analysis method were proposed for the planetary speed-shifting mechanism based on the graph theory. The graphs for the structural analysis, for the working condition, for the rotational speed analysis, and for the torque analysis were obtained by the topological transform of the systemic graph model, the corresponding mathematical models were built, and the automatic analyses of the structural features, the kinematics, the dynamics, and the efficiency of the planetary speed-shifting mechanism were realized.

The structure of the vehicle semi-active suspension with the control valve was presented according to its operation principle. The heat generation mechanism and the heat balance of the semi-active hydro-pneumatic spring were analyzed from the energy transform character of the working shock-absorber and its influence on the seal reliability.The equation of integrated heat transfer were derived with the object of oil and nitrogen respectively based on proper assumption and the knowledge of heat transfer and engineering thermodynamics. A thermodynamic model was built for the semi-active hydro-pneumatic spring based on the first law of thermodynamics. The structure parameters of the system were given and the influences of relevant factors on the temperature rise were analyzed by programing. The conclusions provide a reference for the design of the hydro-pneumatic spring.

A new design method based on the flat elliptic torus was proposed to design the flat hydrodynamic torque converter for the passenger car with more reasonable blade form and better performance. A new flatness ratio was defined as the ratio of minor axis to major axis of the ellipse, so its change can reflect the change of whole torus. Based on the analysis of the momenturn distribution on the performance of torque converter, the traditional blade design method on the basis of uniform momentum distribution was inproved, a quachratic function distribution of momentum was used to design the blade for the different vane wheels, and the flat torque converter blade with better form was achieved. The performances of the flat torque converters designed by both the new and the traditional torus design methods were predicted, resulting in that the former is better than latter under the same flatness ratio.

Concerning the dynamic character of grid system, a grid resource monitoring and prediction system is designed to provide online information for grid users and scheduler. This system is based on web service resource framework. The overall structure, the work flow and information flow of the system are expatiated in detail. The performance of the prototype system is evaluated. Analysis and evaluation indicate that the proposed system is applicable for online monitoring and prediction of grid resource information with low running overhead, friendly user interface, universal data format. Also the system can integrate seamlessly with grid environment as an independent subsystem.

In this work, the direction relation matrix is used to describe the relations between the Minimum Bounding Rectangles (MBR) of spatial regions. The composition of direction relations proposed by Skiadopoulos is formally described and refined. Then a composition method of direction relation matrix is proposed, which is easier to be realized. The proposed method simplifies the operation ‘Most’, making the process of composition more concise. By defining the minimum and maximal operators, the algorithm ‘Most’ is realized, which provides the basis of the algorithm of composition. By defining the operator of power, the algorithm ‘Compose’ is realized and verified. The realization of the algorithm ‘Compose’ makes the composition easier for application.

In order to realize effective tracking of output of nonlinear systems with constraint and model uncertainty in specified time domain, improved clonal selection algorithms are employed to solve optimization problems in iterative learning control. A clonal selection algorithm based nonlinear optimal iterative learning control is proposed. After each iteration, a clonal selection algorithm is employed to search optimal input for next iteration, and another clonal selection algorithm is used to update the plant model. Simulations show that the proposed method converges faster than GA-ILC, and is able to deal with constraint on input and model uncertainty. Satisfactory tracking performance can be obtained after a few iterations.

A novel fast local feature description method in real-time image matching is proposed, called Affine Invariant Fast Local Feature (AIFLF). A fast local character descriptor is proposed using affine moment invariants based on normalized gradient value of local neighbor area to the centre point. Simulation experiment show that, for comparative recognition rate, the run time of the proposed AIFLF is obvious less than that of classical SIFT arithmetic. Another matching experiment is conducted, in which the datasets are composed of standard evaluation images, which are taken by mobile robot platform. Performance evaluations show that AIFLF generally outperforms SIFT and SURF, especially in image scale, visual angle, and rotation transformation. Therefore, AIFLF is suitable for real-time image matching application.

Service discovery is the technology of finding needed services in network, which is a key aspect in pervasive computing environments. This paper proposes a novel service discovery protocol, which is named Piggybacking advertisement information based service discovery protocol(PAISDP). In PAISDP, by means of piggybacking it in the node's service reply packets, part of advertisement information of a reply node can be propagated along the reply path, which expands its transmission area. Theoretical analysis and Glomosim simulation results demonstrate that PAISDP can reduce the number of service request packets, save the response time, and improve the efficiency of service discovery.

Based on difference expansion and difference shifting a novel lossless data hiding algorithm is proposed. A sequence of pixels with grey levels is obtained by scanning the image in a given order. Then the difference of each adjacent pixel-pair is calculated. If the difference is larger than K-1 (K is a positive integer chosen by the user based on the embedding capacity), it is shifted right; if the difference is smaller than-K, it is shift left; if the difference falls between -K and K-1, it is used to embed the data. At the same time the distortion caused by expansion is uniformly distributed to the two pixels, which keeps the high quality of the image. Experimental results demonstrate that the proposed scheme can embed a larger payload while keeping the same Peak Signal-to-Noise Ratio (PSNR).

We propose a new image fusion algorithm based on finite ridgelet transform and cycle spinning. The finite ridgelet transform provides a flexible multiresolution, local and directional image expansion, and also a sparse representation for two-dimensional piecewise smooth signals resembling images. However, finite ridgelet transform lacks translation invariance that the fused image introduces many artifacts. We use the cycle spinning technique to develop translation invariant contourlet fusion rule. This method can effectively eliminate the Gibbs phenomena, extract the character of original images and preserve more important information. Subjective and objective standard evaluations of the experiment results show that this proposed method outperforms conventional methods in terms of better image character extraction and edge character description.

The dynamic vibration model of a mobile manipulator with suspension system is built with Finite element method (FEM). Using this dynamic model and the pseudo-excitation method (PEM), the transient Power spectral density (PSD) of the mobile manipulator in random vibration is obtained. This result can provide valuable reference for the suspension design of the mobile manipulator.

The function and effect of the connecting mechanics in robot reconfiguration and locomotion were analyzed. Then a novel hook-type mechanics was designed for modular robot. The mechanism can provide dependable conjunction for adjacent modules in robot motion, and quick connection/ disconnection for adjacent modules in reconfiguration. The connecting mechanics was composed of micro DC-motor, active hooktype rod mechanism and passive connecting board, which possesses the function of alignment and self-locking, no motor torque requirement after docking and energy-saving. The connecting principle, condition and mechanics characteristics of the mechanism were studied. Experiments were carried out and results show that the designed mechanism is efficient and it can perform connection even with certain geometrical error.

The characteristics and main factors of antenna pointing and tracking system for tracking performance are analyzed, and the mathematic model is establish for the system. According to the system characteristics, the design process of Cerebellar Model Articulation Controller (CMAC) network combined with PID control method is described. The advantages of the proposed method are analyzed. This method uses the fast self-learning and precise approaching of CMAC networks as the feed-forward control to get the object model; then together with the traditional PID control method it can have the advantages of fast response, high precision and robustness. Simulation results show that the proposed control method can effectively inhibit friction torque and provide stable output and robustness. The tracking precision of the proposed control method is one order of magnitude higher than that of PID control method alone.

In order to weaken the effect of dead-time in space vector pulse width modulation on the speed control system of permanent magnet synchronous motor, the nonlinear model of the inverter and the model of the whole system are established respectively. Combined with model reference control and sliding mode control, a double closed-loop second-order sliding mode control method based on voltage reference model is proposed. This method can reduce the chattering phenomenon in traditional sliding mode control, meanwhile realize automatic compensation for the nonlinear disturbances of the inverter. Simulation results show that the proposed method can ensure global stability, strong robustness, accurate and fast speed control performance; it can also reduce current harmonic and torque pulse evidently.

Many experiments have shown that laser diodes of poor quality often have the shortcoming of fluctuation in electric derivative curve and in optic derivative curve. The relationship between the fluctuation and the reliability of the laser diodes are discussed in this paper. Theoretical analysis and aging experiments show that if serious fluctuation occurs in electric derivative curve and in optic derivative curve, then the devices are unreliable. The electric derivative curve and optic derivative curve can be used as an indicator of the reliability of the laser diodes.

Based on the structure model of the hardware system of particle image velocimetry and general characteristic of optoelectronic transform of the charge coupled deveice(CCD), a theoretical equation to calculate the sum of the gray levels of the pixels of a real spherical particle image captured by CCD camera was derived from the Mie's scattering theory. To validate the derived equation, the relationships of the particle image gray level with the exposure time, laser light intensity and particle size were investigated employing 4 kinds of standard particle with different sizes. The results show that there is roughly linear relationships existing between particle image gray level and both exposure time and laser light intensity, and the image gray level ratio of 2 standard particles with different sizes is near the ratio of the size square of particles. All the experimental results are in good agreement with those from the derived theoretical equation.

Multi-input and Multi-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) system has attracted great attention as a solution of highquality service for next generation of wireless communications. However, one of the main shortcomings of OFDM is its high Peak to Average Power Ratio (PAPR), which seriously limits the performance of High Power Amplifier (HPA). A PAPR reduction scheme based on MultiSelect Mapping (MSLM) is proposed for MIMO-OFDM system. This method divides the transmit data into multi-groups for scrambling code with the same group data length at the transmit end of the MIMO-OFDM system, and then performs Select Mapping (SLM). The MSLM can reduce the PAPR of MIMO-OFDM signal, meanwhile decrease the computational complexity. Simulation results show that, regarding PAPR, the MSLM method outperforms the conventional SLM algorithm by 1.3 when the select branch number is 16 and the value of Complementary Cumulative Distribution Function (CCDF) is 10-3. Its symbol error rate performance is also good.

Based on fourth-order cumulant and the special mutual coupling transform model of uniform and linear arrays, a novel efficient mutual coupling compensation algorithm for estimation of Direction of Arrival (DOA) is proposed. This is an online calibration method and the calibration sources are not required. Although the fourth-order cumulant is more complex than traditional second-order method, it can obtain more spatial information and the number of mutual coupling coefficients is not expanded with the increase in virtual arrays. In the case of Gaussian color noise, simulation results demonstrate the effectiveness of the proposed technique. The results also show that the estimation resolution of the algorithm is higher than that of both the second-order mutual coupling calibration method and the traditional fourth-order method without mutual coupling consideration.

To optimize the soft handover algorithm for WCDMA network, a new position assisted soft handover algorithm is proposed based on the forecast of handover. This algorithm is developed on the basis of the Universal Telecommunications Radio Access (UTRA) soft handover algorithm. It forecasts the handover with different MS's position messages, and then adjusts the handover thresholds dynamically to improve the system performance. This algorithm is tested by simulation and results show significant improvement over the UTRA soft handover algorithm in terms of Mean active set number (MASN) and Active set update rate (ASUR), which can be remained stable. Therefore, the new algorithm can improve the system efficiency.

A noreference image quality assessment metric for JPEG2000 code images is presented. First, the edge points in the structuretexture region of the reconstructed picture are detected based on the principle of Human Visual System (HVS). Then according to the gradient direction of the edge point, the edge feature is extracted, which is comprised of the pixels in the neighborhood of the edge point and is perpendicular to the gradient direction. Finally, a noreference quality assessment model based on OLSRBF network is trained to predict the quality of JPEG2000 coded images by using the image feature and the image subjective quality rating. Experimental results show that, compared with the metrics proposed by Ong and by Marziliano, the performance of the proposed metric is more consistent with subjective evaluation.

Lowcomplexity and highperformance of diversity combing schemes always conflict. A new hybrid combining technique named SSCSC is proposed, which is composed of Selection Combining (SC) and SwitchandStay Combining (SSC). The SSCSC scheme with 2L branches in Rayleigh fading channel is studied. The closedform expressions for the average output SignaltoNoise Ratio (SNR), Bit Error Ratio (BER), Level Crossing Rate (LCR) and Average Output Duration (AOD) of the SSCSC system are provided. Finally, the proposed SSCSC is compared with SC and with Generalized Selection Combining (GSC). Results show that the performance of SSCSC is not as good as that of SC and GSC but is still acceptable. From the standpoint of implementation, SSCSC is characterized by simple structure, easy realization and resources saving. With these characteristics, SSCSC is feasible for practical application.

To improve the spectral efficiency of current AmplifyandForward protocol based on the Distributed SpaceTime Code (AFDSTC), we proposed an improved Selection AmplifyandForward protocol based on the Distributed SpaceTime Code (SAFDSTC). This improved protocol shortens the cooperative period from four time slots to three slots, that saves 33.3% of the symbol transmission bandwidth. Theoretical analysis and simulation results show that, at the same spectral efficiency, the proposed SAFDSTC protocol significantly outperforms the AFDSTC protocol in terms of the consumed power, outage probability and bit error rate.

Under the constraints of interference temperature and total transmit power, an optimal subcarrier and power allocation algorithm is proposed for the uplink of cognitive radio networks to maximize the system throughput. The cognitive radio networks are based on the Orthogonal Frequency Division Multiple Access (OFDMA). The problem is formulated as a nonconvex optimization. Applying the Lagrange dual decomposition method and KarushKuhnTucker (KKT) condition, the proposed algorithm converges to the optimal solution. Simulation results show that this algorithm can achieve the performance of exhausted scheme while significantly decreasing the computational complexity.

A design method for the Ultra Wideband (UWB) pulse with the optimal combination of differential Gaussian pulses is investigated. A series of the optimal simple order differential Gaussian pulses are constructed using energy shift action of the differential factor and the spectral spreading effect of the pulse shaping factor. According to indoor and outdoor radiation mask standard, an optimal solution of the weight factor is derived by the restrained minimum mean square error algorithm; and a universal UWB combined pulse compatible with the indoor and outdoor transmission environments at whole frequency band is designed. The simulation results indicate that the designed combined pulse is characterized by good capability of approach to the Federal Communication Commission radiation mask standard and least bit error rate under multiuser interference environment. The proposed design method is important to the rational design of UWB pulse with a given frequency spectrum.

Magnetorquers and reaction wheels are important control actuators for modern small satellite. The mathematical model for attitude control using magnetorquer and reaction wheel is developed. The necessity to combine magnetorquers and reaction wheels for satellite attitude control in the control algorithm design is analyzed. Using control allocator, a combined control scheme is proposed based on the reaction wheels and magnetorquers to be used. Two control allocation techniques are developed to automatically redistribute the required control torque among reaction wheels and magnetorquers. Numerical simulation demonstrates that the proposed control technique can reduce the opportunity of saturation and the system power consumption without reducing the attitude control accuracy. It can also prolong the life of space task. Other advantages include simple algorithm design, less computation cost and realtime calculation on board.

The atmosphere drag dissipation is the major factor that affects the lifespan of low orbit spacecraft. Using a backup satellite, which runs on a high orbit, may increase the lifespan of the entire formation system. The orbit transfer strategy for the backup satellite maneuvering to the vicinity of the chief is one of the vital issues for satellite formation reconfiguration. In the work, a Hohmann transformation and active phase modulation orbit transformation scheme is designed to transfer the inplane backup satellite to the target orbit, hence to accomplish the formation reconfiguration mission. Simulation results demonstrate the effectiveness of the proposed method, and also illustrate that the Hohmann method is fuel optimal but consumes much more time. While, the active phase modulation method though reduces the orbit maneuvering time, it consumes more fuel. This conclusion will be helpful to the future long lifespan formation design and formation reconfiguration issue.

The large angle attitude maneuver control of spacecraft with bounded inputs is investigated. To remove the singularity due to the use of Euler angle in large angle attitude maneuver, the kinematics of the spacecraft is described by quaternion. Using Lyapunov theory, and motivated by the recent results on invariant set stability theorems of nonlinear impulsive hybrid systems, a class of large angle attitude maneuver hybrid dynamical controller with bounded inputs is derived. Theoretical analysis and simulation results indicate that the proposed control algorithm has excellent dynamic performance and can be easily designed and realized.

RNA from waste Brewer′s yeast was studied as raw material to analysis the effect of HPEF on the dissolution condition of RNA by water, ethanol, and TCA as extraction solvent, respectively. The mathematical model of RNA rapid extraction from waste Brewer′s yeast by HPEF was made use of twice general purpose rotation battery testing design. The mathematical model was given. The RNA yield by ethanol as extraction solvent was 1.69 times of it by water. The RNA yield enhanced 40.86%. The best parameters of extraction RNA from waste Brewer′s yeast by HPEF were ethanol as extraction solvent, 50 kV/cm as electric field strength, 2 as pulse number(0.0067s as pulse time) ,liquidsolid ratio as 30∶1, in which condition that the RNA yield reached to 0.85%.