Diffusion tensor interpolation profile control using non-uniform motion on a Riemannian geodesic

Tensor interpolation is a key step in the processing algorithms of diffusion tensor imaging (DTI),such as registration and tractography.The diffusion tensor (DT) in biological tissues is assumed to be ...     

Multi-channel fast super-resolution image reconstruction based on matrix observation model

A multi-channel fast super-resolution image reconstruction algorithm based on matrix observation model is proposed in the paper,which consists of three steps to avoid the computational complexity: a single image SR reconstruction step,a registration step and a wavelet-based image fusion. This algorithm decomposes two large matrixes to the tensor product of two little matrixes and uses the natural isomorphism between matrix space and vector space to transform cost function based on matrix-vector products model to matrix form. Furthermore,we prove that the regularization part can be transformed to the matrix formed. The conjugate-gradient method is used to solve this new model. Finally,the wavelet fusion is used to integrate all the registered highresolution images obtained from the single image SR reconstruction step. The proposed algorithm reduces the storage requirement and the calculating complexity,and can be applied to large-dimension low-resolution images.     

The frequency characteristic of chaotic synchronization systems and weak signal detection

A concept of frequency character of a chaotic synchronized system (CHSS) is proposed. The nature of the system can be described in the frequency domain with the concept. A simple model to measure the frequency character is designed, and the characteristic curve of Chua's CHSS is obtained. Some results from theoretical analysis and numerical simulation indicate that the system possesses multiband of frequencies with distinct features shown in each band. Thus it may offer various resources of frequencies, fn particular, it is capable of detecting weak signals drowned in noise in some bands. Both the concept of frequency character and the characteristic curve of CHSS provide a scientific basis for us to gain a deeper insight into the inherent function of information processing in CHSS, and to utilize properly the information resources of CHSS as well.     

Stiffness estimation of a parallel kinematic machine

This paper presents a simple yet comprehensive approach to quickly estimating the stiffness of a tripod-based parallel kinematic machine. This approach can be implemented in two steps. In the first step, the machine structure is decomposed into two substructures associated with the machine frame and parallel mechanism. The stiffness models of these two substructures are formulated by means of virtual work principle. This is followed by the second step that enables the stiffness model of the machine structure as a whole to be achieved by linear superposition. The 3D representations of the machine stiffness within the usable workspace are depicted and the contributions of different component rigidities to the machine stiffness are discussed. The result is compared with that obtained through finite element analysis.     

Optimal operation of cascaded hydroelectric power plants in the power market

An improved network flow algorithm, which includes the minimum cost network flow and the same period network flow, is proposed to solve the optimization of cascaded hydroelectric power plants in a competitive electricity market. The typical network flow is used to find the feasible flow and add the discharge water to different cascaded hydroelectric power plants at the same step. The same period network flow is used to find the optimal flow and add the power output at a different step. This new algorithm retains the advantages of the typical network flow, such as simplicity and ease of realization. The result of the case analysis indicates that the new algorithm can achieve high calculation precision and can be used to calculate the optimal operation of eascaded hydroelectric power plants.     

Parameter Identification and Application of Slippage Kinematics for Tracked Mobile Robots

A new parameter identification method is proposed to solve the slippage problem when tracked mobile robots execute turning motions. Such motion is divided into two states in this paper:pivot turning and coupled turning between angular velocity and linear velocity. In the processing of pivot turning, the slippage parameters could be obtained by measuring the end point in a square path. In the process of coupled turning, the slippage parameters could be calculated by measuring the perimeter of a circular path and the linear distance between the start and end points. The identification results showed that slippage parameters were affected by velocity. Therefore, a fuzzy rule base was established with the basis on the identification data, and a fuzzy controller was applied to motion control and dead reckoning. This method effectively compensated for errors resulting in unequal tension between the left and right tracks, structural dimensions and slippage. The results demonstrated that the accuracy of robot positioning and control could be substantially improved on a rigid floor.     

Optimization of satellite searching strategy of the non-stationary antenna

The tiny searching step length and the satellite distribution density are the major factors to influence the efficiency of the satellite finder, so a scientific and reasonable method to calculate the tiny searching step length is proposed to optimize the satellite searching strategy. The pattern clustering and BP neural network are applied to optimize the tiny searching step length. The calculated tiny searching step length is approximately equal to the theoretic value for each satellite. In application, the satellite searching results will be dynamically added to the training samples to re-train the network to improve the generalizability and the precision. Experiments validate that the optimization of the tiny searching step length can avoid the error of locating target satellite and improve the searching efficiency.     

Internal crack recovery of 20MnMo steel

According to the results of physical modelling, SEM and SAM analysis of 20MnMo steel samples, internal cracks of metal parts are recoverable. The motive power of the recovery is atom diffusion and migration from matrix to voids. The recovery process consists of two steps. In the first step, the void area is filled up with a kind of metal mass, beginning from the crack tip. There are many microvoids in the mass with different microstructure from the matrix. In the second step, microvoids decrease in size and number, and the mass microstructure approaches the matrix, with the heating temperature increasing and the holding time prolonging. Recovery tests on rejected heavy forgings are successfully processed. It is believed that the recovery technique is a potential method for improving the internal quality and reducing the production loss and cost of metal products. Similar method can be used to treat other metal construction parts for rescuing them or prolonging their service life. Further research and de     

Observer-based Guidance Law Accounting for Second-order Dynamics of Missile Autopilots

Accounting for the missile autopilot as second-order dynamics, an observer-based guidance law is designed based on the dynamic surface control method. Some first-order low-pass filters are introduced into the design process to avoid the occurrence of high-order derivatives of the line of sight angle in the expression of guidance law such that it can be implemented in practical applications. The proposed guidance law is effective in compensating the bad influence of the autopilot lag on guidance accuracy. In the simulations of intercepting non maneuvering targets, targets with step acceleration, and targets with sinusoidal acceleration respectively, the guidance law is compared with the adaptive sliding mode guidance law in the presence of missile autopilot lag. The simulation results show that the proposed guidance law is able to guide a missile to accurately intercept a maneuvering target, even if it escapes in a great and fast maneuver and the autopilot has a relatively large lag.     

Robot stereo vision calibration method with genetic algorithm and particle swarm optimization

Accurate stereo vision calibration is a preliminary step towards highprecision visual positioning of robot. Combining with the characteristics of genetic algorithm (GA) and particle swarm optimization (PSO), a threestage calibration method based on hybrid intelligent optimization is proposed for nonlinear camera models in this paper. The motivation is to improve the accuracy of the calibration process. In this approach, the stereo vision calibration is considered as an optimization problem that can be solved by the GA and PSO. The initial linear values can be obtained in the first stage. Then in the second stage, two cameras’ parameters are optimized separately. Finally, the integrated optimized calibration of two models is obtained in the third stage. Direct linear transformation (DLT), GA and PSO are individually used in three stages. It is shown that the results of every stage can correctly find nearoptimal solution and it can be used to initialize the next stage. Simulation analysis and actual experimental results indicate that this calibration method works more accurate and robust in noisy environment compared with traditional calibration methods. The proposed method can fulfill the requirements of robot sophisticated visual operation.     

Multidisciplinary design optimization of adaptive wing leading edge

Adaptive wing can significantly enhance aircraft aerodynamic performance, which refers to aerodynamic and structural opti-mization designs. This paper introduces a two-step approach to solve the interrelated problems of the adaptive leading edge. In the first step, the procedure of airfoil optimization is carried out with an initial configuration of NACA 0006. On the basis of the combination of design of experiment (DOE), response surface method (RSM) and genetic algorithm (GA), an adaptive air-foil can be obtained whose lift-to-drag ratio is larger than the baseline airfoil’s at the given angle of attack and subsonic speed.The next step is to design a compliant structure to achieve the target airfoil shape, which is the optimization result of the previous step. In order to minimize the deviation of the deformed shape from the target shape, the load path representation topology method is presented. This method is developed by way of GA, with size and shape optimization incorporated in it simul-taneously. Finally, a comparison study with the Solid Isotropic Material with Penalization (SIMP) method in Altair OptiStruct is conducted, and the results demonstrate the validity and effectiveness of the proposed approach.     

LS-based discrete-time adaptive nonlinear control——Feasibility and limitations

Global stability and instability of a class of discrete-time adaptive nonlinear control systems are investigated.The systems to be controlled are assumed to be linear in unknown parameters but nonlinear in dynamics which are characterizEd by a nonlinear function f(x).It is shown that in the scalar parameter case,when the standard least-squares (LS) method is used in estimation,the certainty equivalence adaptive control is globally stable whenever f(x) has a growth rate |f(x)| =0(||x||b) with b<8.Moreover,in the case where b≥8,it is also shown that the dosed-loop adaptive control system does not have global stability in general.Both the results found and the new analytical methods introduced may be regarded as a basic step for further study of discrete-time adaptive nonlinear control systems.     

Research on a New-style Visual Sensor for Measurement

First,the constitution of traditional visual sensor is presented.The linear camera model is introduced and the transform matrix between the image coordinate system and the world coordinate system is established.The basic principle of camera calibration is expatiated based on the linear camera model. On the basis of a detailed analysis of camera model,a new-style visual sensor for measurement is advanced.It can realize the real time control of the zoom of camera lens by step motor according to the size of objects.Moreover,re-calibration could be avoided and the transform matrix can be acquired by calculating,which can greatly simplify camera calibration process and save the time. Clearer images are gained,so the measurement system precision could be greatly improved.The basic structure of the visual sensor zoom is introduced,including the constitute mode and the movement rule of the fixed former part,zoom part,compensatory part and the fixed latter port.The realization method of zoom controlled by step motor is introduced. Finally,the constitution of the new-style visual sensor is introduced,including hardware and software.The hardware system is composed by manual zoom,CCD camera,image card,gearing,step motor,step motor driver and computer.The realization of software is introduced,including the composed module of software and the workflow of measurement system in the form of structured block diagram.     

Evaluation of properties for lubricant filter in diesel engines

The properties of lubricant filters in diesel engines directly affect operation of the lubricant system,and lubricant filters are apt to be impacted by many factors. Therefore, scientific and sensible methods evaluating the properties for lubricant filter diesel engines are necessary to monitor filter properties on line and dynamically. This paper applies ferrographic techniques and adopts sampling methods that oil specimens are synchronously obtained in front of and behind filter elements to monitor the filters of ISUZU DA -220 diesel engine in two FD50 forklifts. Results show that the combination of ferrographic techniques and above sampling methods is effective in analyzing the whole operating process of filters used in diesel engines. The service life and ruined type of filter can be estimated through the relationship between ferrographic readings in front and behind of filter and operation time. Furthermore, through a great deal of tests, a series of experimental curves of readings and time and characteristic parameters for filters used in different machines can be gained, which has guiding significance to the selection and maintenance of the filters. But because of the limitation of the ferrographic technique, the debris on the substrate prevents determination of sizes. It is difficult to judge accurately the size of debris that a filter can filter.     

Analysis of micro vortex metallization and introduction of evaluation factor in mixing process

To improve the mixing efficiency in water purification or wastewater treatment process and understand the mechanism of mass transfer,and a suitable evaluation factor is introduced to evaluate the efficiency of mixing process.The diffusion mass transfer under turbulent condition is investigated based on dynamic and mathematical analysis.The results indicate that submicroscopic diffusion is the rate-limiting step in mass transfer,and the inertia effect of micro vortex causes the phase mixing.An excellent efficiency can be obtained by controlling the scale of micro vortex within millimeter.Furthermore,a new indicator named mixing factor(IH)is proposed to evaluate the efficiency of mixing processes,which is more feasible than conventional evaluation methods,because of its connection of mixing extent with energy consumption.     

Iterative Detection and Decoding Algorithm in Dual Polarized Land Mobile Satellite MIMO Systems

An iterative detection and decoding algorithm with outer code decision feedback is proposed for the dual polarized （DP） land mobile satellite （LMS） MIMO systems using concatenated codes. A feedback structure is added after the outer decoder in the proposed algorithm. The feedback information is exploited to control the detecting list in the MIMO detector and reduce the number of symbols which have to be processed at each iteration. As a result, the computational complexity is reduced. Meanwhile, the successfully decoded outer code words are used to calculate the more reliable initial information for the inner decoder and the system performance can be improved by this step. The simulation results show that the proposed algorithm can reduce the computational complexity compared to the traditional iterative detection and decoding algorithm and achieve better performance.     

Sloping-and-shaking——Multiway merging and sorting

Most traditional merging and merging-based sorting algorithms are based on 2 sorters or 2 comparators A new merging technique is developed, namely sloping-and-shaking multiway merging, and a corresponding mul-tiway sorting method based only on k-sorters is proposed The sloping-and-shaking merging algorithm merges k sorted lists into one, where k can be any prime number The merging process is not a series of recursive applications of 2-way morging It sorts the keys on the m × k plane in vertical and horizontal directions, then along sloping lines with various slope rates step by step Only k-sorters are needed in the merging or sorting process. The time needed to merge ksorted lists, with m of each, is ( k + [log2( m / k) ]) tk, and the time for sorting N keys is (1 + (p - 1) k + 1/2( p -1) (p - 2)[ log2k])tk, where p - logkN, and tk is the time to sort k keys. The proposed algorithms can be implemented either by hardwared sorting networks, or on general purpose parallel and vector machines The tradition     

A DEVELOPING TOOL FOR THE EXPERT SYSTEM IN TECHNOLOGY DESIGN AND EXPERT SYSTEM FOR COCOON COOKING

This paper demonstrates the general character of some technology designing processes through their analysisand introduces a developing tool for the expert system in technology design.With this tool a particular domain ex-pert can directly establish a knowledge base so as to form a practical expert system,and thus enhanca correctness ofknowledge experssion and the developing efficiency of the expert system.It also discusses in detail the mech-anism of reasoning,interpreting and knowledge obtaining.The knowledge base consists of three parts:classifyingrules,essential data,and regulating rules.It can be formed by means of the expert dialouge and edition.In its ap-plication,the knowledge base can constantly accumulate successful experience to achieve itsself-study function.The paper shows the way to describe the knowledge in a particular domain and the process of applying this tool ina particular domain. The tool is written in Turb-Prolog language,And an expert system for cocoon cooking isprovided.     

Research on Selective Shredding of Wasted Printed Circuit Boards

Electronic scrap, especially wasted printed circuit boards (PCBs), is regarded as an environmental challenge. At present, the physical separation is thought to be the environmental friendly and economical method of treating and reutilizing electronic waste. An effective liberation of metals from non-metallic components is a crucial step towards mechanical separation and recycling of wasted PCBs. In this paper, the selective shredding theory and mechanics characteristics of wasted PCBs were analyzed, and the shredded experiments of wasted PCBs by hammer mill were investigated. The result shows that the selective shredding exists in the wasted PCBs shredded process by hammer mill. The shredding velocity of non-metallic components is far greater than that of metals in the wasted PCBs shredding, which makes the metals concentrate in the coarserfr action. And the impact force of hammer mill is superior to metai liberation from non-metallic components, a satisfied metal liberation degree can be achieved in the wasted PCBs shredding by hammer mill.     

Theoretical development for DSMC local time stepping technique

The direct simulation Monte Carlo(DSMC) method is the most mature and wildly used approach for nonequilibrium gas flow simulation.The phenomenological nature of this method brings flexibility to the computation algorithms.In this study,the theoretical foundations to decouple the molecular motion and collision within a time step are discussed in detail,which can be treated as criterions for the DSMC algorithms.Based on the theoretical developments,an improved local time stepping scheme is proposed,which specifies the movement time attribute and the collision time attribute for each representative particle.A free flow about a sphere body is considered as an example,which is compared with the calculations using the published local time stepping technique.The results show that the improved local time scheme is valid and is promising in realizing flow structures with strong variations.