Abstract:It is a challenge to integrate Multidisciplinary Design(MD), Multidisciplinary Analysis (MA), Multidisciplinary Optimization (MO) processes with the satellite system design flow. A system-oriented software framework was formulated and implemented for the satellite integrated design by using Variable Complexity Modeling (VCM) method and Production Data Management (PDM) technology. The design conception, structural components and functional characteristics were introduced. Then the software was tested by the example of Lunar Exploration Satellite conceptual design. The results show that it is an effective approach to apply Multidisciplinary Design Optimization (MDO) technology to satellite integrated design.

Abstract:Throttling Venturi for cryogenic propellants is the key component of the mass flow control system. The step motor was used to control the displacement of the tapered rod. And water is used in cold test. Through changing operating conditions, throat area and back pressure, the change rule of discharge coefficient and pressure recovery factor were found. Then liquid oxygen was used to modify the results of cold test. The mass flow control system was used in firing test of tripropellant model engine, which shows the system can control the mass flow of liquid oxygen accurately and change the operating conditions successfully.

Abstract:Spray characteristics of gas-liquid coaxial shear and swirl injectors were studied by conducting experiments. The results suggest that the injector outlet expanding can improve atomization performance; for the two kind of injectors, that is, gas-liquid coaxial swirl injectors and gas-liquid coaxial swirl injectors, with a proper indent length，they have good atomization performance and proper flow performance; and under the same conditions, gas-liquid coaxial swirl injectors have better atomization performance than gas-liquid coaxial swirl injectors.

Abstract:On the basis of the analysis of the characteristic of the Photo-reconnaissance Satellite, a model was built which describes the interactions among the probability of target detection versus the satellite's inclination, the detection width, the max access gap and the target characteristics. The model formulates the relationships between the technical index and the tactical index, and can be used in the requirement analysis, system design and effectiveness evaluation of Photo-reconnaissance Satellite. The simulation results which takes the large-scale ships as detection target are given to illustrate the applicability of this model.

Abstract:Evolutionary algorithms are the main and effective methods in solving multi-objective optimization problems (MOP). Based on the NSGA-Ⅱ algorithm studied and analyzed, we improved its crowding mechanism by introducing the Niche theory to expedite its convergence velocity and improve its convergence precision. The representative test functions show that the improvements have higher computational efficiency and can obtain a reasonable distributing solution; it can also maintain the solutions' diversity.

Abstract:Based on the Kepler's equation, a new set of relative motion equations with elliptical reference orbits were derived. The equations are expressed by orbit elements, and can be used directly for formation flying orbit design. Several typical relative motions and the precision of the equations were analyzed. Furthermore, a linear formation and a perpendicular circles formation were suggested. The effectiveness was verified by the simulation results.

Abstract:A general method for calculating spacecraft collision probability is developed. In this method the input required to perform a calculation includes the respective state vectors, position error covariance matrices and physical sizes of objects involved. The method is valid for the general case because it only relies on the general form of error covariance matrices. The relative velocity is assumed to be vector having constant direction, and then the collision probability problem can be reduced to two dimensions in encounter plane normal to the relative velocity vector by eliminating the dimension parallel to the relative velocity vector. Three kinds of method resolving the two dimensions problem are developed and compared. Test case results indicate the method is valid and applicable.

Abstract:A contact algorithm which describes the contact interaction between SPH particles by means of Riemann solution was used to calculate the discontinuity of the variables defining the one-dimension fluxes. A weak wave approximation of the Riemann solver was adopted to deal with the weak discontinuity, while the non-iterative Riemann solution was introduced in strong discontinuity. Furthermore Taylor series was used to improve the calculation accuracy on the free boundary. In this case, there was no need to use artificial viscosity for the numerical viscosity of the new SPH algorithm. Compared with the original algorithm, the simulation results show that the modified contact algorithm has a good description of strong discontinuity, and improvement in dealing with the free surface.

Abstract:Experiments on transcriptome analysis have resulted huge genes expression data related with specific temporal and spatial information. These data can be used in new genes identification，analysis of genes express patterns and the annotation of genomes, which may provide the reference standard for experiment design and result analysis of transcriptome experiments. Since the alternative splicing of eukaryotic genes have found to be universal and play an important role in physiology and pathology, systematic analysis of alternative splicing is becoming a new hotspot of functional genome research. Facing the immense and exponential increase of experimental express data and more new genomes getting sequenced, there is exigent of the strategy which can handle transcriptome sequences in large scale and automatic way. We elucidate the algorithms, the computing requirements and programs in different transcriptome sequences analysis systems and propose a strategy more suitable for large scale analysis of alternative splicing.

Abstract:Modern semiconductor technology allows us to place hundreds of functional units on a single chip which provides limited global on-chip and off-chip bandwidths. General purpose processor architectures have not adapted to this change in the capabilities and constraints of the underlying technology, still relying on global on-chip structures for operating a small number of functional units. Stream processors, on the other hand, have a large number of functional units, and utilize multiple register hierarchies with high local bandwidth to match the bandwidth demands of the functional units with the limited available off-chip bandwidth. This paper describes the microarchitecture of MASA and presents the implementation of the application in fluid dynamics. We developed cycle-accurate simulator to evaluate the performance. The results show that the application on 500MHz MASA outperforms a 1.6G Itanium2 by a factor of 4. This research confirms that stream architecture has the potential to deliver high performance.

Abstract:Mobile ad-hoc networks are characterized by self-organization, rapid deployment and fault tolerance. A multi-robot formation supported by mobile ad-hoc networks is suitable to some special situations where the communication devices of mobile networks cannot be preinstalled. However, ad-hoc networks are of limited communication range and frequent topology change. If the communication distance of robot isn't taken into account, some robots will escape from the formation whenever it is not within the communication range of the networks. In order to ensure the integrality of the multi-robot formation, a potential field based approach was proposed, in which the special attractive force caused by inter-robot distance, together with the attractive force and the repulsive forces respectively caused by goal and obstacles, has been taken into account. The results in simulation demonstrate that the approach can effectively control the change of multi-robot formation in mobile ad-hoc networks.

Abstract:FDTD was used to make simulated analysis of the time domain antenna array. Patterns in H plane were measured through outdoor oscillograph. The results indicate that the array can be used in the practical UWB radar antenna arrays, which can increase the gain, the directionality and have wide beam width.

Abstract:TEM Horn is an ultra-wide-band antenna, which is usually employed in the analysis of frequency domain up to the present. A new concept is presented with wave mode theory. According to this concept, the impedance of antenna aperture cannot be regarded as the wave impedance in vacuum, but is connected with antenna size and flare angle. Because of the time sequence, the reflection is only connected with local structure. A TEM horn antenna is designed and fabricated. The experiment results show that its wave fidelity and impedance performance are excellent, so it is very valuable for the study of time-domain antenna.

Abstract:Conventional methods to detect changes between temporal images are subject to the effect of illumination variance and registration noise. The edge structure information in image was employed in this paper to detect changes. A new conception based on biological vision principle, called Edge Tag, was introduced to describe the edge structure. After the correlation calculation between two Edge Tags, decision rule was made to locate the outline of changed area. The Edge Tag based change detection was robust to illumination variance and registration noise. Experiments on simulated data and real images verified its superiority.

Abstract:In order to give a full play of SMP clusters, this research studied the method to improve the performance of Fox algorithm for parallel matrix multiplication exploiting optimization on single processor, OpenMP and MPI, which involves the levels of instruction, shared memory and distributed memory respectively. Through invoking mathematic library and hybrid programming, the numerical results derived on DeepComp 6800 are satisfactory.

Abstract:A simple and general expression for the relationship between the spatial correlation matrices of the MIMO wireless channel with and without the impact of mutual coupling is derived under reasonable assumptions in this paper. Some computational results and conclusions based on the expression are also given.

Abstract:By combining with the properties of coding and statistic of the plaintext, we discussed the differential properties of the ciphertext sequences which are generated by a nonlinear combined generator. A difference attack algorithm which attacks the nonlinear combined sequences was proposed. In the end of the paper, an attack example of the difference attack algorithm was supplied.

Abstract:In OLAP application, aggregation is the usual technique to improve the response speed of the users' query. However, there have been few attempts to completely characterize the ability to summarize measures along some dimensions. Based on this situation, this paper firstly gives some basic definitions about the dimension summarizability, and represents its taxonomy. Then it describes the technique of judging the summarizability in detail, and finally, its countermeasures are introduced.

Abstract:Although a large number of researches have been undertaken in the area of transcription start site (TSS) localization, the problem of TSS localization has not yet been fully resolved. According to the previous promoter prediction algorithm, a new sliding window based computational localization method for E. coli TSSs is proposed. The TSS-likelihood scores of each possible position in genomic sequences are calculated by the window classifier which is improved by introducing the composite motif model in the training procedure of original promoter classifier. The distribution of distances between TSSs and translation start sites (TLSs) is also utilized to calculate the TSS-position scores. Localization results are achieved from the final score profiles which combine TSS-likelihood scores and TSS-position scores. The test results on E. coli dataset show that the method can find the putative TSSs and decrease the number of false positives efficiently.

Abstract:The application of adaptive anti-jamming filtering in DS-MSK digitalized receiver is discussed in this paper. A novel structure named partly despread nonlinear filtering (PDNF) is proposed. It is developed from classic nonlinear filtering (NF). Fast refreshed subband adaptive filtering (FRSAF) algorithm is applied to PDNF structure to speed up convergence rate. This novel adaptive anti-jamming filtering scheme composed of PDNF structure and FRSAF algorithm outperforms the classic scheme composed of NF structure and LMS algorithm on convergence rate, robustness and output SINR. Simulation results demonstrated the efficacy of the novel scheme.

Abstract:There exit lots of complex interdependence and communications among decision-making entities because of combat resource entities clustering on task and commander controlling those resource entities to complete combat tasks. Excellent structure of military force should be required to accomplish missions. Military force is composed of two parts: one is collaboration among decision-making nodes of command and control; the other is hierarchy relationship of command among commanders. Military force designing is to optimizing collaboration and hierarchy among commander nodes. In this paper, we set relationship of commander from coordination net among commanders. The optimizing objective is to minimize the overall additional coordination imposed by hierarchy structure among commanders. Algorithms of optimized coordinate tree are employed to generate command relationship in military force.

Abstract:Track association has been recognized as one of the major problems in distributed multiple-radar multiple-target tracking systems. Tracks formed on the same targets by multiple radars may differ due to misalignment or bias error. So the traditional features, such as target position and speed, cannot be reliably used for track-to-track association. The information of relative positions among targets, however, is found to contain special characters and can be extracted as target topology vector of reference dynamically. Applying fuzzy pattern recognition to analyze the similarity of vectors or patterns can set up the criterion of association and provide prior information for alignment. Simulation results show that the proposed algorithm is effective to solve the association problem under the condition of inter-radar bias and robust to the random errors.

Abstract:A new micro-mechanic-hydrodynamic model(MMH-Model) to predict the yield stress of magnetorheological fluids has been developed . The storage modulus of a MR fluid with a three-dimensional chain structure model and the apparent viscosity of a MR fluid using the balance between the magnetic torque and hydrodynamic torque are determined. The magnetic interaction between the particles and the wall, as well as the static coefficient of friction, are considered. The predictions of the model are compared to preliminary experimental data obtained in a controlled stress plate-plate rheometer and other theoretical predictions. It is found that the model gives almost the correct yield stress for the MRFs in the magnetic fields lower than the saturation field, but underestimates the experimental results obtained in the magnetic fields higher than the saturation field.

Abstract:An active suspension control scheme using a combination of optimal control and backstepping technique is presented. It is based on a nonlinear half-car model fully considering the dynamics of the hydraulic actuator. The detailed procedure consists of two steps: firstly the linear quadratic optimal controller is designed based on the performance characteristics requirement in outer loop, and then the nonlinear terms caused by the hydraulic actuators are dealt with backstepping method in inner loop. Simulation results show that the car has safe maneuverability and excellent ride comfortability by using the proposed scheme.

Abstract:The finite-time stabilization problem of single chained system is investigated in this paper. The potential linear structure of the n-dimensional chained system is exploited, and then the chained system is divided into a scalar subsystem and a (n-1)-dimensional LTV subsystem. Furthermore, the controllability of the LTV subsystem which has a time-varying function system matrix is proved. Then, a discontinuous feedback control laws is proposed by using the terminal sliding mode control method along with a piecewise control strategy. The chained system is finite-time stabilized due to the finite-time convergence property of the terminal sliding mode. Finally, the proposed strategy is applied to a car-like wheeled mobile robot, and the results are verified by simulations.

Abstract:In view of Type I and Type II censored for exponential life distribution cases, the Mazzuchi-Soyer reliability growth model was extended to cover the life test. The Dirichlet distribution was taken as prior distribution in the model. The historical information and expert information were synthetically used. Combined with the life test data of each development stage, the joint posterior distribution of each stage reliability was presented. Then, the Gibbs sampling algorithm was used to compute the posterior inference. The Bayesian estimators and Bayesian lower bound were gained for each stage reliability. Finally, the example shows that the Bayesian model has apparent advantages.

Abstract:Considering that the atmospheric kinetic interceptor with invariable rolling rate has quick response and strong coupling, this paper firstly analyzes the advantage and disadvantage of the classic design method of the control system, and then it proposes the gain scheduling method based on the regional pole placement, which finds a Lyapunov function in the whole parameter space to guarantee system stability. Compared with the classic method, the new method is not only stable theoretically, but also convenient in calculation. Simulation results show that controller based on the method which be proposed in this paper has good performance.