Abstract:A new type of index structure called join predicate index (JPI) is described. The JPI can be used to improve the performance of joins in object relational data base systems. After the introduction of JPI, a join algorithm based on JPI is presented and the performance analysis formula is given. It is also proposed which should be the outer relation so as to decrease the expense of the join op-eration. Lastly, the basic JPI is extended to the join of n relations.

Abstract:In view of the system structure and transaction model of OODB,a practical and efficient recovery strategy—WAL＿P is proposed, which is implemented in the object-oriented database system KDOODB, and provide powerful support for the efficient implementation of the transaction management.

Abstract:As the design of products is becoming more complex, and the time it takes for these products to go on the market becomes shorter, the concurrent design technique is widely used. This paper proposes a distributed framework-YC-bridge, which supports the concurrent design of multi-domain complex products. Based on Client/Server middleware, the framework realizes design datamanagement based on design body model, tool encapsulation based on sementic model, design process management based on the extended net graph model. YC-bridge has been applied successfully in practical design work.

Abstract:After the description of some collision detection methods, we present a new method for collision detection for geometric models described by TIN. This method solves the problem of completeness control effectively. It has been used successfully in our route planning system.

Abstract:Memory locking is a way to ensure that a process stays in main memory and is exempt from paging. In a realtime environment, a system must be able to guarantee that it will lock a process in memory to reduce latency for data access, instruction fetches, buffer passing between processes, and so forth. Locking a process's address space in memory helps ensure that the application's response time satisfies realtime requirements. As a general rule, time-critical processes should be locked into memory. This paper describes the items about “Memory Locking and Unlocking Functions”and“Memory Locking in multiprocesses environment”in a realtime environment.

Abstract:The STAP of the forward looking airborne radar (FLAR) is studied. A scheme is presented, which is processed by the way of STAP combined with using multiple staggered medium pulse repetition frequencies (MPRFs). In addition, the selection of PRFs is further discussed to make the scheme more available for FLAR. The performance and range/velocity blind zone of FLAR are also investigated by using 3-C approach. The experimental simulation results suggest that the scheme can improve the detection performance in all interesting ranges for FLAR.

Abstract:The impedance and radiation characteristics of ridged horn are calculated by using the FDTD method with PML absorbing boundary condition and CP method on treatment of curve PEC boundary and slot between ridges. The amplitude and phase for antenna field are given, and results show that this method is perfect.

Abstract:To meet the requirement of precise GPS positioning in vehicle management system, and also to consider the development in the future, this paper introduces differential GPS projects. Vehicle route matching technique is presented, aiming at the unreliability of the above-mentioned project. Our experiments proved that vehicle route matching technique can not only improve positioning precision, but also avoid the chaos in vehicle's display on the electronic map.

Abstract:After studying the correlation matrix of 2D harmonic signal, we present a new algorithm called “matrix pencil algorithm for 2D harmonic retrieval problem”(MP2D).This algorithm is highly efficient in computation because it does not have to solve the roots of 2D polynomial or search for the peak of 2D frequency space. The simulation experiments show that this algorithm has high precision for 2D frequencies estimation and low sensitivity to noise.

Abstract:Based on the fact that the Faddeeva algorithm can practise various matrix manipulations and can be mapped easily into a systolic architecture, an approach of the systolic implementation on Kalman Filtering based on the Faddeeva algorithm is presented. Moreover, two architectures of processors were developed. The analysis results show that these two architectures are efficient, regular and expandable.

Abstract:The recursion formulas of elements current for series-fed microstrip arrays are presented by applying the lossy transmission line theory. The results of gain and patterns were compared with experiment's results. The identity of both shows that it is necessary to take microstrip line's loss into account to obtain accuracy patterns. The relations between the number of microstrip array's elements and gain are also analyzed and the curve is presented.

Abstract:This paper first points out the errors affecting the performance of ultra wide band quadrature demodulation receiver.Then a method for real time correcting the amplitude and phase errors of UWB quadrature demodulation receiver using 2PFIR filters is presented，according to the high speed，large data quantity of UWB. An algorithm designing the complex coefficients 2PFIR filters is alsooffered，followed by a practical example.

Abstract:Considering the complexity and non-perfection of the stability analysis in fuzzy control systems，we used the view of information theory to study this problem. Based on Lyapunov stability analysis law，the problem is deeply researched and discussed by introducing the concept of information entropy. Through considering comprehensively the dynamic characteristic and stability boundary of fuzzy control systems， the stability definition of fuzzy control systems is given，and a new stability sufficient condition of fuzzy systems is proved by strict mathematical deducing.

Abstract:A new method to perform the apportionment of system reliability with Genetic Algorithm（GA）and Fuzzy Logic（FL）is presented. We employed FL to model the uncertainty Within the limits and designing aims during the initial stages of the conceptual design of engineering system， and use GA to find the solution for it. This method boosts the efficiency and precision of system reliability apportionment through exerting the ability of GA&FL. The simulation result shows the performance and feasibility of the new method.

Abstract:A robotic visual servo control based on active contour is presented, which combines the active contour with the image optical flow for tracking image contours related to the object of interest. The active contour provides the position information of the object to control movement of the camera. For accomplishing the robotics tasks such as positioning and tracking, by using the proposed method the real-time constraints as well as the requirements of accuracy and robustness are fulfilled. To verify the potential of our approach, we carried out several experiments.

Abstract:Aiming at the multi-axes vibration control with random exciting, starting from the supposition of multi-input and multi-output linear system , the paper deals with equalization control method, exciting spectrum matrix simulation and control system design. Based on the study, the paper proposes a closeloop control arithmetic for multi-axes vibration control with random exciting. The simulating calculation proves that this arithmetic is valid. Finally, the paper offers a scheme of the control system including hardware and software.

Abstract:This paper introduces a new method of optical non-contact measurement, by using four beams of laser and position sensitive detector to measure position and angles, so as to determine position's posture of the motional object at some instant. The analysis and research on the internal composition of the system and its signal processing are made. The experiment proves that the system has many advantages: high accuracy, good restability, fast response, wide measurement range, composition compactness and low cost. So, this measuring system has a good future to apply in industry because of its attractive performance/ cost ratios.

Abstract:The shafts with inner and outer cones is applied widely to aviation machine, but the definite calculating approach of their rigidity isn't given in current machine design manuals. The problem to be solved in calculating bending rigidity of shaft parts with computer is discussed, and an approach of calculating bending rigidity of shafts with inner and outer cones is introduced, and implemented by ADS developing tools in Auto CAD.

Abstract:The background of the emergence of chaos control is reviewed. The OGY's method is introduced and some important developments in the last decade are briefed. Moreover, the direction of its development and possible difficulties are predicted.

Abstract:This paper introduces the basic principles and steps of the Monte Carlo Methods used in the electron transport calculation. The electron transport process is simulated by “condensed history” Monte Carlo method. The electron random walk path length is determined by the energy steps. For a single step, the electron energy loss is the total amount of the nonradiative (collisional) energy loss and radiative (bremsstrahlung) energy loss, the nonradiative energy loss in each step is sampled from Landau formulation, and the radiative energy loss and the production of bremsstrahlung photon is sampled from Bethe-Heitler formulation. The direction of electron at the end of each step is sampled from the Gouddsmit-Saunderson multiple scattering formulation. The Moller cross section is used for the sampling of the electron-electron scattering. Finally the electron transport in the space used aluminum alloy, and plane materials is calculated and the results are presented.

Abstract:Numerical distributed transfer function method is applied to planar optical waveguides. By using scalar variational principle, the numerical transfer function equations are derived. Then problems are solved in the form of state space. Infinite elements are introduced to reduce the amount of computation. This is more reasonable in the near cut-off case. Application and numerical examples are given and compared with several other methods which show the advantage of this method on planar optical waveguides with either step or graded refractive index profile.

Abstract:The time-dependent method&LU-SGS implicit scheme has been used to solve 2D compressible Navier-Stokes equations which are preconditioned and simulate the driven cavity flow field at different low Mach numbers and different Reynold numbers. To apply the time-dependent method to simulate the flow field at low speeds validly and accelerate the convergence rates, a matrix called preconditioning matrix has multiplied the time-derivative terms of Navier-Stokes equations. This is known as preconditioning. Convergence rates are accelerated for a certainty, while providing solutions are identical to those obtained without preconditioning methods. The results are compared with available data.

Abstract:In plane dynamic loading experiments, the velocity of flyer and state of impact are key parameters of loading condition. A technique of electric pins for measuring the above parameters is designed, aiming at deducing a real velocity of flyer and slant of impact from local records of pins signs through a certain arrangement of the pins. The method has been used in experiments of shock activating Si₃Ni₄ powder materials, and the results are satisfactory.

Abstract:Three kinds of samples YBCO(123 phase)have been prepared by solid state reaction method. The samples were radiated by high power microwave, then the critical current density J_C was measured. The experimental results show that proper microwave radiation can improve the critical current density J_C of samples, samples radiated once in comparison with non-radiated samples, the value of J_C increases one order.

Abstract:Using Low-molecular organosilazane[(CH₃)₂NHN]_n as precursor, which is reaction product between (CH₃)₂SiCl₂ and N₂H₄, Si/C/N ultrafine composite powder was synthesized by vapor reaction decomposition. The pyrolysis mechanism and reaction mechanism of gas-phase precursor under H₂, NH₃ atmosphere and the influence of the pyrolysis conditions(pyrolysis temperature, gas flowing rate, H₂/NH₃ ratio) on the morphological characteristics, the composition of the powder were discussed. Nano-powder is amorphous with 16.49%～26.75% Nitrogen, the least particle size about 40 nm.

Abstract:The factors, including condutive agents, additives, adhesion agent, activeation agents and pressure processing of negative electrode for hydrogen storage battery, were studied by orthogonal test. The optimum conditions of negative electrode for hydrogen storage battery were obtained. The properties of hydrogen storage battery show that discharge capacity, cycle life, self-discharge and macrocurrent charge-discharge are excellent.

Abstract:This paper presents the determination methods of the evolved NH₃ from thermal analysis by chemical absorption-photometry (CAP) and combined thermogravimetry-gas chromatography (TG-GC).The two methods are simple, rapid and exact. A recovery within 100±6% is generally obtained. The applicable range of these methods is compared.