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Twig query, also known as tree pattern query (TPQ), is considered as the core operation of XML data queries. However, a complex XML query described by XQuery often cannot be represented by a single basic TPQ. Aiming at XQuery language, this paper presents a multi-layer tree pattern representation method, named MTP, and a matching algorithm MLTwig, which can effectively use intermediate results of outer query to match inner tree pattern in MTP based on a novel data structure, WTree, thereby saving time and space. Experimental results show that this algorithm can improve the processing efficiency for XQuery expression which can be represented by MTP.

A new passive target motion analysis (TMA) based on method a single seismic-filed vector sensor is designed using pitching angle and multi-path delay is studied. The state equation and measurement equation are established and analyzed systemically by improvement particle filter based on the measurements of both bearings and time delay that are collected by the sensor. The Monte Carlo simulation experiment results demonstrate that the algorithm has some advantages of fast convergence, high precision and stability.

Polarization filtering is an effective method to process the ocean bottom multi-component seismic data but distort signal amplitude and phase. To solve this problem, a method of polarization filter based on oblique projection operators (OOPF) in process of ocean bottom multi-component seismic data is proposed in this paper. First, we compute polarization parameters based on singular value decomposition (SVD); secondly, an oblique projecting polarization is construct by polarization parameters, finally, the simulation and experiment data results and indicates that the proposed method effectively processing the ocean bottom multi-component seismic.

According to the non-stationarity characteristics of the vibration signals from reciprocating machinery,a fault diagnosis method based on empirical mode decomposition,Lempel-Ziv complexity and support vector machine(SVM) is proposed.Firstly,the vibration signals were decomposed into a finite number of intrinsic mode functions(IMF), then choosed some IMF components with the criteria of mutual correlation coefficient between IMF components and denoised signal.Thirdly the complexity feature of each IMF component was calculated as faulty eigenvector and served as input of SVM classifier so that the faults of machine are classified.Practical experimental data is used to verify this method,and the diagnosis results and comparative tests fully validate its effectiveness and generalization abilities.

Cellulose fibers were chemically modified on surface by acrylamide polymerization and glutaraldehyde crosslinking. The chemical and morphological structures of modified cellulose fibers were investigated with X-ray diffraction, FTIR spectra, and scanning electron microscopy (SEM). The crystalline conformations of the cellulose fibers were slightly changed in polymerization and crosslinking process. The wet strength of modified cellulose fibers was improved. Appreciable difference between the surfaces of native and modified cellulose fibers was observed from SEM images.

Due to the rapid development of manufacturing technology, high-speed high-resolution data acquisition system has been widely applied in plenty of engineering fields, such as radar, environmental surveillance, mass spectrometry, etc. In order to satisfy the increasing requirement, we present the design of a high-speed data acquisition system, which is mainly composed of high-speed time-interleaved analog-to-digital converter, high data throughput interface based on 10 gigabit Ethernet. The detailed design and realization of each module are presented. Finally we test and analysis the performance of the ion signal acquisition system, and the results show that the system performs fine speed, high precision and stability.

The performance of the Ocean Bottom Seismometers (OBS) in seismic wave field measurement is vital to seismic exploration. In order to improve the performance of OBS, we have been developed a new Ocean Bottom Seismometer based 3-component MEMS accelerometer sensors. In order to sample seismic data synchronously, we have been designed multichannel A/D unit under the control of MSP430.We also are involved in a handle and sophisticated equipment allows to storage sampling data in the SD card module. The system based MEMS sensor are compared with conventional analog moving coil geophones, the result shows that the new measurement system with the advantage of high dynamic range, low noise and anti-jamming that suit for the high resolution seismicity information. The paper show that the new digital OBS using MEMS accelerometer will replace the tradition OBS in oil exploration, scientific research and seabed surveys.

In this paper, we propose a revolutionary communication paradigm—Wireless Cognitive Sensor Network (WCSN) — to solve these problems. We analyze the incentives to introduce WCSN in smart grids and review the main research work with respect to Byzantine attacks in wireless cognitive sensor network. Furthermore, we provide some preliminary discussions on Bayesian game and wireless cognitive sensor network. More importantly, we propose a Bayesian game model for the Byzantine attacks of wireless cognitive sensor network in the smart grid and present a detailed equilibrium analysis of the interactions between malicious secondary users and honest secondary users. Analysis results demonstrate that rather than focus on penalties, regulators would be wise to ensure that the gain from challenging is significant and the cost of challenging is small, as this reduces the probability of sending false readings.

Wireless sensor networks have been extensively deployed in the electric power systems for sensing, transmission and control, which provide more opportunities for wireless low power radios to operate. As the next generation electricity system, the smart grid should possess the capability to transmit reliable and real-time information to the control centers of the utilities. In order to solve the issues such as heterogeneous coexistence, spectrum scarcity, tremendous data processing and Security guarantees, revolutionary communication architecture is urgently demanded. In this paper, after analyzing the hierarchical structure of smart grid and illustrating the principle of WCSN in smart grids, we propose the security architecture of wireless sensor networks based on cognitive radio for smart grids, which can be used as a reference to design and develop the Wireless Cognitive Sensor Network (WCSN) security schemes in the electric power systems.

The natural vegetable dye grape seed extract (GSE) was applied on the direct dyeing of lyocell knitted fabric. By changing the dyeing condition, the modified process was derived after evaluating various fastnesses of the dyed fabric. The direct dyeing method should be under the condition of GSE’s concentration 5g/L, bath preparation temperature 80°C, pH value 3, bath ratio 1:30, dyeing time 60min. The color is very sensitive to pH and GSE’s concentration. The rubbing fastness, washing fastness and light fastness is good, the acid perspiration fastness is better than the alkaline perspiration fastness.

This paper introduces the design and realization of a multi-channel high-speed waveform generator based on FPGA, Which consists of the high-speed clock generator, the high-speed high-precision digital to analog converter, multi-stage pipeline accumulator and high-speed small signal conditioning. At last, it gives some simulation. The results show that the output signal type of this waveform generator is rich, and the maximum output frequency is 80MHz. The waveform generator can be used in the fields which require multi-channel high-speed signal, such as phased array radar.

Limited studies exist related to the siro-spun spinning of flax ( Linum usitatissimum L.) and cotton (Gossypium hirsutum) blends. The purpose of this study was to determine the influence of various siro-spun processing parameters, including twist factor, space between two rovings and specification of traveler, on yarn qualities, such as yarn hairiness, tenacity and evenness. Results show that both specification of traveler and space between two rovings significantly influenced yarn hairiness and evenness, and heavier traveler and greater space led to decreased hairiness, but bad evenness. Twist factor influenced yarn evenness highly significantly, and smaller twist factor led to worse yarn evenness. Results also indicate the optimum levels of siro-spun process parameters as follows: twist factor αm = 150, space between two rovings 8 mm, traveler Fo 5/0. In relation to the general ring-spinning yarn, the siro-spun spinning yarns had decreased hairiness, little increased tenacity and similar evenness.

To study the blade-wake interaction of vertical axis tidal turbine (VATT)，particles were placed in the flow field to trace blade wake during numerical simulation. Numerical simulations were conducted utilizing Euler-Lagrange model. In the simulations, the continuous phase was solved by Reynolds-averaged Navier-Stocks(RANS) equation combined with SST turbulence model and the particle trajectories of the dispersed phase were determined by momentum equation. Numerical results of predicting instantaneous blade forces and blade wakes showed good agreement with the test data. The model was also compared with previous classic free vortex model (V-DART), vortex method combined with finite element analysis (FEVDTM) and 2-D vortex panel model (VPM2D). It showed that the present model was much better than the former.

Added sarcandra glabra extracts into cellulose viscose solution, make the two blends together to spin, and get functional viscose fiber with the nature antibacterial function. The test result shows that mixed sarcandra glabra extracts has no bad effect on the basic mechanical properties of the viscose fiber and the viscose fiber has the good antibacterial performance.

Keeping deposition temperature and oxygen pressure constant at 300°C and 4.0×10-2Pa, respectively, deposition of ZnO thin films with c-axis oriented (002) hexagonal wurtzite crystal structure was achieved by pulsed filtered cathodic vacuum arc deposition (PFCVAD) system at various negative substrate bias on Si(100). The surface morphology was characterized using AFM, and crystallographic structure was studied by means of X-ray diffraction. Based on the biaxial strain model, Strain properties of the ZnO films were investigated by calculation from XRD data. The calculated results revealed that the as-deposited ZnO films exhibited only tensile stress and the tensile stress increased with the elevation of the negative substrate bias. Occurrence of the tensile stress is suggested to be the result of relatively high deposition temperature and the improved deposition rate by elevating the negative substrate bias. It provides a potential method to control the intrinsic stress in the ZnO films by modulation of deposition temperature and the negative substrate bias of PFCVAD system.

The half-direct-drive transmission is conducted for the transmission system of tidal current power stations using a small speed-up ratio of planetary gearbox between turbine and generator. A design model is developed for the optimization of the planetary gear transmission system. And a mixed genetic algorithm is applied on the basis of fundamentals of genetic algorithm to carry out the optimization. From the example calculation, a better design scheme is obtained by the optimization.

Dry and wet oxidation silica films doped with silicon ions were prepared using metal vapor vacuum arc (MEVVA) ion source implanter. The does of Si ion beams were kept constant at 3×1016 /cm2 and the energy varied from 42KeV to 70KeV. Five photoluminescence (PL) bands at the wavelength of 560nm, 580nm, 620nm, 650nm and 730nm have been observed at room temperature in all samples. The results of XRD showed none of Si nanocrystals were formed in the as-implanted silica films and originations of the PL bands were defects introduced by implantation. The 560nm PL band originated from oxygen surplus defect small peroxy radical (SPR), whereas the PL bands which ranges from the wavelength of 620nm to 730nm were attributed to non bridge oxygen hole center (NBOHC). Elevating implantation energy resulted in intensity increasing of 560nm PL band of dry oxidation samples but had inverse effects on wet oxidation samples. Influence mechanism of implantation energy on the defect photoluminescence was discussed in this article.

In this paper, an improved ACA (IACA) is used for tuning PID parameters. Firstly, the mathematical representation of conventional digital PID controller is deduced. Then genetic algorithms (GAs) and ACA are described. Thirdly, a PID controller based on IACA is designed. Computer simulation is performed for the proposed IACA-based PID controller finally. The results show that the proposed method could search the optimization PID parameters efficiently. The tryout of the designed controller in a paver walk system driven by valve-controlled motor runs well up to present.

Methods of modeling stress strain curves for nonlinear stress analysis are discussed in order to obtain comparable results between different finite element analysts and between different versions of designs. The most common method for modeling stress strain curves is to use Ramberg- Osgood equation. For materials with significant discontinuous yielding, Ramburg-Osgood approximation leads to some problems near discontinuous yielding point. Discontinuous yielding occurs when sudden onset of plastic deformation associated Luders band takes place in a uniform test sample. For engineering structures and machine components, the propagation of Luders band may not occur in deformation process because of non-uniform stress distribution caused by stress concentration, complicated loading condition etc. A modified Ramberg-Osgood method for modeling stress strain curve is proposed.