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Photomultiplier tube (PMT) receiver is a promising solution for long-distance underwater wireless optical communication (UWOC) due to its characteristics of high gain, low noise, and large receiver area. However, the complex underwater environment leads to the dynamic change of the received optical intensity and impacts the stability and reliability of UWOC system using PMT. In this work, the bandwidth limitation and performance degradation of UWOC system caused by PMT saturation is experimentally observed and characterized for various optical intensity and PMT gain. A low-cost, high-integrated, and small-volume receiver control system and relevant adaptive control strategy are proposed to improve the stability and reliability of UWOC system by dynamically adjusting the received optical power and PMT gain according to the detected optical signal. The experiment results show that the dynamic range of UWOC received optical power can be extended to 68 dB (−63 dBm∼5 dBm) for 100 Mbit/s OOK modulation based UWOC system.

Seismic deconvolution plays an important role in the seismic characterization of thin-layer structures and seismic resolution enhancement. However, the trace-by-trace processing strategy is applied and ignores the spatial connection along seismic traces, which gives the deconvolved result strong ambiguity and poor spatial continuity. To alleviate this issue, we developed a structurally constrained deconvolution algorithm. The proposed method extracts the reflection structure characterization from the raw seismic data and introduces it to the multichannel deconvolution algorithm as a spatial reflection regularization. Benefiting from the introduction of the reflection regularization, the proposed method enhances the stability and spatial continuity of conventional deconvolution methods. Synthetic and field data examples confirm the correctness and feasibility of the proposed method.

Background The China Spallation Neutron Source (CSNS) accelerator consists of an 80 MeV H- LINAC, a 1.6 GeV rapid cycling synchrotron (RCS) and two beam transport lines. The uncontrolled beam may permanently damage the components or lead to very high residual radiation dose along the beam line. So the equipment protection must be deliberately designed and implemented. Purpose The machine protection system (MPS) protects components from being damaged by the beam. The response time requirement for the CSNS MPS is less than 20 ms, so the PLC (programmable logic controller) was adopted to implement the interlock logic. Methods The MPS was implemented as a two-tier architecture system, and developed through utilizing PLC and Experimental Physics and Industrial Control System (EPICS) software toolkits. The application logic was taken into careful consideration during the implementation stage. An embedded CPU module can function as an IOC accessing PLC I/O modules through the sequence CPU, with an embedded Linux operation system. Results The interlock logic and heartbeat functions were tested with all functions ok. Time consumption has been measured thoroughly since the important requirement, which is around 15 ms to stop the beam. Conclusions MPS was completed in Sep. 2017 and then put into operation. It has been operating smoothly for more than 3 years. MPS has played an important role in every stage of CSNS’s commissioning and operation and achieved high reliability during the user’s experiment operation. The accelerator recently runs stably with low equipment failure.

Modern ships are developing in the direction of intelligence, large-scale, and complexity. At the same time, operators have put forward higher requirements for their general quality characteristics and comprehensive maintenance support. As one of the key technologies of operation and maintenance, fault prediction and health management (PHM) have also received greater attention. This paper analyzes the development, research and application status of ship related technology, summarizes the limitations of the current application, and designs the architecture and functions of PHM system to provide reference for the follow-up system design, and finally analyzes the future development trend.

Firstly, the parameter analysis of the double-cylinder permanent-magnet eddy current coupler is carried out by using Maxwell finite element analysis software. Considering the theoretical and practical situation, the relationship between the main structural parameters and the transfer torque is determined. Then, in order to reduce the calculation cost of the subsequent optimization, BP neural network and support vector machine are used to establish the nonlinear model between the main structural parameters and the transfer torque. Comparing the two methods, it is found that the SVM method is superior to the BP method in predicting performance and running time. Finally, a test system is built to verify the accuracy of the SVM nonlinear model.

The key directions for the automation, intelligence and integrated development of space launch have been very clear. Within the scope of C3I systems, professional automation system, ground handling system, research is conducted on the overall technical architecture of the space launch information integration, including: (1) Research on technical specifications system to promote the systematization and consistency for technical specifications at each level of access, transmission, processing and application; (2) Research on system functional architecture, highlighting the unified terminal access, unified transmission carrying, unified basic application and unified information interaction; (3) In view of the future development direction of space launch informatization, research will be carried out on relevant information guarantee technologies for remote command operation, automatic detection and diagnosis, wireless object connection and unattended launch tower.

Whether sensors important to safety could work normally is the primary factor that affects the safety function of nuclear power plants. Based on the redundant characteristics of sensors important to safety in nuclear power plants, a fault diagnosis method combining hardware redundancy and discrete wavelet transform is proposed. Finally, in accordance with the design requirements for the DCS of nuclear power plant, combined with the relevant laws and standards, a hardware implementation scheme for the diagnosis device, is given as part of the DCS.

Orthogonal frequency division multiplexing (OFDM) is a kind of high spectrum efficiency and ability to resist multipath fading of multi-carrier modulation technology, that is widely used in communication, and one of the core technology of the fourth generation of mobile communication. The purpose of underwater communication pattern recognition, is to recognize the modulation pattern from the received underwater acoustic communication signal. This technique has great influence on underwater acoustic communication interference spectrum monitoring, signal receiving and acknowledgment, communication management. In this paper, we have studied the method of cyclic cumulants and autocorrelation characteristics for OFDM signal modulation recognition and detected the signal in multipath condition. The results showed that autocorrelation characteristics still a best approach for recognizing the OFDM modulated signal.

There are many modulation formats (such as FSK, PSK, ASK) in the process of underwater acoustic communication, and the task of the signal modulation identification is to distinguish the format that used from signals which received from acoustic communication. This technique for communication management, such as underwater acoustic communication spectrum monitoring, interference listening and signal confirmation, is of great significance. The cyclic cumulant is served as the characteristics of the signals, and the signal modulation formats is classified by support vector machine. We use the method to carry out the simulation experiment in alpha stable distribution noise environment and the sea experiment. The results show that the method is reasonable and effective.

Based on the finite element method, Finite cell model of the stray current transmission net was established, and the mathematical expression of track potential, track current and stray current was proposed in the DC traction power system. And the analysis model of track to earth insulation defect was built. Simulated and analyzed the stray current distribution under track to earth insulation well and defect. Analysis shows that stray current is almost leaked out the point after insulation defect occur, and the total amount of stray current and the maximum value of track to earth potential will be increased. current and potential are effected by insulation defect.

In this paper, we investigate the consensus problem of multi agent systems based on the discrete-time general linear model with actuator saturation. A new family of distributed parametric low-and-high gain control protocols is provided, and such control protocols rely on the discrete-time Parametric Algebraic Riccati Equation. Furthermore, the convergence results are also given as consensus function sequences. Finally, an illustrative example shows that the low-and-high gain control protocol is effective for the consensus problem of the general linear multi agent systems with actuator saturation.

This paper provides anew strategy for study of Structural Health Monitoring, and discusses establishment of structural safety monitoring system based on the structural destroyed modes and data corr...

Regularized Orthogonal Match Pursuit(ROMP) is widely applied as a signal reconstruction algorithm.Despite its high efficiency,ROMP requires the prior knowledge of signal sparsity,and would be unstable if the sparsity level is improperly estimated.To overcome this drawback,a weak selection strategy was introduced to adaptively determine the number of atoms and the candidate atoms by estimating the relevance between iterative residue and measurement matrix of the original ROMP algorithm.Thus,an optimal atom set for the signal reconstruction procedure could be selected from the candidate atoms according to the regularization principle.Numerical results demonstrate that the proposed method outperforms other greedy algorithms with 0.5~1.5 dB higher PSNR and much lower MSE.

This paper proposes and simulates a novel all-optical error-bit amplitude monitor based on cross-gain modulation and four-wave mixing in cascaded semiconductor optical amplifiers (SOAs), which function as logic NOT and logic AND, respectively. The proposed scheme is successfully simulated for 40 Gb/s return-to-zero (RZ) signal with different duty cycles. In the first stage, the SOA is followed by a detuning filter to accelerate the gain recovery as well as improve the extinction ratio. A clock probe signal is used to avoid the edge pulse-pairs in the output waveform. Among these RZ formats, 33% RZ format is preferred to obtain the largest eye opening. The normalized error amplitude, defined as error bit amplitude over the standard mark amplitude, has a dynamic range from 0.1 to 0.65 for all RZ formats. The simulations show small input power dynamic range because of the nonlinear gain variation in the first stage. This scheme is competent for nonreturn-to-zero format at 10Gb/s as well.

A network-based Virtual Private Network (VPN) architecture by using fundamental routing mechanism is proposed. This network is a virtual overlay network based on the relay of IP-in-IP tunneling of virtual routing modules. The packet format employs the encapsulation of IPSec ESP (Encapsulating Security Payload), an impact path code and an extended DS (Differentiated Services) code to support multi-path routing and QoS. Comparing with other models of VPN, this network system can be deployed in the current network with little investment, and it is easy to implement. The simulation result shows its performance is better than the traditional VPN system of black box mode.

A component level designing method based on object-orientation is presented in this paper, which supports re-usable 3D graphics. The performance, the designing method and primitive growing algorithms are analyzed. A component is realized which supports the 3D virtual scene, modeling, and motion simulation. The athletic hierarchical linkage relation and data structure are described. Under the virtual environment, numerical control milling machine modeling and motion process simulation are applied successfully.

Beam splitter,as a kind of linear optics instruments,has many applications such as in quantum optics and quantum information,including the preparation of nonclassical quantum states and entangled state representation.In Heisenberg picture,on the one hand,the relation of input-output of beam splitter can be easily obtained.Especially for the multicascaded beam-splitters,the input-output relation can also be directly obtained by the input-output relation of single beam splitter.On the other hand,we often need to calculate the probabilities of detecting photon number in many cases,thus we need to turn into Schrdinger picture for simplifying our calculation.Based on the equivalence between both pictures,the relation between transformation matrixes connecting these two pictures is derived.That is to say, the transform matrix corresponding to the Schrdinger picture can be obtained by transposing the transform matrix in Heisenberg picture.This concise relation constructs a bridge connecting two pictures and simplifies our calculation in the Schrdinger picture rather than step by step.Using the relation between transform matrixes of both pictures and combining the technique of integration within ordered product of operator,we further consider the coordination representation,normally ordering form and exponential expression of single beam-splitter.Then we further examine the coordination representation,normally ordering form and exponential expression of two-cascaded beam-splitters.As a generalization,the method is extended to the case of multi-cascaded beam-splitters.These investigations provide an effective way to prepare multi-mode entangled states and qubit states.In addition,a general method is shown of obtaining the total operator and its normally ordering form as well as Schmidt decomposition of the linear systems consisting of beam-splitters.As applications,2-cascaded beam-splitters is used to generate a new quantum mechanics representation and prepare the qubit states with the help of conditional measurement.The Schmidt decomposition of three-mode entangled state representation can be directly obtained by the coordination representation of 2-cascaded beam-splitters,which shows the property of entanglement.In addition,based on this representation we can clearly see that when the input states of first beam splitter are two coordinate states,the output states cannot be entangled.This implies that although the coordinate states are nonclassical,the entangled state can not be prepared either.The new proposed quantum mechanics representation will be further used to investigate the optical transformations,including wavelet transformation,Fourier transform,fractional Fourier transform,et al.Therelevant discussion will be our aim in the future research.

The electrocardiogram (ECG) has broad applications in clinical diagnosis and prognosis of cardiovascular diseases. The accurate description for the question how the ECG come from the cardiac electrical activity is helpful for understanding the corresponding relation between the ECG waveform and cardiovascular disease. Experience is the primary method of studying the ECG, but the computer simulation method makes it more convenient to explore the effect of given factor for ECG waveform. Cellular automaton is a simple and effective computer simulation method. However, the cellular automaton model considering the main structure of the heart is not yet established. Therefore, we propose a cellular automaton model for the ECG considering the atria, the ventricle, and the ventricular septum. With this model, the conduction of the myocardial electrical activation is simulated by following the field potentials under healthy and diseased conditions, and the underlying mechanisms are analyzed. Through the computer simulations and analyses the results are obtained as follows. First, the conduction process of the electrical signal in this model is the same as that in the real heart. Second, under the healthy conditions, the behavior of the field potential appears as normal ECG, in which the P wave and the QRS wave group come from the depolarization of the atria and ventricle, respectively, on the other hand, the T wave and J wave come from the repolarization of the ventricle. The computer results support the conclusion that the J wave appears just because the existence of the notch in the epicardial transmembrane potential curve. Third, the endocardium ischemia conditions result in the T wave inversion. The mechanism is that the action potential duration of the ischemic endocardial cells is shorter than that under normal conditions, which makes larger the transmembrane potential gradient between the endocardium and the subepicardium, and then contributes a more negative value to the field potential. Fourth, the epicardium ischemia leads to the higher T wave, and this is because the shorter action potential duration of the ischemic epicardial cells brings in a larger transmembrane potential gradient between the epicardium and subepicardium, which makes the field voltage larger. Fifth, the T wave appears earlier under the through-wall ischemia. The action potential durations of cells of the endocardium, the epicardium, and the subepicardium all become shorter under the through-wall ischemia, then the repolarization processes of all of these three walls are ended earlier, which leads to the earlier T wave. The cellular automaton model proposed in this paper provides a reference for the further study of ECG.

A new method is introduced for double sensors bearings-only association based on target motion state characteristics. Usually, acoustic sensor can only take a bearing detection at passive method. So, when two sensors detect passively a sound source respectively, we need to do a association judgement whether sources are from the same target. It is difficult to associate only using bearings. First, we can make a hypothesis that they are the same one, and establish “target” motion model. Then, we can estimate “target” motion parameters through the bearings detected by two sensors, and extract the motion state character. Last, we calculate the comparability with the actual target, and make a determination that the “ target” is true or false. As a simulation result, the method can achieve double sensors bearings-only association.

This paper introduces the functional structure and framework of a universal GML schema-based parser. A valid algorithm for parsing various application schemas of GML is discussed in this paper. By making researches on intrinsic mechanism of core schemas, a set of grammatical and semantic parsing APIs are established to implement GML data parsing. The APIs would serve as the foundational operation collection for universal GML schema-based parsing engine.

Geometric distortion is important in the research of image geometric processing. This paper introduces a unique technique for image processing based on low-altitude UAV (Unmanned Aerial Vehicle) and accordingly generating the DEM and Digital Orthophoto. Through the UAV image Orthorectification and the regional network of radio beam method for adjustment of the whole deal, and then analyzes the impact of accuracy of geometric correction factors. Experiments proved the scheme is reliable which arrange ground control points more dense around the peripheral field.

The space thermal environment will affect measurement accuracy of star sensor. A model which can be used to analyze the thermo-optic effects on star sensor is built using the software ANSYS, the forward ray tracing algorithm, and aspheric polynomial algorithm. In order to make the aspheric polynomial fitting algorithm suitable for more surfaces and control the numerical accuracy of this algorithm, the algorithms that translating the coordinates and scaling the coordinates are added in this algorithm. The measurement error can be calculated using the model when the temperatures of the optical system change in a uniform value. Then several simulations are done when the temperatures of the optical system increase in different values. And other simulations are done on the condition that the location of the lens in the drawtube is different. The results showed that: the bigger the temperature difference is and the farther the lens is from its fixed surface on the satellite, the bigger the measurement error of the star sensor will be.

This article discusses the development of monitoring system about the security situation in coal production and coal mining. In order to solve the problem of coal mine monitoring systems and self-management of coal enterprises, Adopt the Socket communication mechanism based on TCP protocol, design the Real-time monitoring and development of a WEB-based remote coal mine gas monitoring system. The test result of this system indicates that it works normally and reaches the design goals, and it has been successfully applied in a coal mine in Shanxi province.

The signal processing elements and working course of MTI radar are analyzed in this paper, and theory research is also done to the element and performance of double canceller. Aiming at the Gaussian power-spectral clutter with differ velocity value and variance, this paper calculates the performance of MTI system quantitatively and the corresponding improvement factor of anti-passive jamming is achieved, the performance of MTI radar is estimated synthesized.

The single event effects (SEE) characteristic and hardening techniques of CMOS SRAM with sub-micron feature size are studied in the paper. After introducing the relationship SEE with the structure of memory cell, the rate of read-write, the feature sizes and the power supply, the SEE hardening techniques for the COMS SRAM are given from tow aspect: device-level hardening techniques and system-level hardening techniques. Finally, an error detection and correction (EDAC) design based on high reliability anti-fused FPGA is presented, this design has special real-time performance and high reliability, and has been adopted in a space-bone integrated processor platform, which works well in all kinds of environmental experiments.

To meet the accuracy and efficiency requirements in motion estimation, an adaptive diversity rapid search algorithm based on variable size block is proposed in this paper. Two kinds of search algorithms, diamond search and three-step search, are applied to different sub-blocks of the same macro block. The disadvantages of single search strategy are overcome by the algorithm diversity and the similarity of the sub-blocks, which reduce search points obviously. This paper also analyzes and researches XVID, which is one of the open source software of MPEG-4, and gives the optimization design of transporting XVID into ADSP-BF533 processor to achieve real time MPEG-4 encoding. The experimental results show that the MPEG-4 coder implemented in this paper can reach the requirement of real time coding.

In this paper ,the criteria for convolutive blind source separation(CBSS) is analyzed. We prove that the output stochastic process’s spatial independence is the necessary and sufficient condition for achieving separation. Using the definition of spatial independence, we converted this condition into minimum mutual information of output variables. Then we optimize this criteria with the method of steepest descent and get the recovered sources. Computer simulations show that the conclusion of this paper is correct.

To select optimal processing parameters for Rapid Prototyping (RP) and improve the product efficiency, a visual modeling and simulating method for laser action area in RP was proposed. The SolidWorks' API (Application Programming Interface) functions were transferred by the VB (Visual Basic) to program the system. This method could carry out each simulating treatment in processing for various slicing schemes, and it realizes the visualization of rapid prototyping simulation-results in SolidWorks. By analyzing and optimizing the results, a set of optimal parameters was obtained. Thus, it improves the processing efficiency as well as the accuracy and decreases cost.

The previous study of pattern discovery in storage systems focus on sequential pattern (SP) mining in lower level traces, but they don’t scale well to the application level. For patterns in application level are mostly composed of Contiguous Item Sequential Pattern (CISP) which are much simpler than SP, so it’s inefficient for the previous studies to mine CISP with clumsy SP mining algorithms. We propose a novel algorithm CISP-Growth which is more preferable for mining application level IO patterns. The CISP-Growth only scan the origin sequence in one-pass and make patterns grew among slices to avoid the inefficiency and information loss in C-Miner approach. The experiment result shows that the CISP-Growth outperforms C-Miner prominently in mining with real application IO traces and the simulation result also proves the effectiveness of CISP in application IO optimizations.

With the development of IT, mobile OA is getting more and more important in government, enterprises and institutions. The traditional OA solutions, for the defect of its combination with mobile equipment, limit the application to mobile OA. This paper introduces a typical representative frame of mobile OA system and puts forward a Web Service communication mode based on GPRS to resolve the data transmission between background server and terminal of this mobile OA system. The system has good expansibility and is easy to upgrade and maintain.

Different from the traditional road model, the model of road based on GML is adapt to the management fields on municipal road infrastructure. This article analyses the characteristic of the composing elements (road infrastructure) of road and the requirement of management.The author builds the spatial-attribute integration model for road infrastructure based on the GML Schema. At the end the author analyze the applied prospect of these models.

In this paper, the author introduces a new rotor position detecting method for the sensorless control of brushless DC motor (BLDCM). It applies a new circuit to get fundamental wave from three phase terminal voltage. A special switched capacitor filter is designed to achieve constant delay 90 electrical degrees. Since the phase lag is not related to the speed of the rotor, it needn't phase compensation. The filtered signal can be converted to six commutation signals for BLDCM just through zero-crossing comparator and decoder, so the detection circuit is simplified. The hardware-implemented system has low cost and high reliability, which is suitable for oil well detecting.

Frequency response masking (FRM) approach is an efficient technique to design a sharp-cutoff FIR filter. In this paper, a novel FIR filter design technique is studied based on frequency-response-masking approach. After introducing its principle, implementation structure and design method, its application in software defined radio (SDR) is stressed.

As more datapath stacks are integrated into system-on-chips (SOC), the datapath is becoming a critical part of the whole giga-scale integrated circuit (GSI) design. The traditional layout design methodology cannot satisfy the datapath performance requirements since it has no knowledge of the datapath bit-sliced structure. In this paper, we applied an approach of OpenTS (open tabu search) to determine the optimal datapath element ordering to minimize the track density, the wire length and interconnection delay. Experimental results show that the OpenTS is more efficient than the existing genetic and simulated annealing approaches.