Earticle

It has shown that the betweenness distribution of shortest path (SP) routing strategy on scale-free networks is exponential. Some nodes with great degree have higher flow. It is very easy to cause cascading failure when the node's flow exceeds its processing capacity. As a result, the service quality will fall. Utilizing the BA scale-free networks, we study the cascading failure between the minimum information path (MIP) routing strategy and the shortest path (SP) routing strategy. Then the tolerance parameters with upper and lower threshold are obtained by theory. The conclusion displays that the performance of SP routing strategy is slightly better than the MIP routing strategy when the network has little processing capacity. However, the value G of MIP rapidly growths and is close to 1, but the value of SP growths slowly with the process capacity increasing. In a word, the performance of MIP routing strategy is obviously better than the SP routing strategy. Therefore the robustness can be improved greatly by increasing the process capacity of some nodes under MIP routing policy.

In South Korea, the government has tried to deploy robotic systems as teaching aids in elementary and middle schools. However, the practical use of teaching assistant robots in classrooms has remained limited since teachers have experienced difficulties in using the legacy robot scenario editor to design their own class scenario. To provide flexible and on-demand class scenarios, teachers should edit class scenarios that are designed to achieve their class objectives. Since most teachers are usually not familiar with computer programming and robotics, it is important to have a class scenario editor that is easy to use without much needed expertise. We analyze the requirements for developing a class scenario editor for robot-aided classes by administering a questionnaire and conducting interviews with art teachers. From the user requirements, a class scenario editor for robot-aided classes can be developed and used by typical teachers without needing specialized expertise.

Elman neural network was utilized to accomplish mapping from vibrant acceleration space of unsprung mass to dynamic load space in order to identifying results of neural network can more approach dynamic changing course of air suspension during active controlling process of air suspension. The dynamic model of 1/4 engineering vehicle was established. Vibrant acceleration data and dynamic load data were got by simulation based on the dynamic model of 1/4 engineering vehicle. Vibrant acceleration data were selected to be input data and dynamic load data were selected to be output of Elman neural network. Elman neural network was trained by input and output data. Then, generalization of trained Elman neural network was tested as follows. Sine wave was selected as road input. When amplitude was selected as 0.1m and frequency was selected as 1 rad/s, data of identifying error rate within 30％ took 75.97％ in total data. When amplitude was selected as 0.05m and frequency was selected as 0.5 rad/s, data of identifying error rate within 30％ took 96.1％ in total data. Results indicated that Elman neural network possess better fitting ability on this situation. When amplitude was selected as 0.3m and frequency was selected as 2 rad/s, results indicated that identifying error rate decreased and identifying curve obviously separated with numerical curve. It is perhaps for the reason that more identifying data scale out the value boundary of trained data. Meanwhile identifying curve and numerical curve gradually approached and stabilized eventually. It demonstrated that Elman neural network can effectively approach dynamic changing course of air suspension.

This paper designs the feedback controller for the unstable Dutch Roll and severe kinematic coupling of the hypersonic vehicle at high angle of attack and large mach number. This paper deduces the mechanism of improving the stability of the Dutch Roll and illustrates the mechanism of restraining the kinematic coupling using controller based on the linear small perturbation equations. And an easy analysis is made about the signal of controller. Finally, the relational tests are conducted in simulations using controller. The simulation result shows that the controller can improve the damp of the Dutch Roll, weaken the influence of kinematic coupling, restrain the variety of sideslip and improve the equality of sideslip.

In this paper, the vertical aquarium is designed for the new energy management system is called as a vertical aquarium energy management system (VAEMS). This energy management system is the first time in the world. In the future, this energy will be played a vital role not only to save energy, also eco-friendly to the world. Generally, many thermal power plants are wasting the hot water and send to the sea. So that, the thermal power plant could be used in their process and after that will be wasted. This water can be used for the vertical aquarium at the temperature range of 210c - 300c, but this temperature is maintained for the vertical aquarium so that, we specially designed a 40 URT heat pump. The main concept of 40 URT is to reduce the maintenance and electricity cost. The 40 URT heat pump made with specially designed like tube typed evaporator, semi screw compressor, plated type condenser and expansion valve. The main concept of 40 URT heat pump inlet temperatures is 150c and outlet temperature is 650c used to less electricity. In this, the heat pump totally monitoring with sensors. The experimental results of the heat pump have been satisfied for the design of the aquarium.

Past research has produced various ramp metering approaches. Even so, the results of existing ramp control techniques are unsatisfactory due to the highly nonlinear property of the ramp control system. For improving the ramp metering performance and raising the ramp control accuracy, we propose a mixed approach of fuzzy logic control and proportional plus integral (PI) control for freeway ramp metering. We also employ a genetic algorithm (GA) to optimize the PI parameters in this paper. Furthermore, we apply a nonlinear control technique with a feedback loop to enhance system performance. Firstly, a first-order traffic flow model called hydrodynamic model is established, and the model characteristics are analyzed. Secondly, the control objective of the ramp metering system is defined by the mainline traffic density. Thirdly, a mixed controller of fuzzy logic and genetic PI is designed based upon this hydrodynamic model and in combination with a nonlinear control technique. The membership functions of the fuzzy logic control are triangular or Gaussian curves, and the numbers of fuzzy control rules are nine. Fourthly, optimization procedures of a GA for finding the best PI control parameters are given with details. Finally, the authenticity and effectiveness of the mixed controller are verified with Matlab software R2010a and also by VISSIM microscopic traffic simulation. Simulation results prove that this mixed control approach has better tracking performance and smaller density errors compared with the method of artificial neural networks. This mixed control approach, as well as the nonlinear control technique, provides a new idea for freeway ramp metering.

Many real-time applications use Internet as a media to transmit their data and need guarantee for correct data transmission and limited transmission delay. It requires efficient network traffic protocols to avoid or limit the level of congestion. In this paper we propose, design and analyze a Robust Delay Based Controller (RDBC) for traffic management on transmission control protocol (TCP). This controller is based on an output feedback controller for decreasing effect of delay and disturbance on performance of network. Linear Matrix Inequality (LMI) is used for optimize design objectives. The simulation results illustrate that the queue length in router reaches to desired value quickly with proposed RDBC. We use network simulator (NS2) to compare performance of RDBC with other AQM mechanisms Like RED, PI and PID. Queue length average and variance, bandwidth utilization, throughput and end-to-end delay are performance metrics that used for comparison.

Timing information of the alarm signal is rich after the electric power system goes wrong. It will diagnose the fault quickly and accurately if it can be made full use of. The failure alert collected by the dispatch center contains the timing information, thus constitutes the time sequence. In this paper, the concept of time series and Petri net are introduced into the fault analysis of electric power system. An electric power system fault analysis method based on time series Petri net is proposed. First, the concept of time series Petri net and its method are presented. Subsequently, the method is improved and applied to fault diagnosis of electric power system. The time series Petri net model is constructed. The fast correction method is presented, which fully utilizes the time sequence attribute of the circuit breaker action information. The proposed method make use of the timing characteristics of alarm information sequence and still can quickly identify the false alarm in complex situations. Finally, the process of fault analysis is explained.

Because there are two more adjustable parameters and λ, the μ fractional order PIλ Dμ controller is more flexible and effective on controlling the controlled objects than the conventional one. A new strategy of multi-loop fractional order controller, of which the parameters are set by the Particle Swarm Optimization, is presented based on the non-linear, parameters-time-varying, and large time-delay characteristics of the thermal power unit, which is multi-variable with strong coupling.

All ships make good use of the satellite transportation system to communicate external as well as internal data understanding on the sea. At that time, there is diverse kinds of information to communicate one another such as voice, letter, picture and video on the sea to sea, sea to ground. In addition, there are other means to share information like a sign, voice, message, picture and video shared between vessels and ground units. Although the ships utilized FDMA in the initial stage of the satellite procurement, MF/TDMA method is recently applied as means to transmit information. Both FDMA and MF/TDMA, however, are not the best means of data transmission as the number of bandwidth is limited for both methods. Thus, in order to provide a solution for this problem and to see how the amount of transmission increases, a research on applying MF-TDMA + SCPC has been conducted for the Navy’s satellite communication system for the efficiency of the satellite network within the original frequency bandwidth will be maximized through the application of digital transformation methods and Roll OFF Factor as a means of data transmission.

Because that the scraper conveyor chain tension control has characteristics of randomness, nonlinear and time-variation in the coal mine, the paper put forward using sliding mode control technology to make tension control system have better dynamic performances. This method utilizes combined reaching law that combining exponential reaching law and variable rate reaching law to design switching function, then calculates the law of sliding mode control for chain tension control system, in order to constantly make tension move along the prescriptive state trajectory. The results of simulation show that, chain tension control with sliding mode control method has better dynamic characteristics of smaller overshoot, no oscillation and stronger robustness.

In this paper, the design of decimation in time Radix-2 FFT processor is presented, which is integrated in FPGA chip, regarding FPGA as design carrier. New butterfly-shaped operation method is proposed based on the traditional FFT algorithm and the analysis of hardware unit, which can reduce multiplication. And it adopted the Look-up table method. The results of hardware test of FFT processor shows that the processor works well and has high speed, and the design was realized by using FPGA.

Stemming is a very important natural language processing task that to remove all inflectional affixes from a word, and to lemmatize the remaining part of the word. It is very important in most of the Information Retrieval systems. In this paper we have introduced different stemming algorithms that commonly used in English and other English-Like European languages, and also introduced methods used in Chinese word segmentation, finally we have carried out a more detailed discussions about the methods for Uyghur stemming.

A method of strong stability controller design for interval system is proposed in this paper .The nominal value of the controller is designed based on H∞ theory. Combine with Arguon’s theoretical analysis the characteristics of the controller gain to get a strong stable controller.The innovation of this paper lies in separate interval system perturbation to design nominal controller utilize H∞ theory, analyze the characteristic of the gain of interval controller apply Arguon’s theory to improve the stability. At last, a numerical example is given for the design of a strong stability controller applied to an electro hydraulic position servo system.

This paper presents a resonant isolated dc-dc converter for the LED backlight drive of the LCD TV module with a simple resonant half-bridge flyback converter power topology. The power topology structure of the proposed converter is isolated using the half-bridge flyback converter power topology with a transformer. The proposed converter switches complementarily its primary half-bridge switches and achieves high efficiency using the resonant circuit, composed of a resonant inductor and a blocking capacitor. The leakage inductance of the main transformer is used as the resonant inductor, and thus the proposed converter can be simplified. In this paper, the operational principle is analyzed, briefly, and a 100-W-class prototype is implemented based on the analysis. Then, it is shown that the proposed converter has good performance as a driver of the LED backlight drive of the LCD TV module through the experimental results of a 100 W prototype under a wide input voltage and load range.

Effective identification of wood decay and crack defects by using support vector machine (SVM) theory. Extracting wood defect image through the image acquisition system, then processing the defect image by using gray level change, equalization, and median filtering et al. So as to achieve the purpose of improve the image quality and detection accuracy. Segment the target images, and then measures the area, perimeter, and diameter of the wood defects. Three eigenvalues, area and perimeter square ratio, length to diameter ratio and circumference and area ratio, which can be identified the wood defects was obtained. Separating these eigenvalues into training set and testing set. Training Support vector machine by using training set, establish a preliminary model of support vector machine. Using support vector machine model for accuracy test, if the test accuracy is low, repeatedly adjust the parameters of support vector machine for training and testing until reach the test accuracy. Making sure the kernel function and various parameters of support vector machine, constructing the support vector machine, which using for wood defect classification. The experimental results showed that this method has fast calculation speed, high precision, and helps to raise the utilization rate of wood.

With the development of financial derivatives market, stock index futures has been a powerful tool in discovering price and hedging. It’s critical whether stock index futures has significant effects on the volatility of the stock market. Based on the extensive literature review, we firstly estimate the daily volatility of the CSI 300 Index by realized bi-power variation. Then we use multiplicative error model to model the volatility of CSI 300 Index before and after CSI 300 index futures launched respectively. Then, we test whether the introduction of CSI 300 index futures have a significant impact on the volatility in stock market by using statistical methods. The research results show that the introduction of CSI 300 index futures reduces the volatility of CSI300 Stock Index apparently. As the representative of financial derivatives, CSI 300 index futures can effectively reduce the systemic risk of the stock market and it can also promote the maturity of China’s stock markets.

Autonomous driving of mobile robot is important in various working environments. For its autonomous driving, mobile robot utilized ultrasonic sensor to detect obstacles and avoid them. Also, there have been researches on supplementing function of avoiding crash by using control methods based on adoption of intellectual system. This research has designed type-2 fuzzy self-tuning PID controller which can enhance autonomous driving function of mobile robot under fixed obstacle environment. The fuzzy controller has utilized type-2 with multiple values and the fuzzy self-tuning PID controller adjusting gain value of PID controller is applied. 25 rules have been reduced to 9 rules to improve function of hardware. Type-2 fuzzy self-tuning PID controller is used to compare function of traditional PID controller and Type-1 fuzzy self-tuning PID controller. In terms of function of Type-2 fuzzy controller with reduced number of rules, it was confirmed through improvement in function of autonomous driving of mobile robot using MATLAB/Simulink.

The repeatability of system is a fundamental requirement for various iterative learning control methods, and is a necessary condition for the outcome of perfect tracking. This paper theoretically and numerically explains that how the history before the initial time of dynamic systems influences the current state and repeatability of the system. To this end, the convergence analysis of PD-type iterative learning control for initialized system is presented. A practical preconditioning strategy is added to accelerate the convergence speed, and the detailed discussions of initialization function and initialization response are shown as well. The minimum preconditioning time interval is achieved, and some unique properties of initialized system are illustrated to provide novel challenges for robust and adaptive controls. A number of numerical simulations exhibit that a simple preconditioning process can efficiently improve the performance of the initialized iterative learning control.

To improve the accuracy and reduce the response time of traditional gas regulator, a Proportional Integral Derivative (PID) neural network controller of electric gas regulator is proposed by combining conventional digital PID with neural network. And the parallel architecture of the PID neural network is implemented by using Field Programmable Gate Array (FPGA). The neural network is demonstrated in a closed loop system of electric gas regulator and the ideal system output can be obtained by using this improved neural network algorithm. Theoretical analysis and simulation results show that the PID neural network pressure controller based on FPGA can achieve faster response speed and higher control accuracy compared with those based on software, and be obvious to improve the efficiency and security of the electric gas regulator.

Since a telepresence robot is designed to facilitate interpersonal communication between a remote sender and a receiver at distance, the presence of a remote sender as perceived by a receiver is an important aspect of the interaction. In order to determine effective ways to increase the presence, we execute an experiment comparing a telepresence robot without motion cues, a telepresence robot with synchronized motion cues which provides synchronized motion with remote sender’s motion, and a robot with unsynchronized motion cues which provides independent motion and unsynchronized with remote sender’s motion (N=48). In this study, the participants engage in conversations with a remote sender through a telepresence robot. The results show that participants have a greater sense of sender presence when interacting with a telepresence robot with synchronized motion cues than when interacting with a robot with unsynchronized motion cue and a robot without motion cues. On the other hand, participants have a lesser sense of robot presence for a telepresence robot with synchronized movement compared to a robot with unsynchronized motion cues and a robot without motion cues. When interacting with a telepresence robot having either synchronized or unsynchronized motion cues, participants perceive greater sense of sender presence and robot presence than with a robot without any motion cues.

The support process of carrier aircraft is a complex closed-loop system with time delay and parallelism. At present, the related literature is lack of research on parallel closed-loop system. Since System Dynamics is a method that can reveal the dynamic process of complex system. Therefore, this paper proposes a modeling method of parallel closed-loop operation based on System Dynamics. The support process model for carrier aircraft is established in order to analyze the parallel closed-loop system of carrier aircraft. The flow chart and the system structure equations of support process are presented for analysis of the dynamic process and the static performance. The simulation is based on the actual data of Nimitz Aircraft Carrier. The influences of fueling operation, weapons loading operation, other operations and strike task on support capacity are simulated and analyzed. The bottleneck factors affecting support capacity are found through simulation and analysis. A new evaluation method of carrier aircraft support process is proposed. This paper provides a reference to improve the carrier aircraft support capacity and aircraft carrier combat capacity.

The nonsymmetric and dense coefficient matrix of integral equation method results in low computation efficiency and large memory cost in induced magnetic field computation of large scale ships. In order to improve the computation efficiency, a new method called FMMIEM is developed based on fast multipole method and integral equation method. The basic formulas of the FMMIEM were deduced. The numerical implementations of the multipole expansion, multipole to local translation and local expansion were described in detail. The FMMIEM not only has the virtue of the vector integral equation method which needs only meshing source area and is easy to deal with the infinite domain problems, such as the induced magnetic field modeling, but also has the excellent performance of the fast multipole method in conjunction with iterative solver which can accelerate the matrix vector product. The analytical numerical experiment of the sphere magnetized in the uniform applied magnetic field and the magnetostatic field modeling of the main cabin of the simple submarine mockup were designed and the results showed that the FMMIEM is with the high calculation accuracy and reduces costing time obviously. The proposed method is very helpful in engineering.

It is well known that the electro-hydraulic actuator (EHA) system is exposed to the disturbances, uncertainties, and parameter variations which are caused by the changes in operating conditions for instance, total moving mass, supply pressure, servo-valve gain, bulk modulus, leakage coefficient, and friction. These problems pose to a great challenge in modelling and controller development for an EHA system. Degradation of the desired performance can be imposed if an improper control strategy is utilized. This paper discusses the fundamental study on the significant effect that leads to degradation of EHA system performance due to variation in the system parameters. A nonlinear EHA system model is developed and implemented in the simulation studies in open-loop and closed-loop control configuration. The finding shows that the servo-valve gain resulted the most influential parameters to the EHA system performance as compared to the total moving mass and supply pressure parameters. In order to overcome these issues, the utilized controller should be robust enough to overcome the entire operating range that against such disturbances, uncertainties, and parameter variations. Therefore, a nonlinear and the intelligent control approach may be necessary to be designed in order to overcome these difficulties.

The paper proposes a grayscale images watermark authentication system based on SVD. The grayscale image is divided into the pieces of size 16*16. Each small piece is made into DCT transform and extracted low frequencies to generatethe watermark image. Then, the watermark image is made in Arnold scrambling algorithm and embedded in SVD algorithm. The hash algorithm is used to generate authentication code. In the authentication stage, when the image was tampered and attacked, the system can effectively lock the tamper region.

Concern about the poor performance of traditional shipbuilding industry, in China and elsewhere, is coming at a time when new-type offshore equipments are demanding more and becoming increasingly complex under technology innovation. the government encourages shipbuilding enterprises enter offshore equipment manufacturers, especially the emerging offshore oil & gas equipment ones. The paper explores the problems and solutions in aligning between the government and enterprises during the entering process, following the basic principles of evolution game, and constructs the evolution game model of government-enterprise. It focuses on analyzing the factors of selecting strategies by various game bodies, then discusses the payment functions of main bodies under different strategies, finally establishes the corresponding replication dynamic equation to seek evolution stability strategies. The simulation on the dynamic evolution processes indicates the proposed algorithm is effective and feasible.

Flexible manipulators active vibration control has been subject to a large number of research papers due to its high potential for industrial applications. However, this approach generally requires the feedback of state variables that are not always available via direct measurements. The present study proposes a state estimation scheme for a nonlinear one – link flexible manipulator based on the Extended Kalman Filter. First, the flexible manipulator, seen as an Euler-Bernoulli cantilever beam, is modeled using The Hamilton’s principle, the elastic movement is approximated using the assumed modes method and the system non linear equations are introduced and converted into the matrix form. Then, the observability of the system is proven and the Extended Kalman Filter scheme is detailed. This article compares, via the numerical simulation results included, the efficiency of the state estimate, reflected by the estimation error and the time required by the filter to converge, relatively to the assumptions on the available measurements.

The development of an innovative controller for looper and tension control in hot strip finishing mills is traced based on the combination of H∞ and ISMC (integral sliding mode control)approaches. First, an H∞controller is designed to robustly attenuate the unmatched disturbances in the angle and tension loops. Then, ISMC is used to overcome the matched disturbances in the actuators which guarantees the reliability and performances of the overall system. This solution has been considered thanks to it swell-known robustness and simplicity characteristics concerning disturbances and un modeled dynamics. Simulation results show the effectiveness of the proposed controller compared with conventional ones.

Wireless sensor networks are the main technical means to realize variables information network monitoring in agricultural environment. In order to solve the problem of low-cost, low-power field information, reliable real-time transmission, a farmland information online monitoring based on wireless sensor network has been designed. The overall structure of the system contains sensing layer, transport layer and application layer, which uses the ZigBee wireless communication technology to build wireless sensor networks. Monitoring data of different farmland regions are transmitted through the GPRS network to the monitoring center securely and reliably. The use of data monitoring center is aimed at collecting data for processing. TI's ultra-low-power micro-controller MSP430F149 and ZIGBEE module CC2530F256 work as the core hardware in the designing of wireless sensor network node. With Z-Stack as the protocol stack, software is designed based on the nodes to achieve a gateway node and terminal node functions. The results gained from a set of network communication system tests, inter-node transmission quality tests and remote transmission tests show that: based on wireless sensor network, the online monitoring system of field information can automatically complete the data acquisition and transmission and with the aid of GPRS / Internet network, the data can be sent to the data server with high stability, high reliability, punctuality, meeting the basic requirements of on-line monitoring of farmland information.

The latest mobile devices usually use multi-core technologies such as dual-core, quad-core or octa-core for high performance. Further, as the capacity of main memory in the mobile devices is growing, a lot of tasks are capable of running concurrently. With these trends, however, mobile devices run out of battery power faster than before. In recent years, next generation non-volatile memory technology (NVRAM) have developed significantly and considered as low-power main memory architecture. Traditionally, the bandwidth-aware multi-core task scheduling schemes have been studied in order to address the bandwidth saturation problem of shared main memory. In this paper, we propose a multi-core scheduling scheme considering DRAM/NVRAM hybrid main memory. The goal of the proposed scheme is to reduce the execution time of tasks by avoiding the memory bandwidth saturation as well as to improve the response time of interactive tasks. We have showed through trace-driven simulation that the proposed scheme outperforms the legacy scheduling schemes.