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Détails du magazine
Format
Magazine
eISSN
1178-5608
Première publication
01 Jan 2008
Période de publication
1 fois par an
Langues
Anglais

Chercher

Volume 7 (2014): Edition 4 (January 2014)

Détails du magazine
Format
Magazine
eISSN
1178-5608
Première publication
01 Jan 2008
Période de publication
1 fois par an
Langues
Anglais

Chercher

32 Articles
Accès libre

Design And Experimental Verification Of State Predictive Lqg Controllers For Networked Control Systems

Publié en ligne: 01 Sep 2014
Pages: 1201 - 1220

Résumé

Abstract

This paper considers a design problem of controllers for wire-less vehicles in the developed networked control system. The developed system consists of a wire-less vehicle and some computers which configure a computer network. The vehicle is controlled over the computer network. One of the computers is a router which has an active queue management mechanism to keep the queue size constant and to control congestion in the computer network. The dynamics of the vehicle over the computer network can be described as linear systems with an input time-delay. State predictive LQG controllers are designed to achieve the stability and better performances of the vehicle over the computer network. The efficacy of the designed controller is demonstrated in a numerical example and an experiment using the developed networked control system.

Mots clés

  • Networked control systems
  • linear time-delay systems
  • input-time delays
  • state predictive control
Accès libre

Design of Digital Image Encryption Algorithm Based On Mixed Chaotic Sequences

Publié en ligne: 01 Dec 2014
Pages: 1453 - 1469

Résumé

Abstract

Digital image scrambling is to transform a digital image, to make it unrecognizable and become another chaos images without obvious meaning. If the operator knows the algorithms, he can reconstruct the original image from the chaos image by using the certain algorithms. Image scrambling encryption technology that based on Chaos Theory encrypts the image data stream through using the chaotic signal. It has the advantage like high security, encryption speed, large key space, and good scrambling effect. This paper studies the “extraordinary Key” and “to be trivial key” that are in the chaotic sequences that is caused by Logistic map, thus presents a image chaotic encryption algorithm that is based on hybrid chaotic sequence. Firstly, the algorithm generate hybrid chaotic sequence through the key; then through generates the corresponding offset matrix and permutation matrix the discrete mapping; finally, do the implementation of wavelet transform to the image, do the digital image scrambling encryption in the transform domain. In order to measure the degree of scrambling, we propose a “scrambling degree” concept. Experiments confirmed that the encryption algorithm has good scrambling in nature, and achieved good encryption effect. It confirmed the degree of scrambling encryption can effectively reflect the effect of scrambling encryption of the algorithm.

Mots clés

  • chaotic sequence
  • images
  • scrambling
Accès libre

A Scene Recognition Algorithm Based On Multi-Instance Learning

Publié en ligne: 01 Dec 2014
Pages: 1470 - 1492

Résumé

Abstract

In Bag of Words image presentation model, visual words are generated by unsupervised clustering, which leaves out the spatial relations between words and results in such shorting comings as limited semantic description and weak discrimination. To solve this problem, we propose to substitute visual words by visual phrases in this article. Visual phrases built according to spatial relations between words are semantic distrainable, and they can improve the accuracy of Bag of Words model. Considering the traditional classification method based on Bag of Words model is vulnerable to the background, block and scalar variance of an image, we propose in this article a multiple visual words learning method for image classification, which is based on the concept of visual phrases combined with Multiple Instance Learning. The final classification model is able to show the spatial features of image classes. Experiments performed on standard image testing sets, Caltech 101 and Scene 15, show the satisfying performance of this algorithm.

Mots clés

  • Image Classification
  • Multiple Kernel Learning
  • Bag of Visual Words
  • Spatial Pyramid Matching
Accès libre

Face Alignment Based On Semi-Active Appearance Mode

Publié en ligne: 01 Dec 2014
Pages: 1493 - 1515

Résumé

Abstract

In the information era, the technology of biological character recognition has attracted more and more attentions. In this paper, by investigating theories of active appearance model and inverse compositional image alignment algorithm, we mainly proposed a semi-active appearance model for face alignment based on improving the classical models in the aspects of computation complexity, easily suffering from light, angle and expression, and so on. Firstly, the model of active appearance and the algorithm of alignment are investigated. For the inefficiency of classic gradient descent method in the matching process, the inverse compositional image alignment algorithm is proposed. Then, through combining the active appearance model and Grey Level Co-occurrence Matrix, a novel semiactive appearance model is proposed, which has a simple calculation and higher accuracy of face alignment. Finally, experiments were designed to demonstrate the effectiveness of the proposed algorithms.

Mots clés

  • face alignment
  • active appearance model
  • inverse compositional alignment
  • grey level cooccurrence matrix
Accès libre

Research and Restoration Technology of Video Motion Target Detection Based on Kernel Method

Publié en ligne: 01 Dec 2014
Pages: 516 - 1534

Résumé

Abstract

In recent years, due to the video surveillance applications more and more widely, people are not satisfied with the goal of monitoring, and the video monitoring technology of intelligent video moving object detection and tracking technology has received extensive attention. The research work in this paper is in the field, the moving target detection spatiotemporal correlation and difference contour tracking algorithm based on a fixed background. The algorithm in the background under the condition of fixed to pay a smaller time complexity, the target detection and tracking has a good effect, so it has higher application value. In this paper, the prospect of caused motion detection of occlusion background foreground correlation problem, put forward the video moving object detection method based on kernel independent component analysis, canonical correlation to minimize the component in the high dimensional feature space in order to separate the foreground nuclear background. Independent component analysis assumes that the foreground and background independent, avoid the correlation problem. The two objective functions based on Kernel Independent Component Analysis: analysis of kernel independent component analysis based on kernel canonical component (KCCA) and kernel independent component analysis (KGV) based on the generalized variance. KCCA is the application of canonical correlation analysis in the kernel method, discuss is the first canonical correlation separation component of high dimensional map, and KGV are typical correlation between the components in the high dimensional space of the whole spectrum. Both KCCA and KGV improved the accuracy of motion detection.

Mots clés

  • Moving object
  • kernel method
  • active
  • pattern recognition
  • image features
Accès libre

A Self-Adaptive Data Balance Protocol For Distributed Radio Frequency Identification Sensor Network

Publié en ligne: 01 Dec 2014
Pages: 1535 - 1554

Résumé

Abstract

In this paper, we share our recent work related to Radio Frequency Identification (RFID) sensor network with readers. The work mainly focus on the protocol for network system to perform the task of autonomous decentralized data distribution with consideration of economic and low-power RFID-sensor module scheme. We analyzed data pitfall in distributed RFID-sensor network, revealing the reason lies in the phenomenon. A distributed solution to tackle the problem has been designed in a simple way. The test results show that the system with proposed approach provides an efficient and more balanced in data distribution which proves the protocol is feasible for the application scenario.

Mots clés

  • RFID Sensor network
  • equal probability scheduling
  • stochastic switching
  • Galton effect
Accès libre

Design and Construction of Light Weight Portable Nmr Halbach Magnet

Publié en ligne: 01 Dec 2014
Pages: 1555 - 1578

Résumé

Abstract

A light weight, simple design NMR apparatus consists of 24 identical magnets arranged in Halbach array was designed and built. The homogeneity of the magnetic field B0 can be improved by dividing a long magnets into several rings. The size of the useful volume depends on both the gap between each ring and some others shim magnets. Our aim is to enhance the sensitive volume and to maintain the highest magnetic static field (B0). This apparatus generates a B0 field strength of about 0.1 T. This work focuses on the magneto-static simulation of NdFeB magnets arrangement and on the comparison with the measurement of the magnetic field strength and homogeneity in three dimensions (3D). The homogeneity of the magnetic field B0 is optimized with the help of CAD and mathematical software. Our results were also validated with a Finite Element Method (FEM). The simulation results of the strength and of the homogeneity of B0 field were compared to those obtained with a digital gaussmeter. The homogeneity in the magnet longitudinal axis and the field B0 strength are similar. However, the homogeneity in transverse plane differs from simulation and measurement because of the quality of the magnets. In order to improve the homogeneity, we propose a new shim method.

Mots clés

  • Nuclear Magnetic Resonance (NMR)
  • Low field
  • Portable Permanent Magnet
  • Halbach
  • Shim magnets
  • Homogeneity
  • Simulation
  • Finite Element Method (FEM)
Accès libre

Simulation of the Leakage Effect In Capacitive Sensing

Publié en ligne: 01 Dec 2014
Pages: 1579 - 1594

Résumé

Abstract

In the measurement of mutual capacitance between electrodes both the coupling and the leakage effect contribute to the measurement result whereas the leakage mode is dominant in the selfcapacitance mode. While the coupling effect is mainly defined by the geometry and material distribution close to the electrodes, the root cause or modulation of the leakage effect may be far away from the electrode. In this paper we demonstrate that the leakage mode concept allows for simulation of 3D problems in 2D. This is useful in applications such as Electrical Capacitance Tomography or object classification as it allows simplifying the computational complexity while providing additional information compared to the classical 2D approach.

Mots clés

  • leakage effect
  • capacitive sensing
  • open environment
  • ECT
  • reconstruction
Accès libre

Measurement And Analysis Of High Temperature Using Distributed Fiber Optic Sensor

Publié en ligne: 01 Dec 2014
Pages: 1595 - 1612

Résumé

Abstract

In this paper the working principle and application status of distributed optical fiber temperature sensor, amplified spontaneous Raman scattering phenomenon and its time-domain characteristics are analyzed. A new measuring principle based on amplified spontaneous Raman scattering light pulse signal temperature effect is presented, and is applied to distributed optical fiber sensor systems. Noise inevitably exists in data collected by distributed optical fiber temperature sensing systems. According to the needs of high-temperature oil well testing, distributed high temperature single-mode fiber sensors and detection equipment are designed, and gives two-dimensional data of oil well temperature testing. Because of the weak Raman backwards scattered signal and serious noise disturbance, multi-resolution wavelet analysis and reconstruction method are adopted for the denoising of testing signal.

Mots clés

  • Fiber optic
  • Sensor
  • Digital signal processing
  • Temperature control
Accès libre

Multi-Agv Scheduling Optimization Based on Neuro-Endocrine Coordination Mechanism

Publié en ligne: 01 Dec 2014
Pages: 1613 - 1630

Résumé

Abstract

To solve the problems of task scheduling and coordination control presented by a multi-AGV system, the mixed regional control model for the production task has been advanced. The architecture of multi-AGV task assignment and scheduling mechanism has been proposed by combining the mixed regional control model for the production task and the neuro-endocrine coordination mechanism. Hormones for manufacturing cell are secreted by the machine tool according to the information in the production task, and the task can be allocated to the most suitable machine according to the hormone concentrations of the manufacturing cell. The AGV’s hormones are secreted according to the AGV’s operation state. The AGV with the largest hormone concentration will be chosen to execute the transportation task, thus shortening the overall run time of the system. A series of scheduling simulation experiments are performed for some specific examples to demonstrate the feasibility and efficacy of the proposed approach. The results show that tasks can be allocated according to the current status of a machine tool and tasks can be scheduled according to the current state of the AGV system to maximize the efficiency of the AGVs as well as that of the overall system.

Mots clés

  • multi-AGV
  • scheduling strategy
  • coordination control
  • neuro-endocrine coordination mechanism
  • scheduling simulation
Accès libre

Orientation Of A Triaxial Accelerometer Using A Homogeneous Transformation Matrix And Kalman Filters

Publié en ligne: 01 Dec 2014
Pages: 1631 - 1646

Résumé

Abstract

The evolution in the development of manufacturing techniques of electronic components, including accelerometers, has allowed access to a new field of research and applications in consumer electronics. The aim of this work is to present a method for aligning triaxial accelerometers, finding the parameters of the rotation, the translation and the scale of the homogeneous transformation matrix. In principle, it is necessary to acquire six points to build the frame of reference of the accelerometer and ensure the consistency of the measurements, in order to check the angle between the axis and the magnitude. Subsequently, using spatial geometry, the intersection of the system of reference is estimated, to determine the extent of translation in the homogeneous transformation matrix. In a further step, the rotation values of the matrix are generated by taking the orientation of the z-axis into account and, finally, the resulting factor is scaled to normalize the magnitude value of gravity. Using the transformation matrix, it is possible to align the original reference system of the accelerometer to another coordinate system. The satisfactory results of this experiment show the need of implementing the here described method to enable the use of variable tilt measurements.

Mots clés

  • Accelerometer
  • alignment
  • tilt
  • translation
  • triaxial
  • rotation
Accès libre

Design Of A Four-Wing Heterogeneous Fractional-Order Chaotic System And Its Circuit Simulation

Publié en ligne: 01 Dec 2014
Pages: 1647 - 1662

Résumé

Abstract

Integer orders differential system is a special case of fractional-order differential system. Integer orders chaotic system that we usually study is ideally approximate to realistic chaotic system. Fractional-order chaotic system has broader and changeable values of order and more complex dynamical behavior than integer order chaotic system. Thus, fractional-order differential equation can describe the nonlinear characteristics of actual chaotic system more exactly, which has more prominent research meanings and application value. This paper designs a new four-wing four-dimensional heterogeneous fractional-order chaotic system, when the values of fractional-order qi(i =1,2,3,4) are not identical( q1 = q2 = 0.9, q3 = q4 =0.8, in step size of 0.1), the attractors of this chaotic system will all show four-wing shapes in any direction. After analysis this chaotic system’s stability and existence, this paper also introduces a nonlinear state feedback controller, and adopts the chain shape circuit to conduct experiment simulation through Multisim software 10.0. The results of circuit simulation and Matlab numerical operation have the same chaotic attractor phase diagram. This demonstrates the effectiveness of this four-wing four-dimensional heterogeneous fractional-order chaotic system’s design and the feasibility of the feedback controller in the circuit; meanwhile, it provides referable bases for the application in actual circuits.

Mots clés

  • Fractional-order differential system
  • chaotic system
  • heterogeneous fractional-order
  • circuit simulation
  • feedback control
Accès libre

Connectivity-Aware Topology Control With Cyclic-Like Structures In Wireless Sensor Networks

Publié en ligne: 01 Dec 2014
Pages: 1663 - 1682

Résumé

Abstract

Connectivity offers the foundation for achieving required quality of service in all WSN applications. By the concept of cyclic-like topologies proposed and their property proved, we find a new searching method based on cyclic paths on nodes and their combination, which cuts down the cost of ensuring bi-connectivity in this problem. On the basis of graph and probability theory, our centralized connectivity-aware algorithm with cyclic-like topologies and computation of link reachability is proposed. Results of the experiments show that, our topology control algorithm could be more satisfactory than that of another two algorithms in different scales of networks.

Mots clés

  • Wireless Sensor Network
  • connectivity
  • topology control
  • fault-tolerant
  • cyclic-like topologies
  • biconnected
Accès libre

Applications Of Compressive Sensing Over Wireless Fading Channels

Publié en ligne: 01 Dec 2014
Pages: 1683 - 1700

Résumé

Abstract

Wireless fading channels exist mixed noise, the most common noises are gaussian noise and impulse noise, to ensure the quality of the received signal, removing the noise in the channel is very important and necessary. WSDN (wavelet soft-threshold de-noising) can suppress low-intensity gaussian noise well; unfortunately, the denoising effect in removing impulse noise using WSDN is not obvious, especially when noise intensity is relatively high. BPDN (Basis Pursuit Denoising) which is a reconstruction algorithm of compressive sensing can control high-intensity gaussian noise in the channels well preceding WSDN, but also the effect of BPDN denoising the common impulse noise is not obvious, to denoise impulse noise, we adopt IBPDN (Improved Basis Pursuit Denoising) that changes L2 form to noise to L1 form, which was proposed in 2006 by Guosheng Bing. The experimental data show that IBPDN has good anti-noise ability to both gaussian noise and impulse noise; furthermore, more satisfactory results are obtained using IBPDN to mixed noise than those with BPDN.

Mots clés

  • IBPDN
  • BPDN
  • WSDN
  • Wireless fading channels
  • denoising
Accès libre

Research Of Multi Sensor Intelligent System Signal Fusion And Reconstruction

Publié en ligne: 01 Dec 2014
Pages: 1701 - 1716

Résumé

Abstract

This paper studies some key technology of multifunctional sensor signal reconstruction. The multifunctional sensor signal reconstruction problem, presented a multifunctional sensor signal reconstruction method based on B spline and the extended Caiman filter. The method of inverse model of the process was studied, gives a method to estimate signal reconstruction accuracy and computation. Genetic algorithm is proposed to balance the multifunctional sensor signal reconstruction accuracy and computation based on. In order to further reduce the sampling effort of large quantities of multifunctional sensor signal reconstruction, is proposed based on the reduction method clustering multifunctional sensor sample selection method, to select the reasonable distribution, suitable for inverse training data model. A new direction to study the theory of multi sensor information fusion is to design and analysis more efficient processing of multi sensor intelligent system is proposed and developed. With the continuous improvement of the intelligent system requirements, research on information fusion of multi-sensor system is affected by the people more and more attention.

Mots clés

  • Multi-sensor
  • signal reconstruction
  • complex
  • sample detection
Accès libre

Research On Wtg Power Performance Monitoring Methods Of Regional Wind Power Group

Publié en ligne: 01 Dec 2014
Pages: 1717 - 1735

Résumé

Abstract

With growth of the wind power scale and the increasing of urgent requirement on operating life extension of units followed with which, how to monitor regional wind power group automatically and find recession performance of WTG power so as to take measures timely to restore the health condition and reduce power losses has become an important problem to be solved by wind farm operators. Horizontal and longitudinal performance comparison methods of the power characteristics for the same area and model units are proposed in this paper. Different real-time monitoring and analysis methods are used. The core technology of which is using wind speed partitioning technology and Wavelet analysis. Longitudinal power performance monitoring comparison method of single-unit is used as a further preferred aspect scheme of information fusion. Research results are verified by Matlab simulation platform. The study results integrated with the developed centralized monitoring system software, can improve the efficiency of wind farm operation and monitoring in large degree, further ensure the profitability production for wind farm plants.

Mots clés

  • Regional wind power group
  • Bin method
  • Wavelet analysis
  • Horizontal and longitudinal comparison
  • Power performance monitor
Accès libre

Zigbee Transmission Power Dynamic Adjustment System Based On Fuzzy Control

Publié en ligne: 01 Dec 2014
Pages: 1736 - 1752

Résumé

Abstract

We designed a fuzzy controller for ZigBee equipment’s transmission power adaptive adjustment. The controller is based on RSSI (Received Signal Strength Indicator). It can make a dynamic adjustment on the transmitted power according to the fuzzy control rules. The fuzzy control is suitable to solve the problem which is difficult to deal with in building system mathematical model. What’s more, the fuzzy control system has perfect performance in response speed and antijamming capability. It’s convenient to embed in devices. In this paper we use Ti Company’s CC2530 chip as an experiment object. By using the fuzzy controller we keep the transmission power to the minimum. By this way, the energy consumption can be reduced on the premise of ensuring normal communication. The fuzzy controller system has a good steady-state and dynamic performance, and contributes to the ZigBee system’s stability and low power consumption performance.

Mots clés

  • fuzzy control
  • ZigBee
  • RSS
  • CC2530
  • low power consumption
Accès libre

Research On Underwater Target Signal Detection And Recognition Processing Algorithm

Publié en ligne: 01 Dec 2014
Pages: 1753 - 1772

Résumé

Abstract

Practical application of underwater target echo signal usually get disturbed a Gaussian noise and non-Gaussian noise, in view of the signal recognition problem, this paper proposes a double spectrum analysis based on wavelet transform domain method of weak signal and D-S data fusion algorithm. Through the study of double spectrum of the wavelet transform domain analysis to the signal processing algorithm, the characteristics of the target signal and noise source signal, a processing method of underwater target signal de-noising was presented. For multiple underwater target recognition, the model of underwater target multi-sensor signal recognition was studied. On the basis of analyzing the principle of D-S method and the fusion of multiple signal recognition, the concrete measures of D-S data fusion reasoning was researched and analyzed. By using the combination of simulation calculation and experiment measures, the results show the signal processing method is correct.

Mots clés

  • wavelet transforms
  • the double spectrum analysis
  • signal recognition
  • data fusion
Accès libre

Numerical Analysis of Sliding Friction Coefficient and the Normal Pressure Between the Cable Wire

Publié en ligne: 01 Dec 2014
Pages: 1773 - 1788

Résumé

Abstract

In this paper, the wire pressing device is designed, the range of true positive pressure, curves of steel friction coefficient changes with positive pressure. Describe the change trend of friction coefficient is: with the increasing pressure, friction coefficient of cable parallel wire decreased significantly, but when the pressure increases to a certain value, the friction coefficient decline is slowing down, and finally tends to a certain value. The curves of friction coefficient changes with positive pressure, provides a method and basis for the practical engineering of steel wire in the ultimate friction shear stress accurately, set up and stay cable as layered slipping model provides important parameters of bending stress analysis. From the numerical simulation method analyzes the positive pressure parallel wire between the start. This paper first parallel wire contact problem of two cables are analyzed with the classical theoretical solution and the FEM software ANSYS, to verify the feasibility, using ANSYS to solve the contact problem of accuracy and precision. On this basis, the strand steel beam of contact analysis, the preliminary inquiry arching effect on cable parallel wire.

Mots clés

  • Stay cable
  • positive pressure arch effect
  • mechanism
  • friction coefficient
  • ANSYS
  • contact analysis
Accès libre

The Smart Home System Based on the Iap15F2K61S2 and Gsm

Publié en ligne: 01 Dec 2014
Pages: 1789 - 1806

Résumé

Abstract

At home, there are all kinds of electrical devices. Also the gas may leak to fire. Once the danger happens, it will result in the huge losses. The smart home system is necessary for the safety. The system integrated the sensors to monitor the appliances whether they work normally. Once the exceptions have been tested, the owner can get the text massage immediately with the help of GSM. This system has a light cube. It has 512 lights. After test, this system works to monitor the home appliances very well at the low cost.

Mots clés

  • IAP15F2K61S2
  • GSM
  • the smart home system
Accès libre

Face Recognition Based On Improved Support Vector Clustering

Publié en ligne: 01 Dec 2014
Pages: 1807 - 1829

Résumé

Abstract

Traditional methods for face recognition do not scale well with the number of training sample, which limits the wide applications of related techniques. We propose an improved Support Vector Clustering algorithm to handle the large-scale biometric feature data effectively. We prove theoretically that the proposed algorithm converges to the optimum within any given precision quickly. Compared to related state-of-the-art Support Vector Clustering algorithms, it has the competitive performances on both training time and accuracy. Besides, we use the proposed algorithm to handle classification problem, and face recognition, as well. Experiments on synthetic and real-world data sets demonstrate the validity of the proposed algorithm.

Mots clés

  • Face recognition
  • biometric feature
  • Support Vector Clustering
  • kernel methods
  • classification
  • large-scale data
Accès libre

Centralized Discrete State Space Model Predictive Control And Decentralized Pi-D Controller Of An Aerothermic Process

Publié en ligne: 01 Dec 2014
Pages: 1830 - 1849

Résumé

Abstract

The aerothermic process is a pilot scale heating and ventilation system equipped with a heater grid and a centrifugal blower. The interaction between its main variables is considered as challenging for mono-variable controllers. A change in the ventilator speed affects the temperature behavior which represents a factor that must be managed for energy saving and the human welfare. This paper presents an experimental comparison between a Centralized Discrete State Space Model Predictive Control (CDSSMPC) and a Decentralized PI-D (DPI-D) controller. These both techniques are designed by using respectively the Laguerres functions and the static decoupler approach. To demonstrate the effectiveness of the two methods, an implementation on an aerothermic process is performed. This pilot scale is fully connected through the Humusoft MF624 data acquisition system for real time control. The results show satisfactory performance in closed-loop of the DPI-D controller compared to the CDSSMPC and the conventional PID ones.

Mots clés

  • Centralized discrete state space model predictive control
  • Laguerre functions
  • Static decoupler
  • Decentralized PI-D controller
  • Multivariable systems
  • Aerothermic process
Accès libre

A Framework For “Energy-Saving Strategies”: Utilization of A cue Offering Interface

Publié en ligne: 01 Dec 2014
Pages: 1850 - 1869

Résumé

Abstract

Mass consumption of energy is a big problem. Energy-saving activities which are a solution to this problem have been attracting a lot of attention. Nevertheless, in order to engage in thorough energy-saving activities, consumers need support; on the other hand, even with support, the effects seem to be only temporary. In this paper, to obtain a long-term effect, we focus on developing a method to raise consumers’ awareness about energy-saving behavior. To this end, we designed an interface which offers consumers the cue to think about energy-saving activities and conducted a 2week-experiment using the interface with 10 participants. The results suggest two things. First, offering cues increases the number of the energy-saving activities. Second, the more times they perform an activity, the less likely it is that they will change their way of thinking about the activity as time passes. We discuss a more effective method of helping consumers create energy-saving strategies.

Mots clés

  • energy-saving activity
  • human interface
  • cue offering
  • sound
  • eco-feedback
Accès libre

Film Thickness Measurement Of Mechanical Seal Based On Cascaded Artificial Neural Network Recognition Model

Publié en ligne: 01 Dec 2014
Pages: 1870 - 1889

Résumé

Abstract

Mechanical seal end faces are separated by a thin fluid film. The thickness of this film must be optimized so as to preventing the serious friction of two end faces and minimizing the fluid leakage. The micro scope condition monitoring of end face is of importance to ensure mechanical seals run normally. A method for measuring the film thickness of end faces and detecting the friction of end faces of mechanical seal has been presented in this paper. Eddy current sensors embedded in the stationary ring of mechanical seals are used to directly measure the thickness of the liquid-lubricated film. The Eddy current signal is decomposed by empirical mode decomposition into a series of intrinsic mode function. The information reflecting the film thickness is obtained by eliminating the false intrinsic mode function components. Acoustic emission sensor placed on the lateral of stationary ring is used to detect the friction of end faces. In order to decrease the acoustic emission signal’s noise, wavelet packet and kernel principal component analysis are used to extract the data features. Then cascaded decision is presented to improve the recognition rate of artificial neural network, by which the film thickness can be estimated accurately. With a set of tests, the results demonstrate that the method is effective. It can be widely used to take measurement of the film thickness in industrial field.

Mots clés

  • Mechanical Seal
  • Film Thickness
  • Eddy Current
  • Acoustic Emission
  • Empirical Mode Decomposition
  • Artificial Neural Network
Accès libre

Coverage Holes Recovery Algorithm Based On Nodes Balance Distance Of Underwater Wireless Sensor Network

Publié en ligne: 01 Dec 2014
Pages: 1890 - 1907

Résumé

Abstract

Underwater wireless sensor network nodes deployment optimization problem is studied and underwater wireless sensor nodes deployment determines its capability and lifetime. Underwater wireless sensor network if no wireless sensor node is available in the area due to used up energy or any other reasons, the area which is not detected by any wireless sensor node forms coverage holes. The coverage holes recovery algorithm aiming at the coverage holes in wireless sensor network is designed in this article. The nodes movement is divided into several processes, in each movement process according to the balance distance and location relations move nodes to separate the aggregate nodes and achieve the maximum coverage of the monitoring area. Because of gradually increasing the balance distance between nodes, in each movement process the nodes moving distance is small and reduce the sum of the nodes movement distance. The simulation and experimental results show that this recovery algorithm achieves the goal of the nodes reasonable distribution with improving the network coverage and reducing the nodes movement distance thus extends the lifetime of the network in the initial deployment phase and coverage holes recovery phase.

Mots clés

  • Coverage Holes Recovery
  • Nodes Balance Distance
  • Wireless Sensor Network
Accès libre

Sound-Separation System using Spherical Microphone Array with Three-Dimensional Directivity—KIKIWAKE 3D: Language Game for Children

Publié en ligne: 01 Dec 2014
Pages: 1908 - 1921

Résumé

Abstract

Mixed sounds can be separated from multiple sound sources using microphone array sensor and signal processing. We believe that promotion of interest in this technique can lead to significant future development in science and technology. To investigate this technique, we designed a language game for children called “KIKIWAKE 3D” that uses a sound-source-separation system to arouse children’s interest in this technology. However, the microphone array sensor in a previous research had a limited scope in separating sounds. We developed a spherical microphone array sensor with three-dimensional directivity designed for this game. In this paper, we report the evaluation of this microphone array sensor in adapting to this game by separating the sound level and using questionnaires.

Mots clés

  • Supporting learning system
  • signal processing
  • frequency-band selection
  • implementation
  • and evaluation
Accès libre

Improving The Localization Of Electric Wheelchair By Using Particle Filter

Publié en ligne: 01 Dec 2014
Pages: 1922 - 1942

Résumé

Abstract

The electric wheelchair for handicapped is used to improve the displacement of disabled persons. An automatic navigation system is needed to ensure greater autonomy and security for the disabled person. Automatic control system is added to a manual control for autonomous displacement. Initial system composed of two DC motors installed at the rear of used electric wheelchair, power module for the motors control and joystick to select speed and moving direction. We include an automatic control system composed by two electronic cards, based on microcontrollers CB405 and PIC16F877 for the signal acquisition from the encoders and distance measurements from ultrasonic sensors (SRF08 and SRF04). The ultrasonic sensors used to improve the localization when we use an automatic control system. Several techniques exist for sensors fusion solves the problems of mobile robots localization. Among these methods, we can quote the particle filter that use data from the encoders and measures from the ultrasonic sensors.

Mots clés

  • electric wheelchair
  • encoder
  • ultrasonic sensors
  • particle filter
  • power module
  • microcontroller
  • CB405
  • PIC16F877
Accès libre

Adaptive Mobile Anchor Localization Algorithm Based On Ant Colony Optimization In Wireless Sensor Networks

Publié en ligne: 01 Dec 2014
Pages: 1943 - 1961

Résumé

Abstract

In wireless sensor networks (WSNs), node’s locations play a critical role in many applications. Having a GPS receiver on every sensor node is costly. In this paper, we propose an adaptive mobile anchor localization algorithm based on ant colony optimization, firstly, some virtual anchor nodes are distributed in the area, second, ant colony was used which has the maximum of transition probabilities to obtain the optimal path, last, the centroid-weighted localization algorithm was proposed to locate the position of unknown nodes. Simulation results show that the localization accuracy of the proposed algorithm is better than the traditional centroid algorithm, the more number of anchor nodes, namely, the density is bigger, the position errors is smaller. Under the same anchor nodes, the more number of unknown nodes, the position errors is smaller and the overall trend is downward.

Mots clés

  • Wireless sensor networks
  • mobile anchor
  • ant colony optimization
  • localization algorithm
  • centroid-weighted
Accès libre

Security Method For Combination Steganography Algorithms On Transform Domain For Jpeg Images

Publié en ligne: 03 Dec 2014
Pages: 1962 - 1979

Résumé

Abstract

Steganography is the act of hiding a message inside another message in such a way that can only be detected by its intended recipient. In any communication, security is the most important issue in the world today. It created a lot of data security and steganography algorithms in the past decade, and that worked motivation for our research. In this paper, Security Method for Combination Steganography Algorithms on Transform domain for JPEG images, we have designed a system that will allow the average user to securely transfer secret messages (picture) securely by hiding them in JPEG image file using local characteristics within the image. This paper is a combination of two steganography algorithms, which provide a strong backbone for its security. The proposed system hides the image unrevealed manner through the use of steganography algorithms to protect each other, where was used F4 algorithm as a wall to protect outguess01 algorithm. We combine between steganography algorithms (outguess 0.1 algorithm and F4 algorithm) to make use of it to provide more than level of protection for the secret message (image). When save the secret message (image) within an image by using outguess01 algorithm, Which produces outguess-image, then hide outguess-image within another image by using F4 algorithm, Which produces F4-image(stego image). Adopt the principle of camouflage and deception to hide image gives another level of safety for secret Image. Good selection of size and type images used in the process of concealment that contributed to the success of the process of embedded and retrieval of hidden images. Results proved after calculating the capacity and PSNR for images that a good and acceptable steganography scheme. The model presented here is based on JPEG images.

Mots clés

  • Transform domain technique
  • OutGuess0.1 algorithm
  • F4 algorithm
  • peak-signal-to-noise ratio (PSNR)
Accès libre

The Effects Of Lumber Seasonal Growth Rings On Microwave Measurements

Publié en ligne: 01 Dec 2014
Pages: 1980 - 1996

Résumé

Abstract

In order to determine more accurate indicators of wood structure obtained by microwave sensing and improve our understanding of plane wave propagation through this complex material, we have undertaken a permittivity survey and experimentally investigated scattering of a plane wave, measuring its transmission over two non-parallel surfaces of a rectangular lumber sample. This novel non-destructive testing technique offers results which may significantly contribute in a more accurate propagation modeling and industrial wood quality testing.

Mots clés

  • microwave
  • non-destructive testing
  • free-space transmission measurement
  • wood
Accès libre

Sharing Research Experiences Of Wsn Based Smart Home

Publié en ligne: 01 Dec 2014
Pages: 1997 - 2013

Résumé

Abstract

We are pursuing our research on ZigBee based WSNs for more than 8 years; a lot of realization stories are conveyed in literature on the development of wireless measurement of sensors data using ZigBee (XBee RF module). Many projects are fruitfully completed for applications such as smart home for elder care, environmental monitoring, big building monitoring and so on. Still a lot of design issues are there while the systems are designed using ZigBees. In this research paper the working experiences which may support other researchers to achieve success without wasting resources are reported. Moreover, presented research analyses of some unusual observations made in a proto-typed smart home monitoring system have been discussed. Packet delivery ratio (PDR) and latency are among a few reliability issues that have been analysed and addressed in this article to make the system more robust.

Mots clés

  • Smart sensors
  • wireless sensor network
  • wireless sensors
  • measurement
  • instrumentation
  • XBee and IEEE 802
Accès libre

Optimal Techniques For Sensing Error Minimization With Improved Energy Detection In Cognitive Radios

Publié en ligne: 01 Dec 2014
Pages: 2014 - 2034

Résumé

Abstract

Spectrum sensing, the problem of detecting the presence of licensed user in the channel is considered in this paper. Energy detection is best suited for the spectrum sensing when prior knowledge about the primary users is unavailable. Existing works report improved versions of energy detection which primarily focuses on maximizing the detection performance. Sensing error minimization is an important aspect of spectrum sensing that needs attention. This paper focuses on the sensing error minimization of the improved energy detection algorithm in which the decision statistic is computed using an arbitrary positive index instead of squaring operation. First, an optimum decision threshold satisfying Minimum Error Bound (MEB) is derived. Next, an optimum value of the arbitrary positive index with minimum number of samples satisfying a Target Error Bound (TEB) is derived. A thorough numerical analysis and simulations are performed and the results confirm the accuracy of the analysis.

Mots clés

  • Spectrum sensing
  • Cognitive radio
  • Energy detection
  • Threshold optimization
  • Sensing error
32 Articles
Accès libre

Design And Experimental Verification Of State Predictive Lqg Controllers For Networked Control Systems

Publié en ligne: 01 Sep 2014
Pages: 1201 - 1220

Résumé

Abstract

This paper considers a design problem of controllers for wire-less vehicles in the developed networked control system. The developed system consists of a wire-less vehicle and some computers which configure a computer network. The vehicle is controlled over the computer network. One of the computers is a router which has an active queue management mechanism to keep the queue size constant and to control congestion in the computer network. The dynamics of the vehicle over the computer network can be described as linear systems with an input time-delay. State predictive LQG controllers are designed to achieve the stability and better performances of the vehicle over the computer network. The efficacy of the designed controller is demonstrated in a numerical example and an experiment using the developed networked control system.

Mots clés

  • Networked control systems
  • linear time-delay systems
  • input-time delays
  • state predictive control
Accès libre

Design of Digital Image Encryption Algorithm Based On Mixed Chaotic Sequences

Publié en ligne: 01 Dec 2014
Pages: 1453 - 1469

Résumé

Abstract

Digital image scrambling is to transform a digital image, to make it unrecognizable and become another chaos images without obvious meaning. If the operator knows the algorithms, he can reconstruct the original image from the chaos image by using the certain algorithms. Image scrambling encryption technology that based on Chaos Theory encrypts the image data stream through using the chaotic signal. It has the advantage like high security, encryption speed, large key space, and good scrambling effect. This paper studies the “extraordinary Key” and “to be trivial key” that are in the chaotic sequences that is caused by Logistic map, thus presents a image chaotic encryption algorithm that is based on hybrid chaotic sequence. Firstly, the algorithm generate hybrid chaotic sequence through the key; then through generates the corresponding offset matrix and permutation matrix the discrete mapping; finally, do the implementation of wavelet transform to the image, do the digital image scrambling encryption in the transform domain. In order to measure the degree of scrambling, we propose a “scrambling degree” concept. Experiments confirmed that the encryption algorithm has good scrambling in nature, and achieved good encryption effect. It confirmed the degree of scrambling encryption can effectively reflect the effect of scrambling encryption of the algorithm.

Mots clés

  • chaotic sequence
  • images
  • scrambling
Accès libre

A Scene Recognition Algorithm Based On Multi-Instance Learning

Publié en ligne: 01 Dec 2014
Pages: 1470 - 1492

Résumé

Abstract

In Bag of Words image presentation model, visual words are generated by unsupervised clustering, which leaves out the spatial relations between words and results in such shorting comings as limited semantic description and weak discrimination. To solve this problem, we propose to substitute visual words by visual phrases in this article. Visual phrases built according to spatial relations between words are semantic distrainable, and they can improve the accuracy of Bag of Words model. Considering the traditional classification method based on Bag of Words model is vulnerable to the background, block and scalar variance of an image, we propose in this article a multiple visual words learning method for image classification, which is based on the concept of visual phrases combined with Multiple Instance Learning. The final classification model is able to show the spatial features of image classes. Experiments performed on standard image testing sets, Caltech 101 and Scene 15, show the satisfying performance of this algorithm.

Mots clés

  • Image Classification
  • Multiple Kernel Learning
  • Bag of Visual Words
  • Spatial Pyramid Matching
Accès libre

Face Alignment Based On Semi-Active Appearance Mode

Publié en ligne: 01 Dec 2014
Pages: 1493 - 1515

Résumé

Abstract

In the information era, the technology of biological character recognition has attracted more and more attentions. In this paper, by investigating theories of active appearance model and inverse compositional image alignment algorithm, we mainly proposed a semi-active appearance model for face alignment based on improving the classical models in the aspects of computation complexity, easily suffering from light, angle and expression, and so on. Firstly, the model of active appearance and the algorithm of alignment are investigated. For the inefficiency of classic gradient descent method in the matching process, the inverse compositional image alignment algorithm is proposed. Then, through combining the active appearance model and Grey Level Co-occurrence Matrix, a novel semiactive appearance model is proposed, which has a simple calculation and higher accuracy of face alignment. Finally, experiments were designed to demonstrate the effectiveness of the proposed algorithms.

Mots clés

  • face alignment
  • active appearance model
  • inverse compositional alignment
  • grey level cooccurrence matrix
Accès libre

Research and Restoration Technology of Video Motion Target Detection Based on Kernel Method

Publié en ligne: 01 Dec 2014
Pages: 516 - 1534

Résumé

Abstract

In recent years, due to the video surveillance applications more and more widely, people are not satisfied with the goal of monitoring, and the video monitoring technology of intelligent video moving object detection and tracking technology has received extensive attention. The research work in this paper is in the field, the moving target detection spatiotemporal correlation and difference contour tracking algorithm based on a fixed background. The algorithm in the background under the condition of fixed to pay a smaller time complexity, the target detection and tracking has a good effect, so it has higher application value. In this paper, the prospect of caused motion detection of occlusion background foreground correlation problem, put forward the video moving object detection method based on kernel independent component analysis, canonical correlation to minimize the component in the high dimensional feature space in order to separate the foreground nuclear background. Independent component analysis assumes that the foreground and background independent, avoid the correlation problem. The two objective functions based on Kernel Independent Component Analysis: analysis of kernel independent component analysis based on kernel canonical component (KCCA) and kernel independent component analysis (KGV) based on the generalized variance. KCCA is the application of canonical correlation analysis in the kernel method, discuss is the first canonical correlation separation component of high dimensional map, and KGV are typical correlation between the components in the high dimensional space of the whole spectrum. Both KCCA and KGV improved the accuracy of motion detection.

Mots clés

  • Moving object
  • kernel method
  • active
  • pattern recognition
  • image features
Accès libre

A Self-Adaptive Data Balance Protocol For Distributed Radio Frequency Identification Sensor Network

Publié en ligne: 01 Dec 2014
Pages: 1535 - 1554

Résumé

Abstract

In this paper, we share our recent work related to Radio Frequency Identification (RFID) sensor network with readers. The work mainly focus on the protocol for network system to perform the task of autonomous decentralized data distribution with consideration of economic and low-power RFID-sensor module scheme. We analyzed data pitfall in distributed RFID-sensor network, revealing the reason lies in the phenomenon. A distributed solution to tackle the problem has been designed in a simple way. The test results show that the system with proposed approach provides an efficient and more balanced in data distribution which proves the protocol is feasible for the application scenario.

Mots clés

  • RFID Sensor network
  • equal probability scheduling
  • stochastic switching
  • Galton effect
Accès libre

Design and Construction of Light Weight Portable Nmr Halbach Magnet

Publié en ligne: 01 Dec 2014
Pages: 1555 - 1578

Résumé

Abstract

A light weight, simple design NMR apparatus consists of 24 identical magnets arranged in Halbach array was designed and built. The homogeneity of the magnetic field B0 can be improved by dividing a long magnets into several rings. The size of the useful volume depends on both the gap between each ring and some others shim magnets. Our aim is to enhance the sensitive volume and to maintain the highest magnetic static field (B0). This apparatus generates a B0 field strength of about 0.1 T. This work focuses on the magneto-static simulation of NdFeB magnets arrangement and on the comparison with the measurement of the magnetic field strength and homogeneity in three dimensions (3D). The homogeneity of the magnetic field B0 is optimized with the help of CAD and mathematical software. Our results were also validated with a Finite Element Method (FEM). The simulation results of the strength and of the homogeneity of B0 field were compared to those obtained with a digital gaussmeter. The homogeneity in the magnet longitudinal axis and the field B0 strength are similar. However, the homogeneity in transverse plane differs from simulation and measurement because of the quality of the magnets. In order to improve the homogeneity, we propose a new shim method.

Mots clés

  • Nuclear Magnetic Resonance (NMR)
  • Low field
  • Portable Permanent Magnet
  • Halbach
  • Shim magnets
  • Homogeneity
  • Simulation
  • Finite Element Method (FEM)
Accès libre

Simulation of the Leakage Effect In Capacitive Sensing

Publié en ligne: 01 Dec 2014
Pages: 1579 - 1594

Résumé

Abstract

In the measurement of mutual capacitance between electrodes both the coupling and the leakage effect contribute to the measurement result whereas the leakage mode is dominant in the selfcapacitance mode. While the coupling effect is mainly defined by the geometry and material distribution close to the electrodes, the root cause or modulation of the leakage effect may be far away from the electrode. In this paper we demonstrate that the leakage mode concept allows for simulation of 3D problems in 2D. This is useful in applications such as Electrical Capacitance Tomography or object classification as it allows simplifying the computational complexity while providing additional information compared to the classical 2D approach.

Mots clés

  • leakage effect
  • capacitive sensing
  • open environment
  • ECT
  • reconstruction
Accès libre

Measurement And Analysis Of High Temperature Using Distributed Fiber Optic Sensor

Publié en ligne: 01 Dec 2014
Pages: 1595 - 1612

Résumé

Abstract

In this paper the working principle and application status of distributed optical fiber temperature sensor, amplified spontaneous Raman scattering phenomenon and its time-domain characteristics are analyzed. A new measuring principle based on amplified spontaneous Raman scattering light pulse signal temperature effect is presented, and is applied to distributed optical fiber sensor systems. Noise inevitably exists in data collected by distributed optical fiber temperature sensing systems. According to the needs of high-temperature oil well testing, distributed high temperature single-mode fiber sensors and detection equipment are designed, and gives two-dimensional data of oil well temperature testing. Because of the weak Raman backwards scattered signal and serious noise disturbance, multi-resolution wavelet analysis and reconstruction method are adopted for the denoising of testing signal.

Mots clés

  • Fiber optic
  • Sensor
  • Digital signal processing
  • Temperature control
Accès libre

Multi-Agv Scheduling Optimization Based on Neuro-Endocrine Coordination Mechanism

Publié en ligne: 01 Dec 2014
Pages: 1613 - 1630

Résumé

Abstract

To solve the problems of task scheduling and coordination control presented by a multi-AGV system, the mixed regional control model for the production task has been advanced. The architecture of multi-AGV task assignment and scheduling mechanism has been proposed by combining the mixed regional control model for the production task and the neuro-endocrine coordination mechanism. Hormones for manufacturing cell are secreted by the machine tool according to the information in the production task, and the task can be allocated to the most suitable machine according to the hormone concentrations of the manufacturing cell. The AGV’s hormones are secreted according to the AGV’s operation state. The AGV with the largest hormone concentration will be chosen to execute the transportation task, thus shortening the overall run time of the system. A series of scheduling simulation experiments are performed for some specific examples to demonstrate the feasibility and efficacy of the proposed approach. The results show that tasks can be allocated according to the current status of a machine tool and tasks can be scheduled according to the current state of the AGV system to maximize the efficiency of the AGVs as well as that of the overall system.

Mots clés

  • multi-AGV
  • scheduling strategy
  • coordination control
  • neuro-endocrine coordination mechanism
  • scheduling simulation
Accès libre

Orientation Of A Triaxial Accelerometer Using A Homogeneous Transformation Matrix And Kalman Filters

Publié en ligne: 01 Dec 2014
Pages: 1631 - 1646

Résumé

Abstract

The evolution in the development of manufacturing techniques of electronic components, including accelerometers, has allowed access to a new field of research and applications in consumer electronics. The aim of this work is to present a method for aligning triaxial accelerometers, finding the parameters of the rotation, the translation and the scale of the homogeneous transformation matrix. In principle, it is necessary to acquire six points to build the frame of reference of the accelerometer and ensure the consistency of the measurements, in order to check the angle between the axis and the magnitude. Subsequently, using spatial geometry, the intersection of the system of reference is estimated, to determine the extent of translation in the homogeneous transformation matrix. In a further step, the rotation values of the matrix are generated by taking the orientation of the z-axis into account and, finally, the resulting factor is scaled to normalize the magnitude value of gravity. Using the transformation matrix, it is possible to align the original reference system of the accelerometer to another coordinate system. The satisfactory results of this experiment show the need of implementing the here described method to enable the use of variable tilt measurements.

Mots clés

  • Accelerometer
  • alignment
  • tilt
  • translation
  • triaxial
  • rotation
Accès libre

Design Of A Four-Wing Heterogeneous Fractional-Order Chaotic System And Its Circuit Simulation

Publié en ligne: 01 Dec 2014
Pages: 1647 - 1662

Résumé

Abstract

Integer orders differential system is a special case of fractional-order differential system. Integer orders chaotic system that we usually study is ideally approximate to realistic chaotic system. Fractional-order chaotic system has broader and changeable values of order and more complex dynamical behavior than integer order chaotic system. Thus, fractional-order differential equation can describe the nonlinear characteristics of actual chaotic system more exactly, which has more prominent research meanings and application value. This paper designs a new four-wing four-dimensional heterogeneous fractional-order chaotic system, when the values of fractional-order qi(i =1,2,3,4) are not identical( q1 = q2 = 0.9, q3 = q4 =0.8, in step size of 0.1), the attractors of this chaotic system will all show four-wing shapes in any direction. After analysis this chaotic system’s stability and existence, this paper also introduces a nonlinear state feedback controller, and adopts the chain shape circuit to conduct experiment simulation through Multisim software 10.0. The results of circuit simulation and Matlab numerical operation have the same chaotic attractor phase diagram. This demonstrates the effectiveness of this four-wing four-dimensional heterogeneous fractional-order chaotic system’s design and the feasibility of the feedback controller in the circuit; meanwhile, it provides referable bases for the application in actual circuits.

Mots clés

  • Fractional-order differential system
  • chaotic system
  • heterogeneous fractional-order
  • circuit simulation
  • feedback control
Accès libre

Connectivity-Aware Topology Control With Cyclic-Like Structures In Wireless Sensor Networks

Publié en ligne: 01 Dec 2014
Pages: 1663 - 1682

Résumé

Abstract

Connectivity offers the foundation for achieving required quality of service in all WSN applications. By the concept of cyclic-like topologies proposed and their property proved, we find a new searching method based on cyclic paths on nodes and their combination, which cuts down the cost of ensuring bi-connectivity in this problem. On the basis of graph and probability theory, our centralized connectivity-aware algorithm with cyclic-like topologies and computation of link reachability is proposed. Results of the experiments show that, our topology control algorithm could be more satisfactory than that of another two algorithms in different scales of networks.

Mots clés

  • Wireless Sensor Network
  • connectivity
  • topology control
  • fault-tolerant
  • cyclic-like topologies
  • biconnected
Accès libre

Applications Of Compressive Sensing Over Wireless Fading Channels

Publié en ligne: 01 Dec 2014
Pages: 1683 - 1700

Résumé

Abstract

Wireless fading channels exist mixed noise, the most common noises are gaussian noise and impulse noise, to ensure the quality of the received signal, removing the noise in the channel is very important and necessary. WSDN (wavelet soft-threshold de-noising) can suppress low-intensity gaussian noise well; unfortunately, the denoising effect in removing impulse noise using WSDN is not obvious, especially when noise intensity is relatively high. BPDN (Basis Pursuit Denoising) which is a reconstruction algorithm of compressive sensing can control high-intensity gaussian noise in the channels well preceding WSDN, but also the effect of BPDN denoising the common impulse noise is not obvious, to denoise impulse noise, we adopt IBPDN (Improved Basis Pursuit Denoising) that changes L2 form to noise to L1 form, which was proposed in 2006 by Guosheng Bing. The experimental data show that IBPDN has good anti-noise ability to both gaussian noise and impulse noise; furthermore, more satisfactory results are obtained using IBPDN to mixed noise than those with BPDN.

Mots clés

  • IBPDN
  • BPDN
  • WSDN
  • Wireless fading channels
  • denoising
Accès libre

Research Of Multi Sensor Intelligent System Signal Fusion And Reconstruction

Publié en ligne: 01 Dec 2014
Pages: 1701 - 1716

Résumé

Abstract

This paper studies some key technology of multifunctional sensor signal reconstruction. The multifunctional sensor signal reconstruction problem, presented a multifunctional sensor signal reconstruction method based on B spline and the extended Caiman filter. The method of inverse model of the process was studied, gives a method to estimate signal reconstruction accuracy and computation. Genetic algorithm is proposed to balance the multifunctional sensor signal reconstruction accuracy and computation based on. In order to further reduce the sampling effort of large quantities of multifunctional sensor signal reconstruction, is proposed based on the reduction method clustering multifunctional sensor sample selection method, to select the reasonable distribution, suitable for inverse training data model. A new direction to study the theory of multi sensor information fusion is to design and analysis more efficient processing of multi sensor intelligent system is proposed and developed. With the continuous improvement of the intelligent system requirements, research on information fusion of multi-sensor system is affected by the people more and more attention.

Mots clés

  • Multi-sensor
  • signal reconstruction
  • complex
  • sample detection
Accès libre

Research On Wtg Power Performance Monitoring Methods Of Regional Wind Power Group

Publié en ligne: 01 Dec 2014
Pages: 1717 - 1735

Résumé

Abstract

With growth of the wind power scale and the increasing of urgent requirement on operating life extension of units followed with which, how to monitor regional wind power group automatically and find recession performance of WTG power so as to take measures timely to restore the health condition and reduce power losses has become an important problem to be solved by wind farm operators. Horizontal and longitudinal performance comparison methods of the power characteristics for the same area and model units are proposed in this paper. Different real-time monitoring and analysis methods are used. The core technology of which is using wind speed partitioning technology and Wavelet analysis. Longitudinal power performance monitoring comparison method of single-unit is used as a further preferred aspect scheme of information fusion. Research results are verified by Matlab simulation platform. The study results integrated with the developed centralized monitoring system software, can improve the efficiency of wind farm operation and monitoring in large degree, further ensure the profitability production for wind farm plants.

Mots clés

  • Regional wind power group
  • Bin method
  • Wavelet analysis
  • Horizontal and longitudinal comparison
  • Power performance monitor
Accès libre

Zigbee Transmission Power Dynamic Adjustment System Based On Fuzzy Control

Publié en ligne: 01 Dec 2014
Pages: 1736 - 1752

Résumé

Abstract

We designed a fuzzy controller for ZigBee equipment’s transmission power adaptive adjustment. The controller is based on RSSI (Received Signal Strength Indicator). It can make a dynamic adjustment on the transmitted power according to the fuzzy control rules. The fuzzy control is suitable to solve the problem which is difficult to deal with in building system mathematical model. What’s more, the fuzzy control system has perfect performance in response speed and antijamming capability. It’s convenient to embed in devices. In this paper we use Ti Company’s CC2530 chip as an experiment object. By using the fuzzy controller we keep the transmission power to the minimum. By this way, the energy consumption can be reduced on the premise of ensuring normal communication. The fuzzy controller system has a good steady-state and dynamic performance, and contributes to the ZigBee system’s stability and low power consumption performance.

Mots clés

  • fuzzy control
  • ZigBee
  • RSS
  • CC2530
  • low power consumption
Accès libre

Research On Underwater Target Signal Detection And Recognition Processing Algorithm

Publié en ligne: 01 Dec 2014
Pages: 1753 - 1772

Résumé

Abstract

Practical application of underwater target echo signal usually get disturbed a Gaussian noise and non-Gaussian noise, in view of the signal recognition problem, this paper proposes a double spectrum analysis based on wavelet transform domain method of weak signal and D-S data fusion algorithm. Through the study of double spectrum of the wavelet transform domain analysis to the signal processing algorithm, the characteristics of the target signal and noise source signal, a processing method of underwater target signal de-noising was presented. For multiple underwater target recognition, the model of underwater target multi-sensor signal recognition was studied. On the basis of analyzing the principle of D-S method and the fusion of multiple signal recognition, the concrete measures of D-S data fusion reasoning was researched and analyzed. By using the combination of simulation calculation and experiment measures, the results show the signal processing method is correct.

Mots clés

  • wavelet transforms
  • the double spectrum analysis
  • signal recognition
  • data fusion
Accès libre

Numerical Analysis of Sliding Friction Coefficient and the Normal Pressure Between the Cable Wire

Publié en ligne: 01 Dec 2014
Pages: 1773 - 1788

Résumé

Abstract

In this paper, the wire pressing device is designed, the range of true positive pressure, curves of steel friction coefficient changes with positive pressure. Describe the change trend of friction coefficient is: with the increasing pressure, friction coefficient of cable parallel wire decreased significantly, but when the pressure increases to a certain value, the friction coefficient decline is slowing down, and finally tends to a certain value. The curves of friction coefficient changes with positive pressure, provides a method and basis for the practical engineering of steel wire in the ultimate friction shear stress accurately, set up and stay cable as layered slipping model provides important parameters of bending stress analysis. From the numerical simulation method analyzes the positive pressure parallel wire between the start. This paper first parallel wire contact problem of two cables are analyzed with the classical theoretical solution and the FEM software ANSYS, to verify the feasibility, using ANSYS to solve the contact problem of accuracy and precision. On this basis, the strand steel beam of contact analysis, the preliminary inquiry arching effect on cable parallel wire.

Mots clés

  • Stay cable
  • positive pressure arch effect
  • mechanism
  • friction coefficient
  • ANSYS
  • contact analysis
Accès libre

The Smart Home System Based on the Iap15F2K61S2 and Gsm

Publié en ligne: 01 Dec 2014
Pages: 1789 - 1806

Résumé

Abstract

At home, there are all kinds of electrical devices. Also the gas may leak to fire. Once the danger happens, it will result in the huge losses. The smart home system is necessary for the safety. The system integrated the sensors to monitor the appliances whether they work normally. Once the exceptions have been tested, the owner can get the text massage immediately with the help of GSM. This system has a light cube. It has 512 lights. After test, this system works to monitor the home appliances very well at the low cost.

Mots clés

  • IAP15F2K61S2
  • GSM
  • the smart home system
Accès libre

Face Recognition Based On Improved Support Vector Clustering

Publié en ligne: 01 Dec 2014
Pages: 1807 - 1829

Résumé

Abstract

Traditional methods for face recognition do not scale well with the number of training sample, which limits the wide applications of related techniques. We propose an improved Support Vector Clustering algorithm to handle the large-scale biometric feature data effectively. We prove theoretically that the proposed algorithm converges to the optimum within any given precision quickly. Compared to related state-of-the-art Support Vector Clustering algorithms, it has the competitive performances on both training time and accuracy. Besides, we use the proposed algorithm to handle classification problem, and face recognition, as well. Experiments on synthetic and real-world data sets demonstrate the validity of the proposed algorithm.

Mots clés

  • Face recognition
  • biometric feature
  • Support Vector Clustering
  • kernel methods
  • classification
  • large-scale data
Accès libre

Centralized Discrete State Space Model Predictive Control And Decentralized Pi-D Controller Of An Aerothermic Process

Publié en ligne: 01 Dec 2014
Pages: 1830 - 1849

Résumé

Abstract

The aerothermic process is a pilot scale heating and ventilation system equipped with a heater grid and a centrifugal blower. The interaction between its main variables is considered as challenging for mono-variable controllers. A change in the ventilator speed affects the temperature behavior which represents a factor that must be managed for energy saving and the human welfare. This paper presents an experimental comparison between a Centralized Discrete State Space Model Predictive Control (CDSSMPC) and a Decentralized PI-D (DPI-D) controller. These both techniques are designed by using respectively the Laguerres functions and the static decoupler approach. To demonstrate the effectiveness of the two methods, an implementation on an aerothermic process is performed. This pilot scale is fully connected through the Humusoft MF624 data acquisition system for real time control. The results show satisfactory performance in closed-loop of the DPI-D controller compared to the CDSSMPC and the conventional PID ones.

Mots clés

  • Centralized discrete state space model predictive control
  • Laguerre functions
  • Static decoupler
  • Decentralized PI-D controller
  • Multivariable systems
  • Aerothermic process
Accès libre

A Framework For “Energy-Saving Strategies”: Utilization of A cue Offering Interface

Publié en ligne: 01 Dec 2014
Pages: 1850 - 1869

Résumé

Abstract

Mass consumption of energy is a big problem. Energy-saving activities which are a solution to this problem have been attracting a lot of attention. Nevertheless, in order to engage in thorough energy-saving activities, consumers need support; on the other hand, even with support, the effects seem to be only temporary. In this paper, to obtain a long-term effect, we focus on developing a method to raise consumers’ awareness about energy-saving behavior. To this end, we designed an interface which offers consumers the cue to think about energy-saving activities and conducted a 2week-experiment using the interface with 10 participants. The results suggest two things. First, offering cues increases the number of the energy-saving activities. Second, the more times they perform an activity, the less likely it is that they will change their way of thinking about the activity as time passes. We discuss a more effective method of helping consumers create energy-saving strategies.

Mots clés

  • energy-saving activity
  • human interface
  • cue offering
  • sound
  • eco-feedback
Accès libre

Film Thickness Measurement Of Mechanical Seal Based On Cascaded Artificial Neural Network Recognition Model

Publié en ligne: 01 Dec 2014
Pages: 1870 - 1889

Résumé

Abstract

Mechanical seal end faces are separated by a thin fluid film. The thickness of this film must be optimized so as to preventing the serious friction of two end faces and minimizing the fluid leakage. The micro scope condition monitoring of end face is of importance to ensure mechanical seals run normally. A method for measuring the film thickness of end faces and detecting the friction of end faces of mechanical seal has been presented in this paper. Eddy current sensors embedded in the stationary ring of mechanical seals are used to directly measure the thickness of the liquid-lubricated film. The Eddy current signal is decomposed by empirical mode decomposition into a series of intrinsic mode function. The information reflecting the film thickness is obtained by eliminating the false intrinsic mode function components. Acoustic emission sensor placed on the lateral of stationary ring is used to detect the friction of end faces. In order to decrease the acoustic emission signal’s noise, wavelet packet and kernel principal component analysis are used to extract the data features. Then cascaded decision is presented to improve the recognition rate of artificial neural network, by which the film thickness can be estimated accurately. With a set of tests, the results demonstrate that the method is effective. It can be widely used to take measurement of the film thickness in industrial field.

Mots clés

  • Mechanical Seal
  • Film Thickness
  • Eddy Current
  • Acoustic Emission
  • Empirical Mode Decomposition
  • Artificial Neural Network
Accès libre

Coverage Holes Recovery Algorithm Based On Nodes Balance Distance Of Underwater Wireless Sensor Network

Publié en ligne: 01 Dec 2014
Pages: 1890 - 1907

Résumé

Abstract

Underwater wireless sensor network nodes deployment optimization problem is studied and underwater wireless sensor nodes deployment determines its capability and lifetime. Underwater wireless sensor network if no wireless sensor node is available in the area due to used up energy or any other reasons, the area which is not detected by any wireless sensor node forms coverage holes. The coverage holes recovery algorithm aiming at the coverage holes in wireless sensor network is designed in this article. The nodes movement is divided into several processes, in each movement process according to the balance distance and location relations move nodes to separate the aggregate nodes and achieve the maximum coverage of the monitoring area. Because of gradually increasing the balance distance between nodes, in each movement process the nodes moving distance is small and reduce the sum of the nodes movement distance. The simulation and experimental results show that this recovery algorithm achieves the goal of the nodes reasonable distribution with improving the network coverage and reducing the nodes movement distance thus extends the lifetime of the network in the initial deployment phase and coverage holes recovery phase.

Mots clés

  • Coverage Holes Recovery
  • Nodes Balance Distance
  • Wireless Sensor Network
Accès libre

Sound-Separation System using Spherical Microphone Array with Three-Dimensional Directivity—KIKIWAKE 3D: Language Game for Children

Publié en ligne: 01 Dec 2014
Pages: 1908 - 1921

Résumé

Abstract

Mixed sounds can be separated from multiple sound sources using microphone array sensor and signal processing. We believe that promotion of interest in this technique can lead to significant future development in science and technology. To investigate this technique, we designed a language game for children called “KIKIWAKE 3D” that uses a sound-source-separation system to arouse children’s interest in this technology. However, the microphone array sensor in a previous research had a limited scope in separating sounds. We developed a spherical microphone array sensor with three-dimensional directivity designed for this game. In this paper, we report the evaluation of this microphone array sensor in adapting to this game by separating the sound level and using questionnaires.

Mots clés

  • Supporting learning system
  • signal processing
  • frequency-band selection
  • implementation
  • and evaluation
Accès libre

Improving The Localization Of Electric Wheelchair By Using Particle Filter

Publié en ligne: 01 Dec 2014
Pages: 1922 - 1942

Résumé

Abstract

The electric wheelchair for handicapped is used to improve the displacement of disabled persons. An automatic navigation system is needed to ensure greater autonomy and security for the disabled person. Automatic control system is added to a manual control for autonomous displacement. Initial system composed of two DC motors installed at the rear of used electric wheelchair, power module for the motors control and joystick to select speed and moving direction. We include an automatic control system composed by two electronic cards, based on microcontrollers CB405 and PIC16F877 for the signal acquisition from the encoders and distance measurements from ultrasonic sensors (SRF08 and SRF04). The ultrasonic sensors used to improve the localization when we use an automatic control system. Several techniques exist for sensors fusion solves the problems of mobile robots localization. Among these methods, we can quote the particle filter that use data from the encoders and measures from the ultrasonic sensors.

Mots clés

  • electric wheelchair
  • encoder
  • ultrasonic sensors
  • particle filter
  • power module
  • microcontroller
  • CB405
  • PIC16F877
Accès libre

Adaptive Mobile Anchor Localization Algorithm Based On Ant Colony Optimization In Wireless Sensor Networks

Publié en ligne: 01 Dec 2014
Pages: 1943 - 1961

Résumé

Abstract

In wireless sensor networks (WSNs), node’s locations play a critical role in many applications. Having a GPS receiver on every sensor node is costly. In this paper, we propose an adaptive mobile anchor localization algorithm based on ant colony optimization, firstly, some virtual anchor nodes are distributed in the area, second, ant colony was used which has the maximum of transition probabilities to obtain the optimal path, last, the centroid-weighted localization algorithm was proposed to locate the position of unknown nodes. Simulation results show that the localization accuracy of the proposed algorithm is better than the traditional centroid algorithm, the more number of anchor nodes, namely, the density is bigger, the position errors is smaller. Under the same anchor nodes, the more number of unknown nodes, the position errors is smaller and the overall trend is downward.

Mots clés

  • Wireless sensor networks
  • mobile anchor
  • ant colony optimization
  • localization algorithm
  • centroid-weighted
Accès libre

Security Method For Combination Steganography Algorithms On Transform Domain For Jpeg Images

Publié en ligne: 03 Dec 2014
Pages: 1962 - 1979

Résumé

Abstract

Steganography is the act of hiding a message inside another message in such a way that can only be detected by its intended recipient. In any communication, security is the most important issue in the world today. It created a lot of data security and steganography algorithms in the past decade, and that worked motivation for our research. In this paper, Security Method for Combination Steganography Algorithms on Transform domain for JPEG images, we have designed a system that will allow the average user to securely transfer secret messages (picture) securely by hiding them in JPEG image file using local characteristics within the image. This paper is a combination of two steganography algorithms, which provide a strong backbone for its security. The proposed system hides the image unrevealed manner through the use of steganography algorithms to protect each other, where was used F4 algorithm as a wall to protect outguess01 algorithm. We combine between steganography algorithms (outguess 0.1 algorithm and F4 algorithm) to make use of it to provide more than level of protection for the secret message (image). When save the secret message (image) within an image by using outguess01 algorithm, Which produces outguess-image, then hide outguess-image within another image by using F4 algorithm, Which produces F4-image(stego image). Adopt the principle of camouflage and deception to hide image gives another level of safety for secret Image. Good selection of size and type images used in the process of concealment that contributed to the success of the process of embedded and retrieval of hidden images. Results proved after calculating the capacity and PSNR for images that a good and acceptable steganography scheme. The model presented here is based on JPEG images.

Mots clés

  • Transform domain technique
  • OutGuess0.1 algorithm
  • F4 algorithm
  • peak-signal-to-noise ratio (PSNR)
Accès libre

The Effects Of Lumber Seasonal Growth Rings On Microwave Measurements

Publié en ligne: 01 Dec 2014
Pages: 1980 - 1996

Résumé

Abstract

In order to determine more accurate indicators of wood structure obtained by microwave sensing and improve our understanding of plane wave propagation through this complex material, we have undertaken a permittivity survey and experimentally investigated scattering of a plane wave, measuring its transmission over two non-parallel surfaces of a rectangular lumber sample. This novel non-destructive testing technique offers results which may significantly contribute in a more accurate propagation modeling and industrial wood quality testing.

Mots clés

  • microwave
  • non-destructive testing
  • free-space transmission measurement
  • wood
Accès libre

Sharing Research Experiences Of Wsn Based Smart Home

Publié en ligne: 01 Dec 2014
Pages: 1997 - 2013

Résumé

Abstract

We are pursuing our research on ZigBee based WSNs for more than 8 years; a lot of realization stories are conveyed in literature on the development of wireless measurement of sensors data using ZigBee (XBee RF module). Many projects are fruitfully completed for applications such as smart home for elder care, environmental monitoring, big building monitoring and so on. Still a lot of design issues are there while the systems are designed using ZigBees. In this research paper the working experiences which may support other researchers to achieve success without wasting resources are reported. Moreover, presented research analyses of some unusual observations made in a proto-typed smart home monitoring system have been discussed. Packet delivery ratio (PDR) and latency are among a few reliability issues that have been analysed and addressed in this article to make the system more robust.

Mots clés

  • Smart sensors
  • wireless sensor network
  • wireless sensors
  • measurement
  • instrumentation
  • XBee and IEEE 802
Accès libre

Optimal Techniques For Sensing Error Minimization With Improved Energy Detection In Cognitive Radios

Publié en ligne: 01 Dec 2014
Pages: 2014 - 2034

Résumé

Abstract

Spectrum sensing, the problem of detecting the presence of licensed user in the channel is considered in this paper. Energy detection is best suited for the spectrum sensing when prior knowledge about the primary users is unavailable. Existing works report improved versions of energy detection which primarily focuses on maximizing the detection performance. Sensing error minimization is an important aspect of spectrum sensing that needs attention. This paper focuses on the sensing error minimization of the improved energy detection algorithm in which the decision statistic is computed using an arbitrary positive index instead of squaring operation. First, an optimum decision threshold satisfying Minimum Error Bound (MEB) is derived. Next, an optimum value of the arbitrary positive index with minimum number of samples satisfying a Target Error Bound (TEB) is derived. A thorough numerical analysis and simulations are performed and the results confirm the accuracy of the analysis.

Mots clés

  • Spectrum sensing
  • Cognitive radio
  • Energy detection
  • Threshold optimization
  • Sensing error

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