Showing papers in "Communications Technology in 2009"

Character Recognition Based on Template Matching Method

Abstract: An algorithm based on pattern matching method is proposed for characters recognition systemsThe characters are normalized by the character pretreatmentThe feature extraction of characters is realized,the characters are divided into a number of small collectionsFinally,the algorithm makes judgments according to the results of the template matching in the range of small character collectionsThe results show that the template matching algorithm ensures the accuracy of character recognition,and the characters pre-classification could reduce the character searching range and save the time

IEEE802.11p:Wireless Access in Vehicular Environments

Abstract: Vehicular safe communications applications could not tolerate long connection establishment delays before being enabled to communicate with other vehicles encountered on the road. Additionally, the rapidly moving vehicles and complex roadway environment present great challenges at the PHY level. The research of IEEE 802.11p is based on IEEE 802.11 solutions for vehicular networks. For the design of original IEEE 802.11 standard is no good in flexibility, the IEEE802.l1p working group mainly addesses such problems as frequent disconnection and handover, including new safety problem. This paper gives an overview and general applications of IEEE802.11p.

Overview on RFID Technology and Application

Abstract: Radio frequency identification (RFID) is a new automatic identification technology,and achieves rapid development both at home and abroad. The composition,principle,standardization,and the development and applications of RFID technology,are reviewed respectively,and the applications of RFID technology in logistics,anti-fake and traffic management are also described. From these,the people could understand,and thus apply RFID technology even better.

An Approach for Video-text Extraction based on Text Traversing Line and Stroke Connectivity

Abstract: In the complicated background,conventional automatic video-text location methods can not robustly locate text.A novel video-text location method is proposed in this paper.It falls into two stages:in the first stage,an unsupervised paradigm based on wavelet is applied to obtain candidate text region;in the second stage,traversing line with its amplitude spectrum is introduced and applied to create boundary for each text line.Experiment indicates that this scheme can robustly locate the text of various colors,fonts,and sizes in the complicated background,and performs better than schemes in [5] and [7].

Algorithm Study on Cell Search in LTE

Abstract: A detailed algorithm design for initial cell search in LTE system is proposed,which includes timing synchronization,frequency offset estimation,blind detection type of cycle prefix,cell ID and cell ID group identifying and frame synchronizationAnd among these,the timing synchronization,frequency offset estimation and cell ID identifying are accomplished by primary synchronization signal in time-domain,while blind detection type of cycle prefix,the cell ID group identifying and frame synchronization achieved by secondary synchronization signal in frequency-domainBoth the theory analysis and simulation results show that the algorithm proposed has good performance both in AWAG and multipath fading channels,and can satisfy the performance demand by cell search in LTE system

Channel Estimation Method for OFDM Systems

Abstract: Channel estimation for orthogonal frequency division multiplexing(OFDM) systems is very important when it is used in mobile communication field. The cascade one-dimensional channel estimation method is analyzed,and a modified method,by means of windowing and based on DCT(EIDCT),is proposed. The simulation performance of the modified algorithm is given,and the simulation result of the modified algorithm is also analyzed. All this proves the effectiveness and efficiency of this proposed method.

RFID Application in Tourism Scenic-spot Automatic Ticketing System

Abstract: Based on analysis of the current tourism scenic-spot ticketing system and by combining RFID with the characteristics of the current automatic ticketing machines,a RFID automatic ticketing system is proposed. The system mainly consists of automatic ticket vending machines,ticket machines,back-office server and other modules. This system could,through standarded communications interfaces,provide real-time touristry flow,ticketing,and other processing information for the network management center,thus improving informatization and automation of tourism scenic-spot management. Experiment indicates that the system meets the design requirements and is simple,fast,convenient and safety.

Wavelet Transform Based Symbol Rate Estimation of MPSK Signals

Abstract: By analyzing the wavelet domain character of MPSK signals, the symbol rate estimation algorithms of MPSK signals in combination of wavelet transform with FFT is studied, and the performances of between two symbol rate estimation algorithms by using once the wavelet transform or twice the wavelet transform are compared. The simulation results show that the twice wavelet algorithm is superior to the once wavelet algorithm, and the precise extraction ratio of the signal symbol of MPSK signals in up to 98% on condition of RSN ≥ 5dB.

A Dynamic Password Identity Authentication System Based on Mobile Phone Token

Abstract: With the improvement of wireless network, there are increasing users wirelessly accessing the Internet through mobile phones So it is very important to solve the identity authentication problems of wireless access users Dynamic password has become the new development trend for the Identity Authentication mechanism It offers stronger security than the static password In this article, a dynamic password authentication protocol based on callenge/rsponse mechanism is designed According to this protocol, a dynamic password identity authentication system based on mobile phone token is designed The composition and authentication processes of this system are described in detail, and its security is analyzed as wel1 The analysis indicates that this system features high security and wide application It can be conveniently used and implemented in low cost

Design on Wireless Transceiver System Based on nRF905 Module and AT89S MCU

Abstract: Based on the description of the structure and working features of RF transceiver nRF905 module,a wireless transceiver system based on nRF905 module and AT89S MCU is designed.The hardware circuit and the complete transceiver flow charts are given in the paper,and the data transceiver experiment has proved that the design of the system is effective and reliable.Finally,the application of this transceiver system is discussed in detail.

Analysis on Allpass System Function of Warped Discrete Fourier Transform

Abstract: The allpass function of WDFT (Warped Discrete Fourier Transform) is comprehensively analyzed with the method of zero-pole decomposing. Under the condition that the warped parameters are all real,frequency is warped at the real axis,and the warped point couldn’t be changed by these parameters. This article specifically analyzes the second-order allpass function. High-order allpass function is also referred and analyzed accordingly.

Design of Zigbee Gateway System Based on ARM

Abstract: This paper presents the design of an gateway in Zigbee wireless senor network based on Arm9 Processor. The core of gateway hardware is STR912, which intergrates Ethernet MAC and the CC2430 wireless module. The proposed application address adaptive and protocol layers make the data exchange between Zigbee and Ethernet network transparent, and also make it easy to expand to other network. In brief, this design satisfies the efficiency and transparency requirement of the data exchange while realizes the extensibility.

Design and Implementation of Intelligent Transportation Systems Based on GPS/GPRS

Abstract: In the light of public transport management at home and abroad, the actual situation and the development of GPS technology, and for those mature intelligent transportation system which have not integrated GPS, GPRS and GIS in order to realize information collection, receiving/sending, and displaying of the vehicle location, an intelligent transportation system based on GPS, GPRS and GIS technology is designed. This paper describes in detail the structure and composition of the system, including its working principle. This system realizes the GPS-based real-time traffic information collection, GPRS-based wireless information transmission, and GIS-based remote monitoring of vehicle movement.

A Cooperative Locating Algorithm Based on Least Square and Taylor Series Algorithm

Abstract: A new cooperative locating algorithm based on least square and Taylor series is presented.The outcome of the least square algorithm is used as the initial value of Taylor series in the cooperative locating algorithm,thus to over come the difficulty in choosing initial value when Taylor series algorithm is adopted during the cellular network radio positioning.The simulation results indicate that this algorithm has achieved better performance on positioning accuracy and efficiency than the least square and Taylor series algorithm.

Research and Design of PKI-based IPsec-VPN Security

Abstract: Although the use of IPSec in virtual private network (VPN) is a good network security solutions and the Internet Protocol Security is significantly improved, the network security in complicated environment, due to its lack of perfect identity authentication, is seriously affected.As a publicly trusted platform , PKI is composed of public key technology,digital certificates,CA and security strategy, which can provide identity authentication and role access control service. This paper gives a scheme for applying PKI into IPSec-VPN to strengthen identity authentication and access control mechanisms, thus making the security of VPN more perfect more secure.

Simulations of A Quasi-Yagi Planar Antenna Working in 3GH

Abstract: The planar microstrip-fed quasi-yagi antenna has shown excellent radiation characteristics over a wide frequency band. In this paper, a quasi-yagi planar antenna working in 3GH is described. The radiation characteristics of this antenna are very good, with a front-to-back ratio 18db and cross polarization level -18db.These performances have been confirmed by FTDT simulations.

Design of Smart Home System Based on Wireless Sensor Network

Abstract: Wireless sensor networks collect information of environmental or monitoring targets by using various integrated micro-sensors as real-time monitor.The master home system is designed by using a equal home neural network to control every in-time equipment.In this paper,home equipment monitoring and controlling system is designed based on the wireless sensor networks.This article gives the specific design scheme of every system module,and also describes the flow of system implementation.

Reconstruction of Normal Speech from Whispered Speech based on BP Neural Network

Abstract: This paper tells of a new approach for reconstructing normal speech from Chinese whispered speech based on BP neural network.First,the formants of normal speech and whispered speech are acquired,and the BP neural network is used to get a model of the conversion from the whispered speech to the formants of normal speech,then the formant of whispered speech is converted by adopting this model.Finally,the whispered speech is converted into the normal speech by using the formant synthesizer.Simulation results show that the score of the DRT of the converted speech is 80% and the MOS is 3.5,both intelligibility and quality of the converted speech are satisfied.

Remote Diagnosis of Locomotive Engine’s Mischief Based on GPRS in Embedded Internet

Abstract: In order to effectively monitor and diagnose the mischief of locomotive operation and gearing installation,a remote diagnosis system for locomotive engine based on embedded Internet of GPRS is designed The composition of this system is briefly described,the remote communication technology based on resonance demodulation and embedded Internet of GPRS for realizing system functions is emphatically analyzed,and diagnostic resource sharing is realized to the maximum Even if the mischief vibration amplitude of locomotive engine is less than 550 dB,the information is transmited as usual to the ground control centre and the delay is less than 3 seconds,thus the success rate of real-time diagnosis is almost up to 100%

Research Situation on Routing Protocols in Wireless Sensor Networks

Abstract: This paper mainly studies wireless sensor network routing from two aspects:the fundamental train of thought for designing wireless sensor network routing and the security issues of wireless sensor network routing.It sums up the development of wireless sensor network router,and finally looks into the future of routing protocol for wireless sensor network.

Orthogonal Frequency Division Multiple Access and Its Application in IEEE802.16-2005

Abstract: Orthogonal frequency division multiple access(OFDMA), which has a high bandwidth availability, is a new multiple access based on OFDMIn this paper, the principle of OFDMA is described and its application to mobile broadband wireless access is presented with focus on the channel coding, link adaptation technology, multi-antenna technology

New Algorithm For Computing Network System Reliability

Abstract: This paper studies the reliability evaluation of 3-state devices network. BDD is a diagrammatic representation of Boolean function. In this paper, a modified BDD algorithm for finding disjointed minimal paths set of network reliability is proposed, and a new algorithm for computing 2-terminal reliability of 3-state devices networks system is obtained by using reduction formulas. The algorithm is the most excellent in the same kinds of methods. It effectively eliminates the redundant terms of the reliability expression, and is with less nodes in 1-0 branching tree, thus acquiring efficient symbolic expression of reliability.

Performance Analysis of IPSec VPN Based on OPNET

Abstract: Simulation and analysis of network performance by OPNET simulation software could reduce the cost of network design,performance study and development while raise the design efficiency and make data statistics and analysis easy and convenientThe paper principally describes the flow of network simulation and the modelingIn addition,the performance of IPSec VPN in IPv6 environment is analyzed through the experiment with OPNET software

Design and Analysis on Dual-band Multilayer Microstrip Antenna

Abstract: A dual-band,multilayer microstrip antenna is designed and analyzed in this paper.High and low stacked patches,three-layer dielectric materials and probe-fed structure are introduced into the design of the antenna.The antenna is simulated by the software HFSS 10.0.The simulation results indicate that the frequency channels of the antenna are 1.31GHz-1.39GHz and 1.86GHz-1.94GHz,the relative bandwidths are also available,and so it could be used in radio frequency band as dual-band antenna.

Array Antennas Beam Pattern Synthesis Based on Neighborhood Particle Swarm Optimization

Abstract: Array signal processing is a rapidly developing technique,and optimization of beam pattern synthesis is an important issue of this technique.Particle swarm optimization could achieve excellent results with simple computing.Neighborhood particle swarm optimization,uses the neighbor particles past best positions,besides the particle personal best positions and the global best positions,to updates the particle next new position,thus eliminating the standard particle swarm optimization's easiness for converging to local optimal value.Experiment indicates that,by this modified algorithm,the beam pattern synthesis for array antennas could achieve excellent results.

Research on Real-time Transport Technology of Multimedia Data Flow

Abstract: With the increasing demand of real-time business, the technology for real-time multimedia transport is developing vigorously. In this paper, several key technologies for real-time multimedia transport, such as RSVP, RTP, RTSP, IPv6, are reviewed. Also, their principles and functions are described in detail. Finally, the implementation and the development of real-time multimedia transport are discussed.

Identity Authentication Technology and Its Development Trend

Abstract: As a core technology of the information security,identity authentication technology is to identify and verify the user's legality and authenticity in information system.This article describes the identity authentication technology and also tells of such emerging technologies as quantumn identity authentication,IBE,thinking authentication,behavior authentication and automatic authentication.

Application of CSSD and AAR in EEG Signal Processing

Abstract: Identification and classification technology plays an important role in the study of brain-computer interface(BCI) system.In this paper,a new algorithm is proposed to deal with the complex brain signals,extract features and classify single-trial electroencephalogram(EEG).The proposed algorithm combines CSSD algorithm and adaptive autoregressive(AAR) model with linear discrimination analysis to extract features from multi-channel EEG.This algorithm is applied to Data Set I of BCI Competition III.The experiment results show that the proposed method could classify EEG signals with high accuracy.

Study of Elliptic Curve Cryptography

Abstract: Elliptic curve cryptography(ECC) is a kind of public key algorithm,which uses the difficult solution of discrete logarithm question on the point group of elliptic curve. This article focuses on ECC,studies elliptic curve cryptography from an angle of data encryption,and discusses in detail the elliptic curve cryptography. Finally,this article sums up some applications of elliptic curve system in several fields.

Adaptive Algorithm for Beam Forming of Smart Antenna

Abstract: The smart antenna adaptive algorithms achieve the best weight vector for beam forming by iterative operation. If adaptive algorithms could achieve faster convergence and lower steady-state error, the performance of beam forming would be much better. In this paper, an improved adaptive algorithm is proposed for beam forming. The proposed algorithm combines variable step size algorithm and transform-domain algorithm. The simulation with MATLAB indicates that the proposed algorithm for beam forming is better than other conventional algorithms, and could achieve faster convergence and lower steady-state error.