bluuebunny/crossref_metadata_2025 huggingface dataset:
The Noise Fault Analysis and Exclusion in Self-Propelled Transporter Hydraulic System
Authors: Cheng Fei , Zhao Jing Yi , Guo Rui , Sun Bing Yu
Published: August 2013

Noise is one of the common faults in hydraulic system. The correct analysis and deal with the noise will make for the normal operation and optimization of the system. In view of the noise of a new self-propelled transporter suspension hydraulic system produced in the debugging process of the heavy load lifting when suspension falling, by means of mechanism analysis, modeling and simulation analysis of the suspension hydraulic system, finding out the noise comes from the hydraulic component of system with SV type pilot check valve; The noise fault is caused by the improper circuit design of hydraulic system, the feasibility of the using the SL type pilot check valve to eliminate suspension hydraulic system noise proved by the simulation analysis, in the field test of the improved suspension hydraulic system, the suspension falling gentle and noise elimination, which shows that the analysis and simulation model is correct; Through the comparison and analysis on the SV type and SL type kinds of pilot check valve on the reasonable application in the hydraulic circuit isolation, that provides a theoretical basis for the correct selection two kinds of pilot check valve.
Research on Load Models Effect on Stability of Voltage of DC End Power System
Authors: Liu Xiao Ming , Niu Xin Sheng , Zhang Jie , Zhu Yi
Published: August 2013

Load characteristic is one of the vital factors that effect the stability of voltage of power system. As the most important dynamic load in power system, induction motor is one of the most direct reasons which resulting in instability of voltage. In simulated analysis, the establishment of load model, choice of parameter as well as ratio distribution of different kinds of load will lay considerable influence on the stability of system. This thesis establishes the load model of induction motor in stable and transient state and simulates on the basis of Shandong power grid. As the simulating result shows, load ratio of induction motor has fundamental effect on the voltage stability of Shandong power grid. As the load ratio of induction motor increases, the stability of voltage of Shandong power grid decrease and the voltage may even break down.
Wind Generator Model for Fault Diagnosis
Authors: Wang Wei , Yu Hai Fang , Zheng Chang Fu , Zhao Yan Shi
Published: August 2013

In order to make a diagnosis of wind turbine failure, the mathematical model of the wind turbine should be prepared. This model can provide a theoretical basis for fault diagnosis. establishing the mathematical model of the main part of the generator being discussed on theoretical ,including the tower vibration, wind wheel and drive chain, the moment of inertia of the wind turbine and the synchronous generator voltage equation model in dq coordinate system. Its main focus on the demand for wind turbine fault diagnosis.
Microgrid Harmonic Suppression Method Based on One Cycle Controlled Active Power Filter
Authors: Wang Ji Dong , Qin Mei Cui
Published: August 2013

With widely research and application of microgrid, the effect of the harmonic problems becomes not be ignored. This paper applies one cycle controlled active power filter (APF) to suppress harmonic in microgrid. Compared with traditional methods, one cycle controlled APF omits the harmonic detecting circuit and greatly simplifies the system structure. The one cycle control method in this paper, combining with space vector control, divides the frequency cycle into three control sextants, which simplifies the controller further. This paper builds the model of one cycle controlled APF and microgrid model including wind power system and photovoltaic systems. Then make simulation analysis about microgrid harmonic suppression. Simulation results show that one cycle controlled APF has a good compensation effect in microgrid harmonic suppression.
Modeling and Parameter Sizing of Battery/Ultra-Capacitor Hybrid Energy Storage System Used in HEV
Authors: Yu Hai Fang , Wang Wei , Ge Yu Lin , Liu Zhi Qiang
Published: August 2013

It has been shown that none of any energy sources which own high specific energy or high specific power, but not both, can solely fulfil all the demands of hybrid electric vehicle (HEV) in some circumstances. In this paper a simulation model for battery/ultra-capacitor hybrid energy storage system (B/UC HESS) was presented by Matlab/Simulink. Based on the model a parameters sizing principle of the energy storage system is put forward from the angle of energy and power respectively. The results show that following this parameters matching principle, the B/UC HESS can meet the double requirements for power and energy in the operation process of HEV. Whats more, a good foundation is laid for HEV parameters optimization of the energy storage sources. The experiment results also show that the buffering effect of ultra-capacitor has optimized the charging and discharging processes of Ni-MH battery considerably.
A Design of High Frequency Clock Generation Circuit
Authors: Zhai Yan Nan , Gao Ling , Tang Yan Kun , Li Jing , Luan Shuang
Published: August 2013

A clock generation circuit is proposed based on CMOSFET technology, which is comprised of a reference voltage source, a common source voltage amplifier, voltage controlled oscillator and timing circuit. By which a particular clock is produced, whose duty cycle is less than 50%. It is used 0.5 μ s CMOS process, HSPICE simulation results indicates that the average frequency of clock signal is 2.071MHz, and the average duty cycle is 31.565% .
4.5kV SiC JBS Diodes
Authors: Tao Yong Hong , Huang Run Hua , Chen Gang , Bai Song , Li Yun
Published: August 2013

High voltage 4H-SiC junction barrier schottky (JBS) diode with breakdown voltage higher than 4.5 kV has been fabricated. The doping level and thickness of the N-type drift layer and the device structure have been performed by numerical simulations. The thickness of the device epilayer is 50 μm, and the doping concentration is 1.2×1015 cm3. A floating guard rings edge termination has been used to improve the effectiveness of the edge termination technique. The diodes can block a reverse voltage of at least 4.5 kV, and the on-state current density was 80 A/cm2 at VF =4 V.
The Design of Human-Machine Interface for Rudder Control System Monitoring Platform Based on WinCC
Authors: Dang Yang , Wang Hong Bo , Liu Ting Wei , Yang Shu Ren , Zhao Yong Gang
Published: August 2013

This paper describes a Human-Machine interface for rudder control system based on WinCC. This interface contains the dynamic monitoring screen for rudder control system, and it can communicate with PLC and WinCC. The Human-Machine Interface has an overview schematic of steering system, and there are five sub-screens in the overview schematic including Unit screen, Measure screen, Alarm screen, Trend screen and Table screen. The display patterns of data are virtual dashboard and curves, and it can be recoded, saved and printed. The system achieves the communication between PLC and WinCC by using OPC. Experiments demonstrated that setting up a monitoring platform for industrial production achieve a visual monitoring, data acquisition and display effectively.
High Breakdown Voltage GaN HEMT Device Fabricated on Self-Standing GaN Substrate
Authors: Zhou Jian Jun , Li Liang , Lu Hai Yan , Kong Ceng , Kong Yue Chan , Chen Tang Sheng
Published: August 2013

In this letter, a high breakdown voltage GaN HEMT device fabricated on semi-insulating self-standing GaN substrate is presented. High quality AlGaN/GaN epilayer was grown on self-standing GaN substrate by metal organic chemical vapor deposition. A 0.8μm gate length GaN HEMT device was fabricated with oxygen plasma treatment. By using oxygen plasma treatment, gate forward working voltage is increased, and a breakdown voltage of more than 170V is demonstrated. The measured maximum drain current of the device is larger than 700 mA/mm at 4V gate bias voltage. The maximum transconductance of the device is 162 mS/mm. In addition, high frequency performance of the GaN HEMT device is also obtained. The current gain cutoff frequency and power gain cutoff frequency are 19.7 GHz and 32.8 GHz, respectively. A high fT-LG product of 15.76 GHzμm indicating that homoepitaxy technology is helpful to improve the frequency performance of the device.
Design of Building Electric Energy Saving
Authors: Wang Xiang Ning , Chen Ying , Li Jing
Published: August 2013

With the rapid development of the construction industry, people pay more and more attention to the huge energy consumption of buildings. To promote energy-saving design is the only way to improve the present situation. The electric lighting accounts for 15% ~25% of the total consumption of buildings, which directly affect the effect of energy saving. Therefore, to promote energy-saving design of the electric lighting, such as using natural light, using efficient energy-saving light source, using reasonable lighting system, using efficient lighting control system decreasing the invalid energy consumption of the electric lighting system itself and so on is really the key to decrease the energy consumption level of buildings.
Study of Embedded Operating System Process Scheduling
Authors: Zhang Jin Hai
Published: August 2013

Embedded systems are widely used in industries, its amazing to develop speed and as an embedded system software for embedded operating system is at the core of the information industry research hot spots. This thesis is mainly embedded in different application environments, the operating system discussion and research on how to implement its process scheduling algorithm.
An Improved Channel Estimation Method in OFDM System
Authors: Li Shun Xian
Published: August 2013

In this paper, we will focus on channel estimation (CE) in orthogonal frequency-division multiplexing (OFDM) systems. The time-varying (TV) channelsare modeled by a basis expansion model (BEM). Due to the time-variation, the channel matrix in the frequency domain is no longer diagonal, but approximately banded.We use a pilot-aided algorithm for estimation of rapidly varying wireless channels in OFDM systems. Theperforms is goodwhen the channels vary on the scale of a single OFDM symbol duration, which occurs in mobile communication scenarios such as WiMAX, WAVE, and DVB-T.We recover Fourier coefficients of the channel taps by the pilot information.We then estimate the BEM coefficients of the channel taps from their respective Fourier coefficients using a recently developed inverse reconstruction method.We compare some BEM models in inverse methodsto find out the best ones in certain conditions.
Design for Realizing Arbitrary Fractional Divider Based on FPGA which Duty Cycle is up to 50%
Authors: Zhang Song Wei , Zhao Cheng
Published: August 2013

This paper proposes a novel method for realizing arbitrary fractional divider based on FPGA. Analyzing the limitations of the existing frequency-divided methods, a new model which consists of two-level dividers is put forward. An arbitrary frequency-divided clock output can be obtained by this method approaching 50% of duty cycle. When the division factor is greater than 128, the duty cycle can be very close to 50% of the clock output. This method is proved to be feasible on the FPGA chip of ALTERA.
Fabrication of L Band 4H-SiC SIT Devices
Authors: Chen Gang , Jiang Hao , Zhong Shi Chang , Bai Song
Published: August 2013

Silicon carbide (SiC) static induction transistors (SITs) were fabricated using home-grown epi structures. The gate is a recessed gate - bottom contact (RG - B). The mesa space designed is 2.5 μm and the gate channel is 1.0 μm. The developed devices adopted a p-type Al ion implanted gate and power performance was improved by decreased leakage current and enhanced break-down voltage. The lift-off with assistant dielectric, dense gate recess etching, high temperature anneals and PECVD passivation process technologies are adopted. One cell has 200 source fingers and each source finger width is 50 μm. 0.5 mm SiC SIT yield a current density of 110 mA/mm at a drain voltage of 50 V. A maximum current density of 160 mA/mm was achieved with Vd = 80V, and the maximum transconductance is 40mS/mm. The device blocking voltage with a gate bias of-12 V was 400 V. Packaged 2 × 2-cm devices were evaluated using amplifier circuits designed for class AB operations. A total power output in excess of 70 W was obtained with a power density of 17.5 W/cm and gain of 5.5 dB at L band 1 GHz under pulse 100μs and cycle ratio 1% RF operation and 80V drain to source voltage.
An SC-FDMA Channel Estimation Algorithm Research Based on Pilot Signals
Authors: Xue Jian Bin , Li Song Bai
Published: August 2013

SC-FDMA as LTE uplink main technology has been widely studied,at the same time, channel estimation around such technology is becoming hot,In order to research and increase channel estimation accuracy of LTE uplink system,an algorithm based on pilot is proposed in this paper,this algorithms main idea is,by setting a certain bit error rate,choosing some proper data after channel estimation done under R-LS and M-MMSE, combining the chosen data and former block pilot and increasing pilot number to do channel estimation again, system bit error rate and mean square error results can be got by simulation;at last,the theoretical analysis and simulation results show that this algorithm really can make the channel estimation accuracy improved and bit error rate decreased.
A Compact Ultra-Wideband Monopole Antenna with Dual Bandstop Characteristics
Authors: Li Wen , Wang Jun Jun , Sun Yan Chao , Meng Xian Chao
Published: August 2013

A compact and simple ultra-wideband microstrip-fed planar antenna with double bandstop characteristic is presented. The antenna consists of a rectangular monopole and two W-shaped slots inserted into the radiating patch and the truncated ground plane. By using a W-shaped slot defected ground structure (DGS) in the feedline, a stopband of 800 MHz (from 5.1 to 5.9 GHz) for band rejection of wireless local area network (WLAN) is achieved. To obtain the other stopband (from 3.7-4.4 GHz), a same shaped slot is etched into the monopole. Moreover, the two stopbands can be controlled by adjusting the length of the slot respectively. The simulation results show that the designed antenna, with a compact size of 38.5 mm×42.5 mm, has an impedance bandwidth of 2.811 GHz for voltage standing wave ratio (VSWR) less than 2, besides two frequency stopbands of 3.74.4 GHz and 5.15.9 GHz. Moreover, the main features including omnidirectional H-plane radiation patterns and the appropriate impedance characteristic are achieved by beveling the radiating patch and the microstrip-fed line of the proposed antenna.
A Secure and Energy-Efficient Rooting Protocol for WSN
Authors: Bi Jia Na , Xu E
Published: August 2013

In directed diffusion rooting protocol, interest and exploratory data are disseminated by flooding, which will bring broadcast storm resulting in substantial energy consumption of wireless sensor networks. Grid-based directed diffusion rooting protocol can improve energy efficiency where geographic grids are constructed by self-organization of nodes using location information. Flooding of interest and exploratory data is limited in grid head nodes. But grid-based directed diffusion rooting protocol considers less about security. To adapt to environments with high security requirements, traffic attack detection and secure data aggregation schemes are added to grid-based directed diffusion rooting protocol. Simulation shows that the proposed schemes can real-time predict traffic attacks and improve accuracy of data aggregation results when networks are under attacks. At the same time, the protocol consumes less energy and extends lifetime of networks.
Development of Embedded Practice Platform for Control System Based on ARM
Authors: Liu Qing , Wei Jiang Tao
Published: August 2013

This paper uses an industrial control product as a teaching platform, the necessary foundation of theoretical teaching and practical exercises which is combined, so that students quickly grasp the embedded industrial control system software and hardware, the basics of the system hardware and software analysis, circuit testing, and has strong ability to application. It can improve students on the practical aspects of the initiative and enthusiasm by courses. Improve the requirements of the course on the basis of the original experiment, the validation and repeated cross-experiment is deleted, which is contributed to save hours and improve efficiency. Due to the application of advanced processing technology, so it can reduce the distance of the school teaching and social applications.
Optimal Power Consumption Analysis of Two-Level Hierarchical Model and Non-Hierarchical Model
Authors: Zhang Gang Lin , Liu Guang Can , Chen Wei Bing , Yang Cheng
Published: August 2013

Energy scarcity is one of the most critical problems that occur in wireless sensor networks compared to traditional networks. However, the problem has been partly solved by building the power consumption model of WSN. This paper is based on a simple wireless sensor network model, it gives the optimal location of the CH nodes in a cluster and the best parameter about how to divided the cluster amongst hierarchy networks. As shown last, the proposed scheme can save up to 95% of power consumption.
Improvement on LEACH Protocol of Wireless Sensor Network
Authors: Ma Xiao Wen , Yu Xiang
Published: August 2013

Wireless sensor networks comprise of minor battery driven devices with restricted energy resources.Once installed,the minor sensor nodes are usually unapproachable to the operator, and thus auxiliary of the energy source is not practicable.Hence,energy proficiency is a vital design issue that needs to be boosted in order to increase the lifetime of the network. LEACH is a popular hierarchical routing protocol which efficiently maintains the energy storage of nodes in Wireless Sensor Network (WSN).The nodes using LEACH are divided into clusters.The advantage of LEACH is that each node has the equal probability to be a cluster head,which makes the energy dissipation of each node be relatively balanced. This paper studies LEACH protocol, and focuses on how to decide the next hop nodes more reasonable when the data are transmitted at the steady state. Simulation has been done in NS2 and the results show that the algorithm after improved is more energy-efficient than LEACH protocol.
Analysis of MMSE-Based Anti-Interference Performance for MIMO-UWB Systems
Authors: Yan Biao , Wang Jia Min , Guo Ding Ping , Cai Sai Yan
Published: August 2013

The combinations of MIMO (Multiple-Input-Multiple-Output) and UWB (Ultra-Wide-Band) systems greatly improve the performance of the UWB system. For the MIMO-UWB system, a new decoding scheme is proposed based on the STF (Space-Time-Frequency) coding and it can reduce the decoding complexity. The simulation results show that under the same SNR, the new method can obtain better performance of the bit error rate than the traditional ML decoding method.
The Analysis of Transient Grounding Resistance of Portable Horizontal Grid Earth Electrodes
Authors: Qu Xin Bo , Zhou Bi Hua , Cao Ning Sheng , Fu Ya Peng , Huang Xiao Gang
Published: August 2013

Based on current situation of mobile equipments earth devices, a new type of portable horizontal grid earth electrode has been designed. With the impulse ground measurement system, different number of earth electrodes responses to double exponential pulse current have been tested on cement grounds. Impulse waves of voltage and current have been gotten by experiments, and the curve of Transient Grounding Resistance (TGR) can be calculated. The analysis of discharging capacity of horizontal grid earth electrodes in time domain has great significance in the design of mobile equipments earth devices.
Design of Unsymmetrical Doherty Power Amplifier for 460MHz LTE-Advanced Applications
Authors: Ma Chuan Hui , Pan Wen Sheng , Tang You Xi , Qing Chao Jin
Published: August 2013

An unsymmetrical Doherty power amplifier (DPA) at 460MHz is presented in this paper. The carrier and peaking amplifier of the DPA, which base on two equal-sized devices, are matched with different networks to mitigate the performance degradation caused by the limited load modulation. Measured with continuous wave (CW), the unsymmetrical DPA saturates at an output power of 49.2dBm and achieves a drain efficiency of 51% at 6dB back-off. Using a one-carrier long term evolution advanced (LTE-Advanced) signal with 20MHz bandwidth, the unsymmetrical DPA exhibits a drain efficiency of 48.7% at an average output power of 42.1dBm, along with adjacent channel leakage ratio (ACLR) of-34.1dBc and-53.3dBc before and after digital pre-distortion (DPD), respectively.
A Reliable Cooperative Spectrum Sensing Strategy for Cognitive Radios
Authors: Lv Shou Tao , Dai Ze Yang , Liu Jian
Published: August 2013

In cognitive radio networks (CRNs), the secondary users (SUs) need to continuously detect whether the primary users (PUs) occupy the spectrum. In order to improve the spectrum sensing accuracy, a novel reliable cooperative spectrum sensing strategy based on the detection results relayed twice from the secondary relays (SRs) to the secondary source (SS), referred to as CSS-DRT, is proposed in this paper. In this scheme, the spectrum sensing slot is divided into four equal sub-slots. In the first and third sub-slots, the SS and SRs detect the PU by themselves. Then, in the second sub-slot, if the SRs that detect the PU during the first sub-slot are more than or equal to a prespecified quantity, the corresponding SRs will send their flag signals (FSs) to the SS while the others keep quiet, where the FS is narrowband and indicates that the PU is present. Otherwise, if the SRs that detect the PU during the first sub-slot are less than the prespecified quantity, all the SRs will keep quiet in the second sub-slot. Meanwhile, the SS detects the PU based on the received signals from the PU and SRs. And, the SS uses the same method as employed in the second sub-slot to detect the PU in the last sub-slot wherein the SRs send their FSs based on their detections made during the third sub-slot. Finally, an ultimate decision is made by the OR ruler based on the SS detection results obtained during the spectrum sensing slot. Besides, we derive the closed-form expressions of the false alarm and detection probabilities for the proposed CSS-DRT scheme. In the end, simulation and numerical results show that our proposed scheme can achieve better performance than the non-cooperative method and an existing cooperative spectrum sensing method.
Design of ARM Based Embedded Operating System Micro Kernel
Authors: Qu Bo , Wu Zhao Zhi
Published: August 2013

This paper describes the design and implementation of an ARM based embedded operating system micro kernel developed on Linux platform with GNU tool chain in technical details, including the three-layer architecture of the kernel (boot layer, core layer and task layer), multi-task schedule (priority for real-time and round-robin for time-sharing), IRQ handler, SWI handler, system calls, and inter-task communication based on which the micro-kernel architecture is constructed. On the foundation of this micro kernel, more components essential to a practical operating system, such as file system and TCP/IP processing, can be added in order to form a real and practical multi-task micro-kernel embedded operating system.
Research on the Distribution Automation System Based on IEC61850
Authors: Xin Hong Wang , Ding Qiao Lin
Published: August 2013

In order to solve interoperability of the distribution automation devices and Plug and Play issues, propose intelligent power distribution model based on IEC61850, Stratifie according to the method of information: Master level,feeder layer,the terminal layer,device layer, layer monitoring. Use the face of the object model of the distribution automation IED, at the same time, use abstract communication service independent of the specific communication technology model ACSI, Establish distribution network automation system communication system Follow the IEC61850 standard.
Study of Overvoltage Protection and Insulation Coordination for MMC Based HVDC
Authors: Gu Yi Lei , Huang Xiao Ming , Qiu Peng , Hua Wen , Zhang Zhe Ren , Xu Zheng
Published: August 2013

This paper focus on overvoltage protection and insulation coordination in Modular Multilevel Converter based HVDC system planning. An overvoltage protection scheme, which bases on the topology used inTransbay project by Siemens, is proposed in this paper. Thescheme draws fromthe characteristics of MMC-HVDC systems and the research results in classic HVDC systems, byplacing arresters at some key locations in the MMC-HVDC converter station.With this scheme, the overvoltage at those key pointscan be limitedto an acceptable range and hence protect the key equipment concerned. Since all the DC lines of the project are undersea cables, no lighting overvoltage is considered and 14 faults which could happen are carefully selected to serve as the verification conditions for the insulation design. Based on the PSCAD/EMTDC simulations and the deterministic method, the specified withstand voltage levels of the critical equipment in the converter station is calculated.
Analysis of Low Frequency Oscillation in Power System
Authors: Chu Xiao Rui
Published: August 2013

Around the type of power system of the low frequency oscillation, the mechanism of production, the analysis methods, the analysis tools and suppression method, etc, it summarized the research status of low frequency oscillation of power system. Therefore, based on this research status, the future analysis methods and developmental trend of the low frequency oscillation of power system were discussed.In the power system, the angle of attack among generators, the voltage on the nodal points and the tidal current of junctor and so on had the constant-amplitude or the increased range vibrates, and the oscillation frequency (generally is 0.2~2.5 Hz) is lower than the system frequency. This oscillation form is called the low frequency oscillation[1]. Then the frequency of the low frequency oscillation is low, cycle to be longer,and affected area to be wide, it is also big harm to the power system. Therefore, at present, studying low frequency vibration has the even more important meaning[2].
An Improved Multistage Variable-Step MPPT Algorithm for Photovoltaic System
Authors: Wang Ping , Zhou Zhe , Cai Meng Meng , Zhang Jing Bin
Published: August 2013

This paper presents an improved multistage variable-step incremental conductance method to achieve the maximum power point tracking (MPPT). Compared with the traditional variable-step incremental conductance method, this improved algorithm optimizes the selection of the step size so that the tracking of the maximum power point is more quickly and the steady-state performance is better. Furthermore, the algorithm can still guarantee the quickness and accuracy of MPPT when the environmental conditions change suddenly and tremendously. At last, matlab simulation was applied to compare the characteristics of multistage variable-step algorithm with that of the other. And the simulation results verified that the improved algorithm has better dynamic and steady-state performance.
The Design and Implementation of USB Mass Storage and CCID Composite Device
Authors: Zhang Wei , Zhang Jin Nan , Zhang Yang An , Lu Bin
Published: August 2013

USB disk and UKEY are common applications of USB Mass Storage and CCID protocol and used widely in our daily life, but they are always deployed on different kinds of devices such as USB disk and UKEY. A potential application that integrates the functions of these two protocols into one device is discovered by us. In this way, we can regard a single device as a mass storage and an UKEY as well. According to this discovery, a new Mass Storage and CCID composite device is developed on IS8U192A development board. After this, several tests are made with some test tools to ensure the newly developed device is able to function well and the Mass Storage and CCID protocols are accurately implemented.
Performance Analysis of Coherent Atmospheric Optical Communications with Soft-Decision Forward Error Correction
Authors: Tao Jin Jing , Zhang Jin Nan , Zhang Yang An , Huang Yong Qing , Yuan Xue Guang , Li Yu Peng
Published: August 2013

Performance of coherent atmospheric optical communication system with heterodyne detection and LDPC codes was evaluated over atmospheric channel attenuations of which are about 20-30 dB/km. To reduce bit error and enhance the system performance LDPC code was implemented in system. Combining coherent detection and LDPC codes could reduce the received power requirement ~4 dBm at the BER of 10-9.
An Application of LDPC Code for Wireless Coherent-Light Commutation in Atmospheric Channel
Authors: Hao Ning , Zhang Yang An , Zhang Jin Nan , Zhang Ming Lun , Yuan Xue Guang
Published: August 2013

Low Density Parity Check code is more and more taken seriously in high-speed transmission. In this article we represent a LDPC coder and decoder which based on IEEE802.16e and realize the coder and decoder with Virtex-5 FPGA. By using Matlab to make an off-line system simulation, we analyzed and compared the LDPC performance under the different length of code for LDPC coder then analyzed the influence of different iteration to the LDPC BER performance of decoder.
Simulation and Analysis of Transmission Performance of JTIDS
Authors: Shi Jian Sheng , Song Mao Zhong
Published: August 2013

As a very important part of Link-16, Joint Tactical Information Distribution System (JTIDS) has a good performance. In this paper, the primary technologies of JTIDS are presented and their Transmission performance are simulated and analyzed. And in the different conditions, the bit error rate simulation is tested based on the rationale of JTIDS. In the end of this paper, anti-jamming ability of JTIDS is simulated and the results show that JTIDS has high performance of anti-jamming.
The Design and Implementation of the Surveillance and Control System for Photovoltaic Power Station
Authors: Wang Jian , Song Shu Ting , Zhang Yong , Gao Feng
Published: August 2013

According to the characteristics of PV power station, how to present a new intelligent surveillance and control system of PV power station, which collects the operating parameters at real-time and control the running status of the PV power station through wireless networks and the Internet, to guarantee the security, stability and economic operation of grid-connected PV system, becomes a problem which electric power enterprises have to be solved urgently. Based on the analysis of several remote monitoring technology projects which are general practical in PV system, the article designs a set of photovoltaic power plant monitoring system aimed at the security, stability of grid-connected PV system, which is described from the ideas of construction, software architecture, and development of hardware and so on.
Researches of Pressure Measurement Method in Vacuum Environment
Authors: Wu Hou Ya , Yang Tie Niu , Wang Xiao Jun
Published: August 2013

wafer processing is one process of the IC industry which is a booming area nowadays, the quality of the production of this course depends on the performance of the film which is formed by deposition. And one of the most important factors influencing the performance is working pressure. Variable structure chamber for flowing experiment and testing which is a multifunction testing platform with changeable structure and sufficient measurement points all-covered the chamber, a device has been designed and manufactured to measure and research vacuum flow filed. By using this equipment, the pressure in vacuum chamber could be measured precisely and promptly, thus relationships among the size and shape of the chamber, the pressure, and the gauges would be clear, there would be helpful for vacuum measurement. Background The course of manufacturing a chip of IC production including 400~500 processes which could be divide into two categories: wafer processing which is FEOL (front-end-of-line) and chip packaging which is BEOL (back end of line), as it illustrated in Fig. 1. Wafer manufacturing is a process of exacting and refining high purity silicon (usually 99.999%) from silica; Wafer processing is depositing a thin film (among 100umto 22nm, according to the requirement and depending on technology) which contains required elements on the face of the original wafer; Dicing is chipping out wafer into little blockages to face different requirement; Assemble and packaging is fabricating chip into IC component. During the course of Wafer processing, the working condition is usually under low velocity, high vacuum and high temperature condition (depends on the characteristics of sediment), take the projectDeposition of Hydrogenated Amorphous Siliconas an example---- 5.0sccm, 11.0~16.0mtor, and 250°C[1]. The performance of wafer is decided by the nature of reactors and the processing condition of which a little change would lead a different property of the production. Thus it is necessary and imperative to figure out the relationship among the factors influencing depositing process. And the most important among these factors are pressure, velocity, and temperature. In this paper, a method of pressure measurement based on a device of variable structure chamber for flowing experiment and testing will be introduced. Fig. 1, Semiconductor manufacturing process
Design of Terahertz-Wave Transmission Imaging System
Authors: Pei Jie , Chen Gang
Published: August 2013

An imaging system based on the transmission and reflection modes in the terahertz (THz) region is developed by using a backward-wave oscillator (BWO) as source, a Golay-Cell as detector, and an oscilloscope as data acquisition unit. The system software based on the oscilloscope is designed to control the object movement, and the capture and display of the continuous THz wave image data. The imaging of different objects is tested at the frequencies of 450 GHz and 890 GHz to show the validity of the imaging system at room temperature. The influence of objects humidity and thickness, incident wavelength, and translation step on the THz imaging is discussed in details.
Research and Improvement of Fourier Algorithm in the Microcomputer Relay Protection
Authors: Xu Jian , Yao Xin
Published: August 2013

Fourier algorithm can be effective utilized in the Microcomputer relay protection to filter out Harmonic component in the AC signal .but the drawback is that not filter attenuation DC component. it may be affect the computation accuracy of the entire system .and it is also reduce the efficiency of the system. In this paper ,we combined with the actual project ,on the basis of analysis of the full-wave Fourier algorithm ,for the problem of it can not filter decaying a periodic component ,we proposed an improved algorithm, and combined with MATLAB simulation ,the results show that the improved algorithm has the advantages of high accuracy and the algorithm is simple.
In the microcomputer relay protection of the power system need to handle all kinds of signals, provide the necessary information for the implementation of protection. however, With the rapid development of computer technology and the continuous research of computer algorithms, a lot of actual power system protection device has been widely used in our life, on the one hand, these devices reduce the complexity of building hardware circuit, on the other hand ,it can make full use of the filter function about some algorithms have itself. The most important is that it can avoid the problem of instability and low efficiency with some filter circuit. But, this characteristic need the algorithms has a high precision [2,3].
The algorithm is set up in the microcomputer protection is a mathematical model for achieve some specific function. and write the corresponding computer applications according to this model. Then do some specific mathematical operations with these digital signals will achieve the purpose of protection. At present, the widely used full wave Fourier algorithm has a function of filtering DC component and harmonic component[4],but it can not filtering the decaying DC component in the system. It will be cause a certain interference and influence to the whole system in the practical application, the result is that led to the precision of the operation drop and lose the meaning of the protecting. In this paper, combined with specific engineering example give an improved calculation method. Through example of simulation has proved that using this algorithm can accurately figure out fundamental component and harmonic component, and it has the advantage of algorithm simple and high accuracy [5].
Timing Acquisition with Cooperation of Two Distributed Receive Antennas over Flat-Fading Channels
Authors: Qing Chao Jin , Wei Jin Cheng , Xia Ling , Liu Ying , Ma Chuan Hui , Tang You Xi
Published: August 2013

In the flat Rayleigh channels of linear cell, two distributed receive antennas are employed to receive the signal transmitted from the mobile station (MS) with a single antenna. We exploit the false alarm probability at the central processor to guarantee that the false alarm probability at each distributed antenna does not exceed the pre-defined probability of false alarm. Based on the exploited probability of false alarm at the central processor, a cooperative detection threshold of each antenna is derived for threshold detection. According to the threshold detection, a maximum-likelihood (ML)-based timing acquisition method is proposed for distributed antenna systems (DAS). Without increasing the pre-defined probability of false alarm, the analysis and simulation results show that the correct acquisition probability and the missed detection probability for each distributed antenna can be improved with the proposed method wherever the MS is located.
Research on Online Measurement Method of Hole Diameter and Position
Authors: Gong Yu , Zhang Jing Cai , Liu Hong Qi
Published: August 2013

In this paper, research on measurement methods of hole during the parts online detection has been made. Both diameter and position of the hole are going to be detected in the same measurement system. In order to obtain higher accuracy and efficiency, a comparative analysis test of using the contact probes, the inductive sensor, the laser sensor, the forward and back lighting CCD imaging have been achieved. Results show that the contact measurement using inductive sensor is more suitable for the system, for the reason that it has higher reliability and efficiency.
Constructing IPv6 with Small Local Network
Authors: Wang Bao Qin , Zhang Wen Jing , Zhou Xu Yang
Published: August 2013

To spread IPv6 to the end of the networks, it is necessary to construct networks used for small organizations. In fact, few researchers would disagree with the understanding of active IPv6 networks, which embodies the private principles of cyber informatics. In this paper, we discuss the methodology to construct IPv6 networks for small organizations.
The Server Development Framework Based on the Completion Port
Authors: Yu Jun Xi , Lou Guo Huan
Published: August 2013

The network service applications based on socket have been widely used, however it is still difficult to realize network service application program with a large amount of data and connections. This paper describes the principle of completion port, and based on this, analyses and introduces the various steps to achieve completion port and describes the usage of key functions in detail. Finally the client and server are simulated for the testing. The results show based on the I/O completion port technology the server application can get a good expansibility.
The Study of Server Load Scheduling Strategy
Authors: Yu Jun Xi , Lou Guo Huan
Published: August 2013

In this paper the classification and development of server load balancing technology are briefly described and the load balancing algorithms based on server cluster are compared. A server load balancing technology and algorithm based on multiple parameters are proposed. Finally, the load balancing algorithm is tested. Testing results show that the method is feasible.
Campus Network Based on VRRP Redundancy and Reliability
Authors: Yin Xiao Qi , Guo Yi Zhuo
Published: August 2013

With the dramatic increase in amount of information in campus network, the security and high reliability of access data have become urgent requirements on redundancy reliability design of campus network. This paper adopts the technology of VRRP and takes advantages of double backup sets and router to process the design and configuration. As is shown in the experiment, when one device fails, the other ones can still complete relevant operations under the conditions of double backup sets. Therefore, the redundancy reliability design of campus network can be realized through the technology of VRRP double backup sets.
A Hierarchical QoS Routing Protocol for the Wireless Sensor Networks
Authors: Zhou Ze Sshun , Xu Yi , Qin Min , Mao Chu Yang , Li La Yuan
Published: August 2013

The large wireless sensor networks are often structured hierarchically by grouping nodes into different domains in order to deal with the scaling problem. This paper proposes a new protocol called hierarchical QoS routing protocol (HQRP) that achieves scalability by organizing the network as a hierarchy of domains using the full-mesh aggregation technique. In HQRP, each local node just only needs to maintain local routing and summary information of other domains, but does not requires any global states maintained. The HQRP uses a Reverse Best Metric Path Forwarding approach with hierarchical, topological and QoS forwarding conditions to construct the multicast tree while minimizing message overhead and satisfying delay-bandwidth and minimum energy consumption. The paper presents proof of correctness and complexity analysis of the HQRP. Simulation results show very good performance in terms of success ratio and message overhead.
On the Research of Adaptive Frequency Hopping in the Wireless Communication
Authors: Liang Xiao Hu , Cheng Lei
Published: August 2013

The multipath fading and interference problems in the wireless communication lead to the link quality decrease severely. However, the conventional frequency hopping scheme cannot solve the problems in an effective way. Adaptive frequency hopping scheme, which is based on the automatically link quality analysis, can avoid the bad frequencies and guarantee the desired level of channel quality. The system is analyzed based on the adaptive frequency hopping model equipped with link quality analyzer which is different from the traditional one. In the paper, some newly proposed adaptive frequency hopping schemes have been summarized, which provide an important reference for the practical application.
Comparative Analysis of Mobile Ad Hoc Network Routing Protocols Simulation
Authors: Wei Xiao Yan
Published: August 2013

A Mobile Ad Hoc Network (MANET) is a popular research topic. In this paper, we first describe characteristics of MANET, proactive and reactive routing protocols. Then AODV and DSDV, which are widely investigated in Ad Hoc network are introduced. We use simulation tool NS-2 to design three experiments to evaluate AODV and DSDV based on measure such as the packet drop rate, delays and average throughout. According to experimental results, conclusions and improvement suggestions are given to help further develop and optimize routing protocols.
Multiple Constrained QoS Routing Algorithm Based on Genetic Algorithm in Overlay Network
Authors: Ge Jun Wei , Deng Jin Xin , Fang Yi Qiu
Published: August 2013

How to depend on different services provide different guarantee of QoS, and to ensure the effective use of network resources will become an important task in overlay network. In this paper, we consider constraints of network bandwidth, delay, loss rate, cost ,and base on the resources of current global network, as well as user-specific QoS metric needs to choose the best QoS route based on genetic algorithm. Experiments show that the algorithm is feasible in overlay network routing,and it has the better global load balancing capabilities.
A Novel Network Survivability Analysis and Evaluation Model
Authors: Wang Chun Lei , Wang Dong Xia , Miao Qing , Ming Liang , Fang Lan , Dai Yi Qi
Published: August 2013

Network survivability has the characteristics of complexity, dynamic evolution and uncertainty, which has become one of the most important factors for analyzing and evaluating network performance. Network survivability analysis and evaluation is a process of analyzing and quantifying the degree to which network system can survive in network threats. This paper proposes a novel network survivability analysis and evaluation model.Firstly, network survivability is abstracted as a dynamic game process among network attacker, network defender and normal user, thereafter network survivability evolutionary game model is established and network survivability analysis algorithm is proposed based on the game model. Secondly, the survivability characteristics of the network can be measured and evaluated based on the analyzed information based on the proposed immune evolutionary algorithm for network survivability metric weight solving and network survivability evaluation method using multiple criteria decision making. Finally, the proposed network survivability analysis and evaluation model is experimented in a typical network environment and the correctness and effectiveness of the model is validated through experimental analysis.
Design of a Static Test System of Photoelectric Parameters for a Smart Ammunition
Authors: Zhang Wan Fa , Chen Lei , Shan Ti Qiang
Published: August 2013

A static test system of photoelectric parameters for a smart ammunition is introduced, which provides a new solution for the detection of smart ammunitions. The system uses the technology of virtual instruments, PXI buses and intelligent connectors, constructs its hardware platform by the method of PXI modules, develops the test software in the circumstance of LabWindows/CVI and accomplishes the test of related parameters by the control of relevant modules. Experiments show that, the system designs reasonably, compared with traditional testing instruments, it is more accurate, reliable, and has favorable extending. It can also finish many other kinds of smart ammunitions by add or reduce relevant hardware modules and software modules.
A Scheme of HARQ Resending Nodes Selection in RCC Network
Authors: Li Xue Hua , Li Zhen Song , Wang Ya Fei
Published: August 2013

A scheme of HARQ re-sending nodes selection for relay network is purposed in this paper. The study is focused on how to select relay node with minimum resending power under the particular required receiving performance of the destination node. The candidate relay nodes are divided into several regions according to the difference of resending power required. With this selection scheme, the diversity gain and high system power efficiency can all be achieved. The effectiveness of this scheme is proved by the simulation results.
Research of Application of FCE to Project Supervision
Authors: Liu Yan
Published: August 2013

Construct the fuzzy comprehensive evaluation model on geological exploration project supervision index system, and be able to provide reference for geological and mineral exploration relating departments to make decisions. The comprehensive evaluation model is proven to be effective by analyzing some index selection solutions. Apply fuzzy comprehensive evaluation (FCE) method to the selection of geological exploration project supervision indexes, analyze the weights of the various factors which affect the indexes first, then perform fuzzy comprehensive evaluating on the indexes to be determined, and finally classify the evaluated objects and select corresponding indexes according to evaluation results. The method resolves the issues of strong subjectivity and results lacking of quantization which are caused by selecting indexes by simple analogy, and has higher scientificity and practical values.