Volume 37,Issue 6,2014 Table of Contents

1 Neutral point grounding mode decision algorithm for medium voltage distribution network

XIONG Xiaofu , LIU Hengyong , OUYANG Jinxin , GONG Xiufen , XIE Yinghua , LI Jing

2014, 37(6):1-9. DOI: 10.11835/j.issn.1000-582X.2014.06.001

[Abstract](1062) [HTML](422) [PDF 7.74 M](986)

Abstract:
Different neutral point grounding modes have their own advantages and disadvantages，and the decision making of neutral point grounding mode for medium voltage distribution network needs to consider the power supply reliability，overvoltage and insulation coordination，relay protection，communication system interference，electrical safety and grounding device，which relate to the electric network reliability，security and economy movement aspect.A neutral point grounding mode decision method which comprehensively considers the reliability，safety and economy factors is proposed.The method combines the reliability evaluation，safety protection，construction and operation cost with the realization of distribution network for different neutral point grounding modes，and makes the optimal decision of neutral point grounding mode by calculating life cycle cost of different neutral grounding modes and coordinating the reliability index.An example is used to verify the feasibility and effectiveness of the decision method.

2 Learning in memristive neural networks with various connection patterns

LI Chuandong , TIAN Yuan , CHEN Ling , GE Junhui

2014, 37(6):10-16. DOI: 10.11835/j.issn.1000-582X.2014.06.002

[Abstract](1334) [HTML](806) [PDF 8.07 M](1278)

Abstract:
Due to the useful properties of nonvolatile，memory and nanoscale，memristors have prospective promising applications in artificial networks，pattern recognition and signal processing.This paper exploits the learning rule of the memristive network based on spiking timing dependent plasticity (STDP) and uses the genetic algorithms with self-adaptation and variable topologies，which allows the number of hidden neurons，connection weights，and connectivity pattern to change self-adaptably.Three memristor models are respectively used as the synapse in the network，including HP linear memristor，non-linear memristor and threshold memristor.The comparison of the performance of the three memristive neural networks is presented，and the hybrid memristive networks’ learning effects are analyzed.

3 Lateral unloading true triaxial test and analysis of mechanical properties for red clay

ZHOU Yuanzhong , LIU Xinrong , YU Yu , DAI Ziran

2014, 37(6):17-24. DOI: 10.11835/j.issn.1000-582X.2014.06.003

[Abstract](1114) [HTML](397) [PDF 8.61 M](881)

Abstract:
The actual excavation process of the deep foundation pit is simulated by single sided lateral unloading true triaxial test by using rigid-flexible compound true triaxial apparatus.The stress-strain relation，breakage process and change characteristics of the soil strength parameters are analyzed under lateral unloading and vertical loading conditions during the excavation of the pit.Then the reduction factor is determined according to the change characteristics of the red clay strength parameters during the excavation and experience in engineering practice.The soil strength parameters are reduced with double strength reduction methods step by step.The mechanical process for the excavation of the red clay pit is simulated by using FLAC 3D procedures and Mohr-Coulomb model.The results show that the mechanical mechanism of the deformation and breakage process for red clay under lateral unloading condition is completely different from that of vertical loading.Soil strength parameters decrease while the depth of the excavation increases and the changes in range，magnitude and speed are changed incrementally.In the same vertical load condition，the soil under excavation condition is more deformable and easy to breakage compared to that under pressure conditions，which leads to the instability.

4 Mechanical characteristics of tied-arch bridge under structural defects and traffic increase

ZHAO Hu , PU Qianhui

2014, 37(6):25-32. DOI: 10.11835/j.issn.1000-582X.2014.06.004

[Abstract](1012) [HTML](377) [PDF 6.97 M](1012)

Abstract:
To study the mechanical performance of tied-arch bridge under structural defects and traffic increase，a limited element model of Panzhihua Luoguo Jinshajiang Bridge is established and analyzed.Firstly，common damage models and their influence factors are presented.Then，based on established engineering model，changes of suspender force caused by arch rib lineation defect，hanger lineation defect and boom failure are calculated and analyzed respectively.Calculation results show that，suspender forces are more sensitive to arch’s vertical defect than to its transverse defect.While，short hangers are more sensitive to lineation defect than long ones，and secondary moment and shear force in short ones are bigger than in long ones.The results also tells that single boom failure can fiercely change neighbor booms’ forces，at the same time，boom failure spreads faster in short boom area than in long boom area.Traffic increase accelerates structure’s fatigue fracture.

5 MicroRNA and transcription factor regulatory network

XIONG Lili , ZHANG Bao , GUO Zhiyun

2014, 37(6):33-37. DOI: 10.11835/j.issn.1000-582X.2014.06.005

[Abstract](2619) [HTML](928) [PDF 4.39 M](1179)

Abstract:
MicroRNAs (miRNAs) are a class of short non-coding RNAs of 18 to 24 nucleotides in length that post-transcriptionally regulate various target genes which involving in a variety of biological processes such as cell cycle，differentiation，cell proliferation，and apoptosis.At the transcriptional level，transcription factors (TFs) has been considered as the primary regulator to control the gene expression.Recent studies show that transcription factors regulate the expression of miRNA，and participate in a variety of biological processes including tumorigenesis.The regulatory network of TF-miRNA has been studied widely，and this paper reviews the recent research findings.It’s hoped to provide a theoretical basis for study of regulatory pathway of TF-miRNA in the future.

6 Shaking table test and finite element analysis of seismic response in reinforced asphalt isolation pier

SHANG Shouping , ZHOU Hao

2014, 37(6):38-44. DOI: 10.11835/j.issn.1000-582X.2014.06.006

[Abstract](1242) [HTML](617) [PDF 7.73 M](1079)

Abstract:
Sinusoidal excitation shaking table test of full-scale reinforced asphalt isolation pier masonry building is carried out，and ANSYS is applied to set appropriate space finite element model，and then numerical simulation is given to the isolation pier.Comparison of both results of numerical simulation and shaking table test indicates that they agree well with each other.The result shows the applicability of finite element in reinforced asphalt isolation pier analysis.Seismic response analysis is given to the isolation and non-isolation model，and the result shows displacement of isolation layer is increased with the increase of input amplitude under same seismic excitation.The acceleration amplitude at the top of structure and story displacement of isolation model is less than that of non-isolation model，which indicates that the isolation layer has an excellent performance under seismic action，and it reduces the shear force of upper structure.

7 LDPC encoding and decoding design based on Verilog HDL

HE Wei , GUO Zhihuan

2014, 37(6):45-50. DOI: 10.11835/j.issn.1000-582X.2014.06.007

[Abstract](1852) [HTML](1146) [PDF 5.91 M](1205)

Abstract:
LDPC (low density parity check code) is one of the most excellent codes，and it is a strong competitor of the fourth generation communication system (4G) as its performance is close to Shannon transmission limit.The paper realizes LDPC encoding and decoding algorithm through Verilog to improve computational efficiency，and selects π rotation matrix construction method to encode.And queen algorithm avoids the appearance of Cyclotella in H matrix.The UMP BP-based algorithm is also used in decoding and all of decimal fractions are limited between -100 and 100.For a large number of decimal fractions，the Q8 (fixed-point) format is adopted to express them and the range is between -128 and 127.996 093 75 with the precision of 0.003 906 25.Thus floating-point arithmetic can be avoided and Verilog language can be used to describe the LDPC decoding algorithm.The program does not use any IP core，which means it can be applied to all FPGAs and has good transplantation.It has high application value in engineering.

8 Geothermal heat power organic Rankine cycle system under different condensation temperatures

MIAO Zheng , LIU Guanglin , XU Jinliang , LV Pengfei , ZHANG Bing

2014, 37(6):51-55. DOI: 10.11835/j.issn.1000-582X.2014.06.008

[Abstract](1204) [HTML](499) [PDF 4.76 M](1065)

Abstract:
In the geothermal heat organic Rankine cycle power generation system，condensation temperature is sensitive to the environment condition while the geothermal fluid parameters remain constant.In this paper simulation of the ORC system is carried out through the EES software to analyze the effect of the condensation temperature in a saturated organic Rankine cycle power generation system using R245fa and R601a as working fluid.The optimal expansion ratio，mass flow rates and the inlet temperature of the expander are also studied.The results show that，when the temperature of the geothermal fluid is kept at 130 ℃，the optimal working fluid temperature at the expander entrance increases by 15 ℃ with the condensation temperature decreasing from 30 ℃ to 0 ℃.At the same time，the system net power output growth by 120%，refrigerant mass flow rate increases more than 30%，and the expansion ratio becomes approximately 2 times higher.This leads to higher requirements on the initial system design and control.

9 FPGA optimal implementation of AES based on Verilog HDL

LI Lang , ZOU Yi , LI Renfa , LI Kenli

2014, 37(6):56-64. DOI: 10.11835/j.issn.1000-582X.2014.06.009

[Abstract](1759) [HTML](1044) [PDF 9.91 M](1720)

Abstract:
AES algorithm is a widely used cryptographic algorithm.To improve AES algorithm，it’s proposed to repeatedly call key expansion module to realize efficient use of the code.Ten-round keys are generated at the same time，and operations of add round key are achieved by the control module.The key is called repeatedly when the AES algorithm is running for encryption and decryption.The realization of AES is verified by modelsim6.1f.AES algorithm is designed with Verilog HDL，and a clear description about the critical core code realization of the process is proposed.The hardware implementation is verified by FPGA.Experimental results show that the optimized AES algorithm has only 3 531 slices，5 522 LUTs on a Xilinx Virtex-V FPGA.Our implementation occupies less area and it can get the same performance with comparing with other implementations of the AES，so it can meet application requirements of smaller chip，which can make the AES algorithm be applied to the popular small area on the smart card.It can make the AES algorithm use in the smart card.

10 An image encryption and compression algorithm based on chaos system and wavelet transform

CHEN Hong , BAI Sen , LIU Bowen

2014, 37(6):65-70. DOI: 10.11835/j.issn.1000-582X.2014.06.010

[Abstract](1308) [HTML](576) [PDF 5.75 M](1081)

Abstract:
An image encryption and compression algorithm based on chaos system and discrete wavelet transform (DWT) is studied in this paper.Firstly，four original secret images are transformed by DWT，and then the four low-frequency components are used to compose a two-dimensional coefficient matrix.The matrix is scrambled and encrypted by the chaos system，and then encrypted coefficient matrix is decomposed into four two-dimensional coefficient matrixes.Finally，an encrypted compressed image is obtained by the inverse DWT using the four decomposed two-dimensional coefficient matrices.Encryption and compression are realized at the same time in this algorithm which realizes the combination of chaos and wavelet transform，the experimental simulation and analysis show that the algorithm has good encryption and compression performance.

11 Max-relevance min-redundancy restrictive BAN classifier learning algorithm

FENG Yuejin , ZHANG Fengbin

2014, 37(6):71-77. DOI: 10.11835/j.issn.1000-582X.2014.06.011

[Abstract](1226) [HTML](338) [PDF 5.34 M](1154)

Abstract:
NB (Naive Bayes) classifier is a simple and effective classification method，which is based on Bayes theorem.However，its attribute conditional independence assumption usually doesn’t correspond to reality，which affects its classification performance.BAN (Bayesian network Augmented Naive Bayes) classifier extends the ability to represent the dependence among attributes.However，BAN learning algorithms need a large amount of high dimensional computations，which impairs the classification accuracy of BAN，especially on small sample datasets.Based on the variant of max-relevance min-redundancy feature selection technology，a new restrictive BAN classifier learning algorithm (k-BAN)，which builds the dependence by selecting the set of edges for each attribute node，is proposed.Compared with NB，TAN and BAN classifiers by an experiment，the restrictive BAN classifier of our algorithm has better classification accuracy，especially on small sample datasets.

12 A design method of embedded visual access control system

QIU Shaojian , JIANG Siyu , LIU Aishi , YANG Jian , HUANG Churan

2014, 37(6):78-82. DOI: 10.11835/j.issn.1000-582X.2014.06.012

[Abstract](1495) [HTML](365) [PDF 5.84 M](1518)

Abstract:
As the demand of home security is increasingly， we propose a program which based on wireless door access control system and describe the composition and overall scheme of the system. Outdoor machine which equips infrared camera communication with indoor center via wireless network. The indoor center applies ARM11 processor， and Android operating system to manage various application processes. Software and hardware design methods of indoor center are introduced in details，and outdoor machine and indoor center are manufactured for testing. Results show that the system is stable， has achieved the desired objects，can meet the needs of uses， and result demonstrates the feasibility of the design.

13 An improved FCM algorithm and its application to EEG signal processing

YU Wei , WAN Daili , YANG Xijing , ZHOU Ya

2014, 37(6):83-89. DOI: 10.11835/j.issn.1000-582X.2014.06.013

[Abstract](1253) [HTML](436) [PDF 6.19 M](1176)

Abstract:
Most of the popular EEG classifiers need to be supervised and their parameters have to be trained by a number of train data in advance.That’s the reason why they cannot be used in the real-time circumstances.In this paper，a new FCM unsupervised classification algorithm is proposed which is based on the density size of data dot and mahalanobis distance.Then，the algorithm is used to classify the EEG signals from the database of the second session of 2003 BCI competition.The EMD algorithm is used to decompose the EEG and extract the characteristic values，and then these values are classified by the proposed FCM algorithm.The experimental results show the algorithm’s feasibility and validity in the EEG classification field.

14 Repeated game theory intrusion detection model for the Internet of Things

ZUO Jun

2014, 37(6):90-96. DOI: 10.11835/j.issn.1000-582X.2014.06.014

[Abstract](1537) [HTML](744) [PDF 6.25 M](1095)

Abstract:
The existing security methods cannot be applied to the Internet of Things due to the defects of communication nodes. To solve this problem, an intrusion detection model based on repeated game theory is presented. A repeated game model algorithm for detecting malicious nodes is built, and the algorithm of Quantal Response Equilibrium (QRE) is used for optimizing the model and making results reach the Nash equilibrium. Moreover, a common punishment strategy is introduced to improve the success of transfer data in this model. The results of the simulation represent that this model can restrain malicious nodes attacking effectively and improve the efficiency of network.

15 Decouple control for symmetrical six-phase PMSM series-connects three-phase PMSM system based on harmonics couple

LIU Lingshun , ZHAO Guorong , HAN Haopeng

2014, 37(6):97-103. DOI: 10.11835/j.issn.1000-582X.2014.06.015

[Abstract](1437) [HTML](288) [PDF 7.77 M](1228)

Abstract:
Symmetrical six-phase series-connected three-phase PMSM driven by single inverter is a novel multi-machines system. To research EMF harmonics influence on the decouple control of series-connected system, the series-connected system mathematic models with 2nd harmonic of symmetrical six-phase PMSM under d-q coordinates are deduced. The torque ripple amplitude and frequency influenced by harmonic are discussed. The decouple control strategy based on harmonic effect compensating is presented. And the simulations with variable operating states are proposed to validate the feasibility.

16 Distribution of trust model in P2P network based on equilibrium theory

WANG Huadong , LIAO Li

2014, 37(6):104-111. DOI: 10.11835/j.issn.1000-582X.2014.06.016

[Abstract](1080) [HTML](885) [PDF 8.50 M](1067)

Abstract:
There are a large number of malicious attack nodes and collusion groups in P2P(peer to peer) network, and the existing trust models improve the P2P network environment to some extent, but the emphasis of the models are different, which are unable to fully solve large-scale malicious attacks and deception. Therefore, a P2P trust model based on equilibrium theory is presented. The model consists of the construction of the trust structure, the malicious node detection and trust speculation. It constructs trust network according to the equilibrium theory, uses the equilibrium theory to define nodes balance factor, detects balance malicious nodes by calculating the impact of malicious behavior on the network, and adopts trust inference algorithm to estimate trust nodes to prevent distrust network nodes being added. Experimental results show that the model is reliable, and the algorithm is efficient and robust.

17 Application of ultrasonic detection for partial discharge to cable terminals

ZHAO Aihua , LI Wei , YE Jiantao , DING Guocheng

2014, 37(6):112-118. DOI: 10.11835/j.issn.1000-582X.2014.06.017

[Abstract](1269) [HTML](664) [PDF 6.02 M](1076)

Abstract:
This paper studies the influence of the discharge point depth on the ultrasonic detection results of partial discharge in cable terminals to find an effective method to analyze discharge position and discharge level according to the results of cable terminal discharge ultrasonic signal field test. With ultrasonic wave propagation and attenuation theory, this paper analyzes the tangential and longitudinal distribution pattern of discharge signals in cable terminal surface and puts forward a calculation method about the true depth and discharge level of partial discharge source on the cable terminal by the way of theory analysis, simulated calculation, laboratory test and field application. The result reveals that the detected ultrasonic signal level decreases as the axial distance or the central separation angle between the discharge point and the test point increases, and the depth of discharge point influences the change rate of the detected ultrasonic signal level along with the axial distance and the central separation angle. The lower depth means the larger change rate and the higher depth means the less change rate. It’s also revealed that the measured discharge point depth and discharge level by the proposed iteration method are consistent with real situation.

18 Analysis of temperature field around groundwater heat source wells under coupled thermal conduction and groundwater advection conductions

XI Peisheng , WANG Xing

2014, 37(6):119-124. DOI: 10.11835/j.issn.1000-582X.2014.06.018

[Abstract](1021) [HTML](452) [PDF 7.91 M](1029)

Abstract:
For studying the effect of the groundwater heat source wells working on the temperature field，the Comsol Multiphysics is used to build a three dimensional numerical model which couples thermal conduction and groundwater advection conductions. Some conclusions have been concluded by contrasting five different conditions that under different quantities of heat exchanged water put into the recharge well and a detail analysis of one. With the quantity of recharged heat exchanged water becoming larger, the influence radius expands and the heat surface between the two wells transfers more quickly to the pumping well. Temperature of the region close to the recharge areal increases obviously in early stage，while temperature of the region not so close to the recharge area ismore influenced in later stage. The temperature is closely relate to the seepage velocity and has nothing to do with position. Influence radius is almost proportional to seepage velocity.

Home

Volume 37,Issue 6,2014 Table of Contents

Current Issue

Volume

Issue

Most Read

Most Cited

Most Downloaded