Table of Content

20 February 2005 Volume 32 Issue 1

  

Original Articles

A new multiple description video communication scheme and layered algorithm for an ad hoc network

ZHANG Fang;WANG Yangli;XIAO Song

J4. 2005, 32(1):  1-6. 

Abstract ( 1299 )   Save

Related Articles | Metrics

A new multiple description video coding system for wireless ad hoc networks is proposed. When fast motion of
video contents is detected, a reference frame will be inserted into the descript
ion selection array adaptively in the proposed scheme, which improves the coding
efficiency of motion estimation and protects the bit stream from error propagat
ion. The multiple description layered coding method based on the proposed adapti
ve reference insertion (called ARIMDLC) is described in detail, which generate
s the base layer and enhancement layers for each description, making the video b
it stream more robust and suitable to the drastic network bandwidth fluctuation.
According to the characteristics of the ad hoc multihop network, a multipat
h transmitting strategy is designed for the ARIMDLC data packets, and three st
ates Markov process is used to model the wireless channel. Simulation results sh
ow that the proposed scheme can obviously improve the performance and offer an a
verage gain of 1.6dB in PSNR.

Design of transmitting waveforms and its demodulation in the coast-ship multi-static ground wave over-the-horizon radar

CHEN Bo-xiao;MENG Jia-mei;ZHANG Shou-hong

J4. 2005, 32(1):  7-11. 

Abstract ( 1718 )   Save

Related Articles | Metrics

For the coast-ship multi-static ground wave over-the-horizon radar, multiple carrier-frequency signals a
re radiated simultaneously with multiple antennas in its transmitting station, and a “broadcasting” transmitting way is formed. The principles for the design of its transmitting waveforms are presented. Frequency modulated interrupt conti
nuous wave (FMICW) waveforms are adopted in this radar. The relationships of waveform parameters with range resolution, maximum unambiguous range, Dopple walk, and so on are discussed. The receiver station is on the ship and samples of tran
smitted waveforms cannot be received directly, so the conventional analog mixer cannot be used and the method of full digital demodulation of transmitted waveforms in the receiver station is presented. Simulation results show that the waveforms designed are effective.

Numerov algorithm for tunneling

LI Cun-zhi(1);LIN Xiao-chun(2)

J4. 2005, 32(1):  12-15. 

Abstract ( 1440 )   Save

Related Articles | Metrics

A new approach to calculating
electron tunneling, which can be applied to the one-dimensional potential barr
ier with an arbitrary profile, is presented. In the approach, the electron trans
mission coefficient is obtained from the solution of the Schrodinger equation wh
ich can be numerically solved with the Numerov algorithm. In order to test the a
ccuracy of the algorithm, the transmission coefficients of the electron tunnelin
g through a double-barrier and a triangular barrier are calculated respectively
. A comparison of numerical results with corresponding analytical values shows t
hat this approach is of very high accuracy.

A novel method for video error concealment based on watermark

YANG Fu-zheng(1);CHANG Yi-lin(1);WANG Xin-dai(1);WANG Jing(2)

J4. 2005, 32(1):  16-20. 

Abstract ( 1775 )   Save

Related Articles | Metrics

A novel method for video erro
r concealment based on watermark is proposed. By utilizing the feature of digita
l watermark, the information on motion vectors is hidden in DCT coefficients at
the video coder. Then, error detection and error concealment are performed using
motion vector information extracted from DCT coefficients at the video decoder.
Simulation results demonstrate that the accuracy of video error detection is im
proved significantly by our method, and the average PSNR of the reconstructed vi
deo is 2～3dB higher than that of other existing techniques under the environm
ent of an error bit rate less than 10^-3.

Fast algorithm for real time SAR imaging on a parallel processor

SU Tao;ZHUANG De-jing;WU Shun-jun

J4. 2005, 32(1):  21-25. 

Abstract ( 1522 )   Save

Related Articles | Metrics

A novel fast algorithm for re
al time SAR imaging is presented to decrease the volume of compression computati
on. For any size sequence, a scheme and procedure for zero-padding-decompositi
on FFT are proposed and optimized to minimize computation operations. This algor
ithm lowers the computational volume of zero padding FFT in SAR imaging, improve
s the performance of real time SAR imaging on a parallel processor, increases th
e throughput and decreases the imaging delay.

Performance analysis of a novel multiple access algorithm for the wireless LAN

HE Hong;LI Jian-dong;SHENG Min;LI Wei-ying

J4. 2005, 32(1):  26-303. 

Abstract ( 1179 )   Save

Related Articles | Metrics

This paper presents a novel a
lgorithm, called Enhanced Distributed Contention Control, for improving the perf
ormance of DCF(Distributed Coordination Function) Operations of IEEE 802.11 Wir
eless LAN(WLAN). The EDCC algorithm is an extension of the existing DCC algorith
m by applying a more precise scheme for estimation of the values of slot utiliza
tion and contention degree. The Enhanced DCC algorithm reduces the distortion of
estimating slot utilization by using an ARMA Filter method to utilize the succe
ssive estimating value of slot utilization compared with the DCC algorithm avail
able. At the same time, the EDCC algorithm keeps the main characteristics: simpl
icity, integrability, complete distribution, Absence of overheads, and adaptiven
ess. Results show that the EDCC algorithm can provide higher channel utilization
and lower network load compared with the DCC algorithm existing.

A new method for frequency estimation from wide-band under-sampled data

WANG Hong-yang;ZENG Cao;LIAO Gui-sheng

J4. 2005, 32(1):  31-35. 

Abstract ( 1508 )   Save

Related Articles | Metrics

A new method for estimating t
he frequency from wide-band under-sampled data is proposed. With the aid of al
iased frequency information from two independent sampling channels and the propo
sed pairing method, we can solve the frequency ambiguity. Furthermore, the propo
sed method is not sensitive to the amplitude and phase errors of both channels a
nd data obtained from two channels can be processed separately, and thus it has
a wider applied field than the existing methods. The high estimation accuracy of
this proposed algorithm is confirmed by comparing simulation results with CRLB
accomplished at the end of this paper.

A hierarchical multiresolution video shot transition detection method based on the integer-to-integer wavelet

HAN Bing;JI Hong-bing;GAO Xin-bo

J4. 2005, 32(1):  36-40. 

Abstract ( 1564 )   Save

Related Articles | Metrics

A detection method for the sh
ot boundary detection is proposed based on the integer-to-integer wavelet, and
hierarchical multiresolution. The dissimilarity function is presented by using
wavelet coefficients directly combined with the norms theory, and according to t
he problem of threshold determination difficulty and the feature of confusing gr
adua
l transition with motion easily, the automatic threshold selection method and th
e scheme of twice search by the Tschebyscheff distance are presented. Integer-t
o-integer WT has advantages in speed over the first generation WT and adaptatio
n to dealing with an amount of video data. This method can overcome flash and mo
tion effects efficiently. The experimental results with real video clips demonst
rate that a trade-off between recall and precision is up to more than 98% and
90% no matter what abrupt transitions or the gradual transitions.

Study of “snap back” of the atomic force microscopy

TIAN Wen-chao;JIA Jian-yuan

J4. 2005, 32(1):  41-43. 

Abstract ( 1351 )   Save

Related Articles | Metrics

“Snap back” affects the cap
ability of the Atomic Force Microscope(AFM). On the basis of the Hamaker micro c
ontinuous medium theory, the adhesion mathematic model between the tip and the s
ample of the AFM is set up, which includes the repulsive force. The relationship
between the plastic force of the cantilever and the adhesion of the AFM is disc
ussed. The reason for the AFM “snap back” is discovered. By improving the rigi
dity of the cantilever, a method for avoiding “snap back” is put forward, foll
owed by the simulation result.

Design and transmission characteristics simulation in MCM placement and routing

CHANG Yi-feng;YANG Yin-tang;CHAI Chang-chun

J4. 2005, 32(1):  44-47. 

Abstract ( 1336 )   Save

Related Articles | Metrics

In the high speed multichip m
odule(MCM) design, signal integrity is pivotal. By means of a real fault-detect
or example, the paper gives an improved method for MCM placement and routing. Th
e analysis results of signal characteristics, such as reflection, delay and elec
tromagnetic interference, in both time domain and frequency domain, are discusse
d to optimize the circuit structure in the design process. Here we adopt 50M
Hz pulse signal as the trigger and utilize Spectra Quest software as the simul
ation tool. The simulation results show that the noise margin is up 124. 86m
V; the high overshoot and low down 180. 61mV, 465. 36mV respective
ly; the propagation delay, switch delay and settle delay down 0. 407835ns
, 0. 4188ns, 0. 35968ns respectively; the relative delay of in
put signals is not longer than 0. 2ns and the intensity of electromagnetic
interference is decreased 10% and above. The results above indicate that the a
djusted and optimized placement and routing design can meet the signal transmiss
ion requirements.

Blind space-time multiuser detector based on U-D factor filter

XUE Yi-bing;LI Jian-dong

J4. 2005, 32(1):  48-516. 

Abstract ( 2008 )   Save

Related Articles | Metrics

As a method for eliminating m
ultiple access interference (MAI) in CDMA, blind space-time multiuser detection
based on the Kalman filter will face the problem of numeric stability when used
in 16bits or 32bits microprocessor or DSP. So a high performance blind spac
e-time multiuser detection algorithm is proposed by introducing the U-D factor
Kalman filter to estimate the optimal decision vector of the CDMA multiple-use
r
s receiver. This algorithm can converge rapidly, track in high accuracy and has
satisfied numeric stability. Simulation results show that this algorithm can eli
minate multiple access interference (MAI) efficiently and is robust to numerical
calculation.

On mudulation classification and demodulation of MFSK signals

LUO Ming;YANG Shao-quan

J4. 2005, 32(1):  52-55. 

Abstract ( 1831 )   Save

Related Articles | Metrics

A new algorithm is proposed f
or classification and demodulation of MFSK signals. The ridge of time-frequency
representation of MFSK signals is analyzed. Modulation classification is realiz
ed by using the unsupervised clustering algorithm to determine the optimal numbe
r of clusters. In order to demodulate MFSK signals, the Haar wavelet transform i
s used to estimate the code-width and the centers of optimal clusters are used
to determine thresholds. Theoretical analysis and practical signal processing re
sults justify the robusticity and the efficiency of the new classification and d
emodulation algorithm.

Copper interconnection technology and process reliabilities in VLSI

DU Ming;HAO Yue

J4. 2005, 32(1):  56-59. 

Abstract ( 1460 )   Save

Related Articles | Metrics

New requirements are presente
d to interconnection integration technology because of the decreasing feature di
mension in VLSI devices. As a new interconnecting material, Cu can reduce the de
la
y of interconnection effectively and improve interconnecting performance. In thi
s paper, the Damascene Cu interconnecting integration technology, low-k die
lectric materials and barrier materials in Cu interconnecting integration techno
logy are introduced. It is believed that the barrier ability and reliability of
Cu interconnecting technology can be highly improved when the angle of via is 20
° and the barrier material is Ta.

Line Snake and its application in building extraction

TANG Liang(1);XIE Wei-xin(2);HUANG Jian-jun(2);XIE Xing-can(1)

J4. 2005, 32(1):  60-65. 

Abstract ( 1384 )   Save

Related Articles | Metrics

Based on line detection, we i
ntroduce a line snake algorithm with vertices of traditional snakes replaced by
straight line exemplars. Through the preliminary organization and interpretation
functions of middle-level image processing techniques (e.g., line detection) f
or the chaotic low-level image information, the proposed method reduces the com
putational, reinforces the stability and robustness of snakes, and achieves a fa
vorable performance in building extraction from aerial images.

An extended Petri net and its application

LI Zhi-wu;ZHU Rong-ming;CHEN Long-tan

J4. 2005, 32(1):  66-70. 

Abstract ( 1586 )   Save

Related Articles | Metrics

A novel calss of Petri nets,
or CDPN-Control and Data Petri Net as we call it, is developed for the modeling
, analysis, and control purposes in discrete event sytems. The formal definition
and firing rules are proposed. Meanwhile, the modeling procedure of CDPN underl
ying industrial computers and programmable logic controllers is presented. A for
mal analysis is made for the design of controls of discrete event systems. Fina
lly, an engineering example, which is an automatic carbarn, is used to illustrat
e the modeling and analysis methods of CDPN.

Global set of solutions for two types of systems of nonlinear equations in mechanical engineering

LI Tuan-jie;JIA Jian-yuan;HU Xue-mei

J4. 2005, 32(1):  71-74. 

Abstract ( 1446 )   Save

Related Articles | Metrics

This paper discusses how to f
ind the global set of solutions to two types of systems of nonlinear equations f
requently encountered in mechanical engineering. One type is the system of nonli
near polynomial equations, and a numerical approach using the homotopy method is
presented to work out all the complex or real solutions to the polynomial syste
ms without initial value selection. The other type is the system of transcendent
al equations with trigonometric functions, and a numerical method based on Newto
n’s iterative method is proposed, which can find all the real roots of the syst
em of transcendental equations with trigonometric functions without initial valu
e selection in the specified intervals. Numerical examples are given to confirm
the validity of the numerical methods. The presented methods are ultraconvenient
because there is no initial value selection in the root-finding procedure and
can easily be implemented with computers.

Super-resolution estimation of the ocean surface current for the HF ground wave radar

QIANG Yong;JIAO Li-cheng;BAO Zheng

J4. 2005, 32(1):  75-79. 

Abstract ( 1772 )   Save

Related Articles | Metrics

A method for super-resolutio
n estimation of the ocean surface current for the HF ground wave radar is presen
ted based on spatial correlation of the ocean surface current being analyzed. Fi
rst, the sequences of sea echoes of each range call are separated in the frequen
cy domain, signal sources are separated near the Bragg peak in the frequency dom
ain and then special relativity between ocean surface currents is removed by the
technique of special smoothing. Finally, the method of MUSIC is used to estimat
e the DOA of the ocean surface currents in the frequency domain. Simulation resu
lts in real data show that the algorithm for super-resolution estimation of sea
echoes in effective and practical.

Pattern analysis of dual-reflector antennas under wide-angle scanning

LIU Xu-feng;LIU Shao-dong;ZHANG Fu-shun;JIAO Yong-chang

J4. 2005, 32(1):  80-83. 

Abstract ( 1884 )   Save

Related Articles | Metrics

In order to calculate the wide-angle scanning characteristics of the dual reflector antenna, a hybrid pattern analysis method for the antenna is presented. We combine the geometrical optics (GO) with the physical optics (PO) based on the Fourier-Bessel technique, and propose an effective hybrid secondary pattern analysis method. The simulated analysis results of the hybrid method are in good agreement with the results presented in the literature, which shows that the method is feasible and accurate. Finally, the hybrid method is used to analyze a side-fed offset Cassegrain(SFOC) antenna, and its radiation characteristics as well as its gain under wide-angle scanning are given. The calculated results show that the radiation patterns of the SFOC antenna have less distortion, its gain losses are small, and its sidelobe levels are better than -20dB in the wide-angle scanning region.

Radar HRRP recognition based on the kernel matching pursuit classifier

MA Jian-hua;LIU Hong-wei;BAO Zheng

J4. 2005, 32(1):  84-88. 

Abstract ( 1450 )   Save

Related Articles | Metrics

This paper discusses radar High Resolution Range Profile(HRRP) recognition. The kernel atching pursuit algorithm, a computational efficient kernel machine training algorithm, is used to design the classifier. The power spectrum of HRRP, a translation-invariant feature, is used as the feature vector for recognition. Experimental results based on measured data show that the proposed technique achieves good recognition performance and low computational complexity.

Analytical model for DC characteristics and small signal parameters of the n-channel 6H-SiC MOSFET

WANG Ping(1);YANG Yin-tang(1);YANG Yan(1);JIA Hu-jun(1);QU Han-zhang(2)

J4. 2005, 32(1):  89-93. 

Abstract ( 1706 )   Save

Related Articles | Metrics

Based on an analytical solution of the Poisson equation and iterative calculation of the surface potential, an improved physical-based analytical model which can be used in all the operation regions for the dc I-V characteristics and small signal parameters of the n-channel 6H-SiC MOSFET is proposed utilizing the charge-sheet approximation. The influences of incomplete ionization of deep-lying impurity state and the interface state charges that have an important effect on the 6H-SiC MOSFET are considered simultaneously. The simulated maximum transconductance is 54μS at a gate voltage of 1. 9V when drain bias is 0. 05V. The comparison between simulations and physical measurements shows a good agreement. The model is imple in calculation and distinct in physical mechanism, and therefore it is suitable for the design of and the research on the SiC device and circuit.

Affine transformation observation on Rijndael S-box

LIU Jing-mei(1);WEI Bao-dian(2);WANG Xin-mei(1)

J4. 2005, 32(1):  94-97. 

Abstract ( 1671 )   Save

Related Articles | Metrics

First, a proof of the equivalence is presented among the q-polynomials, matrices of order n and linear functions over finite fields. And then based on the observation that one linear function will have distinct matrix forms under different bases, a generic scheme is extended to determine the relationship between the linear functions and matrices of order n over a finite field quickly. As another important contribution, a new scheme is also designed to determine their linear relation, with the advantage of full generality over available schemes. Finaly the essential reason why the algebraic expression for the Rijndael S-box is so simple is given.

Polarimetric adaptive matched filter with the coherent radar

LIU Li-dong;WU Shun-jun;WANG Wan-lin

J4. 2005, 32(1):  98-102. 

Abstract ( 1577 )   Save

Related Articles | Metrics

A polarimetric adaptive matched filter with the coherent radar against a gaussian background is presented. Previously proposed single chanel and double channel adaptive matched filters are extended to the case of a general number of channels. The expressions of PFA for AMF a general number of chanels are derived. It is shown that the proposed dete
ctor has the const false alarm properties with respect to the covariance matrix of the clutter. We resort to simulation to analyze the performance in different polarimetric cases.

A fast convergence decoding algorithm for LDPC codes

WANG Dan;TONG Sheng;LI Ying;WANG Xin-mei

J4. 2005, 32(1):  103-107. 

Abstract ( 1622 )   Save

Related Articles | Metrics

A realization of belief propagation algorithms based on the two-way schedule and a serial concatenated decod
ing algorithm for LDPC codes based on the matrix decomposition are presented. The performance of this new algorithm is systematically analyzed via the density evolution theory. Analysis and simulation results show that the serial concatenat
ed decoding algorithm demonstrates a higher convergence speed and has as good performance as the conventional belief propagation algorithm.

Advanced ME-Skip algorithm for motion estimation

FANG Yong(1);WU Cheng-ke(1);Halidan·A(1;2)

J4. 2005, 32(1):  108-111. 

Abstract ( 1595 )   Save

Related Articles | Metrics

Based on the ME-Skip algorithm for motion estimation proposed by H.S.Kang, an advanced algorithm for motion estimation is presented. An improvement is made on the setting of matching error(measured by SAD) thresholds. There are two SAD thresholds in the new algorithm. The smaller one is used to overcome the propagation of the matching error, while
the larger one is applied to avoid the exectution of ME to the greatest degree. When the matching error based on the prediction of the motion vector is between two SAD thresholds, a search restricted in a small window is used to replace the original motion estimation. Results show that with a little increase in coding efficiency, the proposed algorithm reduces computational complxity in motion estimation by as much as 10%～20%.

A rail-to-rail operational amplifier IP core for SOC application

ZHAI Yan;YANG Yin-tang;ZHU Zhang-ming;WANG Fan

J4. 2005, 32(1):  112-115. 

Abstract ( 1733 )   Save

Related Articles | Metrics

Based on SOC application, a Rail-to-Rail operational amplifier IP core with a low-power and a high gain is
presented. The operational amplifier will be realized in the CSMC 0.6μm DPDM CMOS process. The whole circuit is simulated with the BSIM3V3 Spice model in Hspice. With a single power supply of 5V in simulation, it is shown that the Rail-to-Rail operational amplifier has an open loop gan of 107. 8dB, a phase margin of 62. 4 degrees and a unit gain bandwidth of 4.3MHz, with the static power dissipation being only 0.34mW.

On the technique of the Web server in the micro-embedded system

ZHANG Xi-min;ZHANG Jian-guo;ZHOU Li-hua

J4. 2005, 32(1):  116-121. 

Abstract ( 1512 )   Save

Related Articles | Metrics

The Micro-Embedded Web Server system has many advantages, such as low price, easy operation, easy maintenanc
e and wide application. This paper studies the technique of the Web Server in the Micro-Embedded System for its application. It presents the structure of the hardware and the software of the Micro-Embedded System and the solution in which
the Micro-Embedded System accesses the Internet. Moreover, it discusses the methods of how to simplify the TCP/IP Protocol and how to construct the web server by software in the Micro-Embedded System. Finally, it shows the design of the
Micro-Embedded Web Server by using the MSP430F139 as the core processor to access the Internet through the RTL8019AS Ethernet controller chip. It is shown that the built Micro-Embedded Web Server experimental system can be remotely monito
red and controlled through the Internet by a WWW browser.

Investigation of characteristics of MPPC for pulse signal beams based on preset grating

LI Xiao-li;SHI Shun-xiang

J4. 2005, 32(1):  122-125. 

Abstract ( 1288 )   Save

Related Articles | Metrics

A preset grating technique is put forward for slow response characteristics of the photorefractive crystal. This technique can be achieved by the preset laser independent of the signal beam. The characteristics of MPPC based on preset grating and its physical mechanism are studied experimentally. It is indicated that the response time of photorefractive MPPC based on preset grating can be reduced greatly, and hence this technique is of great practical value for the application of MPPC with a lowly repeated narrow pulse beam.

Optimization design of phase-only transverse superresolution filters

DING Hong-ping;LI Qing-hui;ZHOU Wen-yi

J4. 2005, 32(1):  126-129. 

Abstract ( 1526 )   Save

Related Articles | Metrics

Three-zone phase-only transverse superresolution filters are designed by nonlinear optimisation at the special Strehl ratio S, which is the ratio of the maximum intensity of the central core of the superresolving pattern to the Airy pattern. The design model and several examples are presnted and compared with the superresolution filters of references with better resolving effects. To suppress the strong sidelobe intensity, these phase-only filters are used in the confocal scanning microscopy system and the sidelobe can be restrained greatly.

Analysis of oblivious transfer

JIANG Zheng-tao;HAO Yan-hua;WANG Yu-min

J4. 2005, 32(1):  130-132. 

Abstract ( 1655 )   Save

Related Articles | Metrics

We analyze the security of the three m out of n oblivious transfer schemes proposed by Y.Mu et al, and then point out the insecurities of their schemes. We also provide our improvements on them respectively, which prevent users from getting more messages or disobeying the protocol. One of the improved schemes is more efficient than all the schemes proposed by Y.Mu et al.

A multi-period model combining pricing, inventory and capacity expansion

WEI Yi-hua(1);HU Qi-ying(2)

J4. 2005, 32(1):  133-138. 

Abstract ( 1472 )   Save

Related Articles | Metrics

This paper discusses the inventory, pricing and capacity strategies of a single item with periodic review. By
using the Markov Decision Process, the finite horizon inventory, pricing and capacity expansion problem is discussed, whose optimal strategy is obtained. We also discuss the problem in infinie horizon.

Normal MP-ideals of R₀-algebras

LIU Yong-lin(1;2);LIU San-yang(1)

J4. 2005, 32(1):  139-141. 

Abstract ( 1343 )   Save

Related Articles | Metrics

R₀-algebra is a class of logic algebra based on a systematic research on the formal deductive system L^*. The main aim of this paper is to investigate the structure of R₀-algebras, with the notion of normal MP-ideals in R₀-algebras introduced. The relations between normal MP-ideals and MP-ideals are given. The c
haracterization property and the extension property of normal MP-ideals are obtained. The normal R₀-algebras are completely characterized by the normal MP-ideals.

Measurement of pressure and displacement by using the optical fiber grating sensor based on the C-shaped elastic tube

ZHOU Hong;QIAO Xue-guang;WANG Hong-liang;WEI Ting;LI Lan

J4. 2005, 32(1):  142-145. 

Abstract ( 1334 )   Save

Related Articles | Metrics

The structure design of a fiber Bragg grating (FBG) sensor based on the C-shaped elastic tube has been put forward. The tuning of the FBG reflected wave length is carried out by using the excess pressure in the elastic tube for making the free end of the said tube produce displacement, or making the surface of the said tube produce stress. The linear elationship of FBG reflected wavelength variation against both the pressure and the free end displacement has been obtained. In a ressure range of 1～6MPa, the relationship between FBG reflected wave length and pressure or displacement is a linear characteristic, with the sensitivity of the pressure and displacement sensor reaching 0. 0305nm/MPa and 0. 0359nm/mm respec
tively, with the linear tuning range being 0.183nm and 0.215nm respectively, and with the wave length resolving capability being 3.05pm and 0.718pm respectively.

title

Authors

J4. 2005, 32(1):  146-151. 

Abstract ( 1246 )   Save

Related Articles | Metrics

A novel plate diaphragm based in-fiber Bragg grating sensor for simultaneous measurement of temperature and pressure

FU Hai-wei(1;2);FU Jun-mei(1);QIAO Xue-guang(2);ZHAO Da-zhuang(2);WANG Hong-liang(2);JIA Zhen-an(2)

J4. 2005, 32(1):  151-155. 

Abstract ( 1655 )   Save

Related Articles | Metrics

A novel plate diaphragm based FBG sensor is proposed to measure temperature and pressure simultaneously. Two
FBGs are attached radially and circumferentially to a metal diaphragm respectively, and when temperature and pressure change, the peak wavelength of the FBGs will shift. The peak wavelength shifts of the two FBGs induced by temperature are
approximately the same when the different pressures are exerted on the sensor. The peak wavelength difference depends only on the exerted pressure. So the simultaneous measurement of the temperature and pressure can be carried out. The line
arity of the sensor is good. The measurement ranges of temperature and pressure are 40℃～110℃ and 0～6MPa, and the temperature and pressure measurement errors are less than 1℃ and 0. 2MPa respectively.

Attribute reduction of a decision table in algebra view and information view

WANG Li-hong(1;2);WU Geng-feng(2)

J4. 2005, 32(1):  156-160. 

Abstract ( 1619 )   Save

Related Articles | Metrics

This paper discusses algebra properties and changing law of entropy for some attribute reduction definitions.
The wrong proposition that possible reduct is equivalent to approximate reduct is corrected, and analysis shows that possible reduct keeps neither a positive region nor conditional entropy unchanged, while approximate reduct and μ-dec
ision reduct can keep positive region and conditional entropy unchanged.

The field distribution in the GTEM Cell

ZHOU Xiao-ping(1);ZOU Peng(1);LIU Chao-yang(2)

J4. 2005, 32(1):  161-164. 

Abstract ( 1718 )   Save

Related Articles | Metrics

The field distribution in the GTEM Cell(1GHz transverse electromagnetic transmission Cell) is discussed. The field distribution in the GTEM Cell is theoretically computed by the 3D FDTD method and is experimentally measured. The process for calculating field distribution in the GTEM Cell by the 3D FDTD means with a number of problems is introduced in detail. Theoretical results agree well with experimental data. It is proved that the variations of the field in the effective region of a GTEM Cell are less than 4dB, which can satisfy the requirements for the measurement of electromagnetic compatibility.