2010 Vol. 19, No. 2

Display Method:
A Distributed Decision Making Method inCognitive Radio Networks for SpectrumManagement
GE Yuming, SUN Yi, LU Shan and Eryk Dutkiewicz
2010, 19(2): 195-200.
Abstract:
In order to make full utilization of the
scarce spectrum resources for Cognitive radio networks,
secondary users are expected to exploit the available spec-
trum of primary users. However, when there are several
spectrum bands available, how to select an appropriate one
for the secondary user according to the spectrum quality
and the QoS requirements of di®erent kinds of applications
is a new challenge. In this paper, we propose a new Au-
tomatic distributed spectrum decision (ADSD) method to
solve this problem. ADSD considers multiple spectrum
characterization parameters, in particular, the primary
users' arrival probability, to estimate the quality of the
available spectrum bands. A weight auto-generation mech-
anism is included to automatically determine the weights
of di®erent parameters, thus avoiding the di±culty and ir-
rationality when relying on the users to specify the weights
directly. In addition, in conjunction with the recon¯g-
uration mechanism, ADSD can reduce the rate of spec-
trum hando®s by recon¯guring the transmission parame-
ters rather than making a new decision for the existing
transmission. Simulation results show that without any
users' interference, ADSD can automatically select the ap-
propriate spectrum for transmission and signi¯cantly im-
prove the Cognitive Radio network performance in terms
of throughput and the spectrum hando® rate.
Quantum Two-prover Bit Commitment
YANG Wei, HUANG Liusheng, WANG Yang and LUO Yonglong
2010, 19(2): 201-205.
Abstract:
This paper considers a new bit commit-
ment model named Quantum two-prover bit commitment
(QTPBC) and its physical realization. In a QTPBC scheme
two provers jointly commit a bit to the veri¯er. The two
provers can cooperate and communicate between them to
decide on a common optimal strategy before the interac-
tion with the veri¯er starts, further they are allowed to
share quantum entanglement. But once the interaction be-
gins, the two provers are physically separated and isolated,
and they cannot send both classical and quantum messages
to each other any longer. By virtue of rapid progress in
single photon detection technology, we construct a quan-
tum protocol for QTPBC based on linear code. Detailed
analysis shows that our scheme is of unconditional secu-
rity, i.e., the computing power of participants and poten-
tial eavesdroppers is assumed to be in¯nite. Moreover, the
scheme is proven to be able to tolerate errors due to noise
in practice.
A Decentralized Tuple Space Model with PolicyManagement for Collaboration
XING Jiankuan, QIN Zheng and ZHENG Xiang
2010, 19(2): 206-210.
Abstract:
Decentralized tuple space is an e®ective
paradigm for distributed collaborative applications since
its loose decoupling, availability and °exibility in system's
organization. However, there are very few research results
on its replication and consistency. This paper presents
a decentralized tuple space model to enable tuple update
by creating loose update links among decentralized Tuple
space nodes. Besides, tuples are grouped with tuple types,
the unit of being applied a replication policy, which con-
trols the distribution of replicas. The model is simulated
by Desmo-J. The experiments show that applying di®er-
entiate replication policies used for di®erent purposes is
absolutely necessary, because no single policy is suitable
under all use patterns.
Optimizations and Deoptimizations for EscapeAnalysis in Open World
SHI Xiaohua, WU Gansha, JIN Maozhong and LUEH Guei-Yuan
2010, 19(2): 211-216.
Abstract:
This paper introduced the optimization
and deoptimization technologies for Escape analysis in
open world. These technologies are used in a novel Es-
cape analysis framework that has been implemented in
Open runtime platform, Intel's open-source Java virtual
machine. We introduced the optimization technologies
for synchronization removal and object stack allocation,
as well as the runtime deoptimization and compensation
work. The deoptimization and compensation technologies
are crucial for a practical Escape analysis in open world.
We evaluated the runtime e±ciency of the deoptimization
and compensation work on benchmarks like SPECjbb2000
and SPECjvm98.
An Analysis of the Working/Sleeping Decision inTopology Control of Wireless Sensor Networks
XIONG Yan, JIN Xin and MIAO Fuyou
2010, 19(2): 217-219.
Abstract:
Most Topology control (TC) researches in
wireless sensor networks focus on speci¯c algorithms. This
paper proposes the problem that which criterion should
be adopted for the selection of Connectivity type TC and
Coverage type TC. By de¯ning \density of events" as the
decision criterion, the corresponding threshold values are
computed. Simulations indicate that the criteria analyzed
are directive and reasonable.
Motion Control of Biped Robot Based onParametric Optimum
ZHONG Qiubo, PAN Qishu, HONG Bingrong and PIAO Songhao
2010, 19(2): 220-222.
Abstract:
According to the complexity of optimal
control for the process of falling motion, a method based
on parametric control and the enhancing technique is pre-
sented. The piece-wise constant value is used to approach
the optimal solution of optimal control problem. More-
over, the optimal parameters can be calculated by using
the common mathematical programming. Numerical re-
sults are presented for illustration and experiments are
carried out on real robots.
On Formal Analysis of Cryptographic Protocolsand Supporting Tool
XIAO Meihua, JIANG Yun and LIU Qiaowei
2010, 19(2): 223-228.
Abstract:
Cryptographic protocols are crucial for se-
cure communications and networks, distribution systems
and electronic commerce. Model checking technique and
supporting tool for analyzing cryptographic protocols are
discussed. A model checking technique based on logic of
algorithm knowledge for cryptographic protocols is pro-
posed, which can specify explicitly the intruder model ca-
pabilities. The knowledge completeness of intruder abili-
ties is proved. An e±cient veri¯cation model generating
system is developed based on PDL (Protocols description
language) and SPIN/Promela for cryptographic protocols.
Some optimization strategies are implemented in the sys-
tem to reduce the state explosion complexity, such as par-
tial order reduction, syntactic reorder and static analysis.
More than ten cryptographic protocols are analyzed and
published °aws are rediscovered successfully with the sys-
tem. The veri¯cation system can be used as an e±cient
and reliable tool for evaluation of the network security.
Analytical Expression of ac Stark Shift inTwo-Zone Raman-Ramsey Interactions
WU Wenguo and PENG Suping
2010, 19(2): 229-231.
Abstract:
This paper investigated new properties of
the ac (alternative current) Stark e®ect of three-level atom
system in two-zone Raman-Ramsey interactions. It de-
rived the closed-form expressions of ac Stark shift and shift
phase. Then with the help of numerical computation, it
demonstrated the e®ect of various combinations of laser
intensities, initial atomic populations and laser detuning
on Stark shift and shift phase. Based on analytical ex-
pressions and results of numerical computation the paper
provided useful information for determination of the best
conditions in reduction of the ac Stark shift.
Design and Analysis of a Hash Ring-iterative Structure
SU Shenghui, YANG Yixian, YANG Bo and ZHANG Shaolan
2010, 19(2): 232-236.
Abstract:
The authors propose a new type of hash
iterative structure-the ring-iterative structure with feed-
back which is subdivided into the single feedback ring it-
eration and the multiple feedback ring iteration, namely
SFRI and MFRI. Prove that SFRI is at least equivalent to
the MD structure in security, and MFRI is at least equiv-
alent to SFRI in security (property 1 makes people incline
to believe MFRI is more secure than MD). Analyze the
resistance of MFRI, which results from the joint event on
message modi¯cation, endless loop on message modi¯ca-
tion and incompatibility of the su±cient conditions, to the
multi-block di®erential collision attack. Argue the ine®ec-
tiveness of the D-way second preimage attack on MFRI.
Discuss the time and space expenses of MFRI, and point
out the advantage of MFRI over the tree-iterative struc-
ture and the zipper-iterative structure.
Hybrid System Level Modeling andImplementation of Con¯gurable Processorfor SoC
GUO Wei, WEI Jizeng, MA Zijiao, WANG Zhenghua and LIU Zhuangli
2010, 19(2): 237-240.
Abstract:
To cope with the roaring complexity of
modern SoC designs, system level modeling and simula-
tion are recognized as a must to ful¯ll quick architecture
exploration and hardware/software co-veri¯cation. A hy-
brid system level modeling method for con¯gurable pro-
cessor based on Transport triggered architecture (TTA) is
presented in this paper. We implemented a cycle-accurate
and bit-accurate model at instruction set simulation level
using SystemC to achieve fast simulation and a transaction
level model for standard IP interface for easy SoC integra-
tion. The object oriented modeling technique was used to
cope with the change of the architecture con¯guration. As
a case study, an enhanced TTA-like processor, Tcore, was
designed and plugged into a SoC for system simulation.
Stereo Matching for Face Images Based onFeature Points
WANG Yinghui, XIAO Bing and WANG Qiongfang
2010, 19(2): 241-244.
Abstract:
Stereo matching is the key of reconstruct-
ing 3D face model from 2D face images and Barnard's al-
gorithm is one of the classical stereo matching algorithms
based on feature points. In order to enhance the stability
of extracting feature points, reduce computational com-
plexity and minimize the e®ect of subjective factors, in this
paper, Barnard's algorithm of edge point matching was im-
proved from two aspects: edge point sets of left and right
face images were extracted with dyadic wavelet transform,
rather than comparing gray values of adjacent pixels; on
the other hand, edge points in binocular stereo face images
were matched under epipolar constraint in parallel binoc-
ular stereo matching. Experimental results demonstrate
that stability and e±ciency of stereo matching algorithm
are both improved.
Dynamic Path Planning for Mobile Robot Basedon Improved Genetic Algorithm
LIU Changan, YAN Xiaohu, LIU Chunyang and LI Guodong
2010, 19(2): 245-248.
Abstract:
The paper proposes the dynamic path
planning method of mobile robot based on improved ge-
netic algorithm. Firstly, to ensure the safety of the robot
e®ectively, the improved visual graph and the conception
of safety coe±cient are presented. Secondly, to avoid the
local optimum, the paper replaces the mutation individual
with a better individual searched by hill-climbing method.
To increase the convergence speed, the paper updates the
colony by the rule of the particle swarm optimization.
Thirdly, °oat-point coding is proposed in the improved ge-
netic algorithm. The ¯tness function includes the length
and the total slope of the path in dynamic path planning.
Finally, it emulates the dynamic path planning for mobile
robot based on improved genetic algorithm. From the re-
sults, it can see that the path planning method is viable
and e±cient.
Efficient Fuzzy Vault Based on Pairing and ItsApplication to Fingerprint Encryption
FU Bo and LI Jianping
2010, 19(2): 249-255.
Abstract:
Fuzzy vault (FV) scheme, proposed by
Juels and Sudan, is intended to develop new concepts to
bind cryptographic security into biometric authentication
to improve security and protect privacy. But FV is vul-
nerable to some attacks, such as Attacks via record mul-
tiplicity or correlation attacks, Surreptitious key-inversion
attack and Blended substitution attacks. In this paper, a
novel biometric encryption scheme, named Efficient fuzzy
vault (EFV), is developed using pairing-based cryptogra-
phy. EFV scheme provides a higher level of security than
FV as adopting random points instead of chaff points to re-
sist the attacks that FV has difficulty to overcome. In addi-
tion, a complete implementation procedure of fingerprint-
based EFV, based on the automatic alignment of minutiae
converted in polar coordinates using a reference point, is
developed. The security analysis and experiment results
show that EFV is a promising scheme for biometric en-
cryption.
A Real-Time Image Registration AlgorithmBased on Feature-Index
GAO Feng, LI Yanghuan and LI Xiang
2010, 19(2): 256-260.
Abstract:
A Feature-Index based algorithm that uses
similarity information and spatial coherence is presented in
the paper. It especially ¯ts to the case that the base image
is very large and real-time property is needed. The algo-
rithm is divided into four steps: ¯rstly extract features
from base image, and establish feature-index table before-
hand; then extract corresponding features from sensed im-
age and use the feature-index table to match them with
those from base image; thirdly, fuse the matching results
of Main line pairs (MLPs) and contours; ¯nally, solve the
transformation parameters using the intersection points of
MLPs and centers of contours and complete registration.
The experiment results show that the proposed algorithm
is accurate and e®ective.
A Variational Approach for Image SegmentationUsing Tensor Voting
WANG Wei and PI Ling
2010, 19(2): 261-264.
Abstract:
We presented an improved geodesic active
contour model for image segmentation. This method com-
bines the geodesic active contour model and the tensor
voting framework. We added in°uence of tensor voting in
the edge-detector function. The proposed model is more
sensitive to edges. It can detect weak boundaries of de-
sired objects in some images with low contrast. Using this
method, we don't have to spend time to ¯nd some suit-
able parameter which is necessary in the geodesic active
contour model. Numerical results show the e®ectiveness.
CNS/Pulsar Integrated Navigation UsingTwo-level Filter
LIU Jin, MA Jie and TIAN Jinwen
2010, 19(2): 265-269.
Abstract:
To improve the position accuracy, a CNS
(Celestial navigation system)/pulsar integrated navigation
system with clock drift is proposed. In the pulsar navi-
gation subsystem, the epoch-di®erence method is adopted
to eliminate clock drift, but it induces colored noise. The
two-level ¯lter, which is composed of an UKF (Unscented
Kalman ¯lter) and an H1 ¯lter in series connected, is
proposed for fusing the data from the celestial navigation
and pulsar navigation subsystems. The celestial naviga-
tion subsystem adopts the UKF because of its good perfor-
mance in nonlinear estimation, while the pulsar navigation
subsystem utilizes the H1 ¯lter due to its robustness to
colored noise. Compared with CNS and two CNS/pulsar
integrated navigation methods without two-level ¯lter, the
proposed method can provide higher navigation accuracy.
Simulation results show that the position estimation ac-
curacy of the proposed method can achieve 140m in the
presence of clock drift.
Accelerometer-based Chinese Tra±c PoliceGesture Recognition System
YUAN Tao and WANG Ben
2010, 19(2): 270-274.
Abstract:
When an automatic tra±c light system is
not working e.g. due to tra±c jam, it is necessary for traf-
¯c police to control the tra±c by gestures. In this paper,
the design of a system to synchronize tra±c lights with
tra±c police gestures is presented. The gesture data are
extracted by ¯xing a 3-axis accelerometer on the back of
each hand. Signals obtained from the accelerometers are
transformed into arm motion and palm orientation. A hi-
erarchical classi¯er is designed to recognize the gestures, in
which fuzzy rules are used to enable vague gesture recog-
nition. An embedded micro-processor system has been de-
veloped for real-time gesture recognition. Wireless mod-
ules are used for communication and a digital compass is
used to identify the direction, to which a tra±c policeman
faces. The integrate system has been tested, and the fea-
sibility of the system to synchronize tra±c lights has been
demonstrated.
Filtering LDoS Attack by FIR Filter
WU Zhijun and SHI Zhen
2010, 19(2): 275-278.
Abstract:
Low-rate denial of service (LDoS) attack is
a new class of DoS, which exploits TCP's congestion con-
trol mechanism. LDoS attack can reduce the throughput of
the attacked link by sending low-rate packets in the way of
periodic pulse. Because of its low-rate characteristic, it can
elude the monitor of traditional detection approach. Most
applications in the Internet use TCP protocol, so the dam-
age of LDoS attack is not inferior to the traditional °ood
type DDoS attack. The characteristics of LDoS attack in
frequency domain were analyzed, by adopting digital sig-
nal processing technology. The ¯ltering algorithm was de-
signed as a Finite impulse response (FIR) ¯lter to eliminate
the illegitimate frequencies in frequency domain. Exper-
iments result show that 92.88% of LDoS attack energy is
¯ltered, and 19.75% of normal energy is eliminated.
BPSO and Parallel FDTD Algorithm for RCSReduction Design of Target GeometricParameters
WANG Wei and LI Mingzhi
2010, 19(2): 279-282.
Abstract:
This paper focuses on high-speed design of
geometric parameters of any given target for Radar cross
section (RCS) reduction. The Binary particle swarm op-
timization (BPSO) and the Finite-di®erence time-domain
(FDTD) method are combined to acquire a given object's
optimum geometric parameters that would lead to its min-
imal monostatic RCS. To promote the computation speed
as well as the computation capacity in a further way, a par-
allel FDTD code is imported in this paper. A basic strat-
egy to reduce RCS of a canonical target is proposed. As an
illustration of the ability of the optimizing method, the al-
gorithm is applied to optimize the position and the width of
the slot, which may reduce the monostatic RCS. To verify
the e®ectiveness of the algorithm, all possible conditions
in this problem are simulated and it is well shown that
the optimizer could search out the minimal or subminimal
solution quickly and e®ectively.
Moment Invariants for Color Constant ImageDescription
LI Bing, XU De and LANG Congyan
2010, 19(2): 283-287.
Abstract:
An important class of color constant im-
age descriptors is based on image derivatives. However,
these derivative-based descriptors are sensitive to blurring
changes of image, and also lose much color information in
uniform regions. Aiming at overcoming these drawbacks,
the contributions of this paper are in three-folds: First,
by introducing 3D moment invariants, we propose a color
constant descriptor in RGB color space, which can char-
acterize original image color content. Second, we de¯ne
a 2D edge-based color space based on the diagonal-o®set
re°ectance model. A novel color constant descriptor in the
proposed edge-based color space is presented by using mo-
ment invariants. This descriptor can characterize edge im-
age with nearly no sensitivity to image blurring. Finally,
we combine the aforementioned descriptors to construct
the third color constant descriptor, which can describe not
only original image color content but also the edge image
color feature. The experiments on scene recognition show
that all these descriptors have satisfying performance un-
der various light sources. Furthermore, all these proposed
descriptors are insensitive to image a±ne transformations
and blurring changes.
Details-preserved Skin Re-tendering UsingImproved NLEMD
ZHAO Jing and LIN Hongfei
2010, 19(2): 288-290.
Abstract:
The Neighborhood limited empirical mode
decomposition (NLEMD) is improved in the local mean
computation using re¯ned symmetrical extrema distribu-
tion. The images are decomposed into the IMFs using the
improved NLEMD. Then, the IMFs are ¯ltered using one
adaptive ¯lter to remove the spots making the skin look
aging. The adaptive ¯lter is based on the IMFs' local statis-
tics, which is estimated using the fast approach. The skin
re-tendering algorithm in this paper makes the skin more
tender than other approaches without losing the necessary
details of the skin.
Power Allocation in Decode-and-ForwardCooperative OFDM Systems Using Perfect andLimited Feedback
ZHANG Guangchi, ZHAN Weixu and QIN Jiayin
2010, 19(2): 291-295.
Abstract:
To maximize the spectral e±ciency of
a Decode-and-forward (DF) cooperative Orthogonal fre-
quency division multiplexing (OFDM) system, we ¯rst pro-
pose the optimal power allocation algorithm when per-
fect Channel state information (CSI) feedback is available.
Since perfect CSI feedback is unrealistic, we further pro-
pose a power allocation scheme using limited feedback,
where the power allocation vectors for the source and re-
lay are limited in two ¯nite power allocation tables respec-
tively. In this scheme, the destination chooses the power
allocation vectors for the source and relay, and feeds the
indices of the vectors back. The power allocation tables
are designed by using the Lloyd algorithm. Simulation re-
sults show that the perfect CSI feedback power allocation
scheme achieves the best performance, and that the per-
formance of the limited feedback scheme lies between the
perfect CSI scheme and the scheme with no CSI.
Network Lifetime Optimization under QoSConstrains for Coded Cooperative Networks byDynamic Resource Allocation
ZHANG Yan, SHENG Min, LI Jiandong, TIAN Ye, YAO Junliang and TANG Di
2010, 19(2): 296-302.
Abstract:
Network lifetime optimization is a vital and
challenging design issue for battery-operated wireless net-
works, which guarantee uninterrupted information trans-
mission in wireless networks. Fortunately, emerging as
a new communication paradigm, cooperation communica-
tion provides an e®ective way to share resource among net-
work nodes that can be used to extend network lifetime. In
this paper, the dynamic resource allocation strategies are
introduced to optimize the network lifetime under Qual-
ity of service (QoS) constraints for coded cooperative net-
works, which consider power control, multi-relays selec-
tion and Level of cooperation (LOC) adjustment jointly.
An optimization model for minimizing and balancing the
energy consumption under QoS constrains is formulated
based on a TDMA scenario. When the LOC is constant,
the closed form optimal solution is got by Karush-Kuhn-
Tucker (KKT) conditions, which results in an optimal re-
source allocation strategy. Based on the solution, a sub-
optimal scheme is further proposed for a variable LOC.
Simulation results show that our schemes can dramatically
prolong network lifetime and support higher QoS levels
compared with other existing cooperative resource alloca-
tion schemes.
Research on the Programming Language forSymmetric Cryptographic Algorithms
LI Fenghua, YAN Junzhi, XIE Rongna, and MA Jianfeng
2010, 19(2): 303-306.
Abstract:
The Programming language for symmetric
cryptographic algorithms (PLSCA) is proposed. The de-
tailed speci¯cation of the syntax of PLSCA is presented,
and the cipher of IDEA is described using PLSCA as an
example. Using PLSCA, the cryptography designers could
describe the structure of symmetric cryptographic algo-
rithms in a formal way, exchange their ideas and algorithm
details, test and analyze the symmetric cryptographic al-
gorithms conveniently and rapidly. PLSCA may improve
the testing e±ciency of new algorithms. It is adapt to as-
sist the design and automatic analysis for symmetric cryp-
tographic algorithms, and it may be used as a standard
language to submit new algorithms to the evaluation sta®.
Upper Bounds on Lifetime of Three DimensionalExtended UWB Sensor Networks
XU Juan, JIANG Changjun, GUO Aihuang, HONG Yongfa, LI Shu and WANG Cheng
2010, 19(2): 307-312.
Abstract:
The upper bounds on lifetime of three
dimensional extended Time hopping impulse radio Ultra-
wide band (TH-IR UWB) sensor networks are derived us-
ing percolation theory arguments. The TH-IR UWB sen-
sor network consists of n sensor nodes distributed in a cube
of edge length n1=3 according to a Poisson point process
of unit intensity. It is shown that for such a static three
dimensional extended TH-IR UWB sensor network, the
upper bound on the lifetime is of order O(n¡1), while in
the ideal case, the upper bound on the lifetime is longer
than that of a static network by a factor of n2=3. There-
fore sensor nodes moving randomly in the deployment area
can improve the upper bound on network lifetime. The re-
sults also reveal that the upper bounds on network lifetime
decrease with the number of nodes n, thus extended TH-
IR UWB sensor networks aren't prone to be employed in
large-scale network.
Secure Certi¯cateless Encryption with ShortCiphertext
SUN Yinxia and ZHANG Futai
2010, 19(2): 313-318.
Abstract:
Certi¯cateless public key cryptography was
introduced to solve the key escrow problem in identity
based cryptography while enjoying the most attractive cer-
ti¯cateless property. In this paper, we present a secure
Certi¯cateless encryption (CLE) scheme with short cipher-
text. The ciphertext length is at least jmj-bit (the length
of a plaintext) shorter than the existing CLE schemes
while retaining similar e±ciency of computation. The new
scheme is provably secure against adaptive chosen cipher-
text attacks in the random oracle model.
The Chen-Mobius Digital Communication Systemand It's Implement by FPGA
LING Chaodong, CHEN Fang and SU Wuxun
2010, 19(2): 319-323.
Abstract:
In addition to modern digital communica-
tion systems, the new coherent modulation-demodulation
systems by two classes of the oblique-orthogonal function
set-the Chen-Mobius transform-were applied to the com-
munication systems. Then the new digital signal commu-
nication system performance was simulated by the MATA-
LAB and compared with the traditional system by the sys-
tems ¯gures of error rate to S=N. Those results showed
that the new system has excellent performances to resist
the strong noise and interference. Then the system imple-
mentation by FPGA was also analyzed in some detail.
E±cient Secure Multiparty ComputationalGeometry
LI Shundong, WANG Daoshun and DAI Yiqi
2010, 19(2): 324-328.
Abstract:
Secure multiparty computational geome-
try is an important ¯eld of Secure multiparty computation
(SMC). We ¯rst present an SMC protocol for comput-
ing the area of a triangle using symmetric cryptographic
method, which is of independent interest in SMC, then use
it to solve the point inclusion problem of convex polygon,
and further solve the inclusion problem of concave polygon.
Compared with existing solutions, these new protocols are
much more e±cient. It is proved, by well accepted sim-
ulation paradigm, that all the protocols proposed in this
paper are secure.
Remote Generation of Quantum CommunicationChannel with Continuous Variable via BeamSplitters
ZHOU Qingping, ZHANG Yanliang, ZHOU Fang, WANG Xiaobo, XU Hongzhi and FANG Maofa
2010, 19(2): 329-332.
Abstract:
The experimentally feasible scheme of re-
motely generating continuous variable quantum entangled
communication channel based on beam splitters is pro-
posed. It is showed that the long-haul quantum communi-
cation channel can be established by means of an assisted
single-photon entangled state and a pair of single-mode
squeezed vacuum states. The degree of entanglement of
the desired continuous variable entangled channel is only
related with the assisted beam splitter when the other two
parallel ones are of the same parameter values. The suc-
cess probability of creating maximal entangled channel can
be enhanced with the increasing of beam splitter re°ec-
tion coe±cients and decreasing of squeezing parameters.
Furthermore, the puri¯cation of success probability is dis-
cussed for imperfect photo-detectors.
On the Outage Capacity of MIMO Systems withPeriodic Feedback
LI Weihua and JIAO Bingli
2010, 19(2): 333-338.
Abstract:
This paper considers the Multiple-input-
multiple-output (MIMO) systems with periodic feedback
under the assumption that the channel state remains quasi-
static within a fading block and varies from one block to the
next based on Markov random process. It is assumed that
the Channel state information (CSI) is perfectly known at
the receiver and fed back to the transmitter once every
period. Given the feedback-capacity constraint in terms of
maximum number of feedback bits per block, the relation-
ship between the outage capacity and the feedback rate
is analyzed. The analysis shows that the outage capacity
is a non-monotonic convex function of the feedback rate
and there exists the maximum value of the outage capac-
ity. Then, to maximize the outage capacity, the optimal
feedback rates are given by numerical results.
Parity Check Network Coding for WirelessCooperative Communications
DU Bing and ZHANG Jun
2010, 19(2): 339-344.
Abstract:
We develop a cooperative decode-and-
forward strategy of distributed Source-Relay network cod-
ing for a three-node relay model, in which Relay and
Source both send their own messages to Destination.
First, we present a cooperative communication protocol to
achieve decode-and-forward capacity by leveraging trans-
mit rates between Source and Relay and designing dis-
tributed Source-Relay network coding accordingly. After-
wards, multi-dimension Low-density parity-check (LDPC)
code is constructed as a layered structure, where Source
LDPC, Relay LDPC, and network LDPC code are organi-
cally integrated to realize a distributed design. Our design
randomly embeds network-coded message into the layered
structure as e®ective extra checks o®ering side informa-
tion for both Source and Relay. Based on derivation of the
algebraic relationship between constituent codes, a good
multi-dimension LDPC code pro¯le is generated. Mean-
while, network coding complexity maintains linear to the
block length. The coding scheme is demonstrated to ap-
proach decode-and-forward capacity and still provides ef-
fective spatial diversity.
Threshold Proxy Re-signature Schemes in theStandard Model
YANG Xiaodong and WANG Caifen
2010, 19(2): 345-350.
Abstract:
A (k; n) threshold proxy re-signature
scheme distributes the re-signature key of the delegatee
and the delegator. The re-signing ability to n proxies in
a way that any set of k or more honest proxies can col-
laborate to re-sign, while any set of k ¡ 1 proxies cannot.
We propose two threshold proxy re-signature schemes with
trust dealer, which are both proved secure in the standard
model. Threshold proxy re-signature schemes are based on
the Computational Di±e-Hellman (CDH) problem with-
out random oracles. The schemes satisfy the properties
of bidirectionality, non-interactivity, multi-use and private
proxy. Meanwhile, the re-signature share generation and
veri¯cation algorithms are non-interactive and e±cient.
Digital Random Sequence Generation Algorithmand VLSI Implementation
CUI Wei, WU Siliang
2010, 19(2): 351-355.
Abstract:
A VLSI array synthesizing digital ran-
dom sequence algorithm is proposed, and its Application-
speci¯c integrated circuit (ASIC) design of the General
random number generator (GRNG) which can generate
digital random sequence with uniform distribution, expo-
nential distribution, Rayleigh distribution and Gaussian
distribution is introduced. In this algorithm, the Box-
Muller equation is adopted for real-time generating ran-
dom number using hardware, and one improved Taus-
worthe sequence generating principle is proposed to speed
up the generation and improve the signal quality. More-
over, the pipelined Coordinate rotation digital computer
(CORDIC) mapping algorithm is used to increases the
throughput. The proposed GRNG is implemented with
SMIC one-poly six-metal 0.18¹m CMOS technology. The
ASIC core occupies 1:8 £ 1:8mm2 die area which generates
16-bit or 32-bit samples up to 4¾, the peak throughput
of the ASIC is 420 million samples per second, and the
peak power dissipation, which includes the power of I/O,
is 416mW in active mode, and 106mW in standby mode
respectively in typical operation condition.
Ramose RAIM: A Multiple-Failure DetectionAlgorithm Design for Civil Aviation
ZHANG Xinyuan, HUANG Zhigang, LI Rui
2010, 19(2): 356-359.
Abstract:
With the advent of Galileo and Chi-
nese Compass, GNSS navigation technologies will develop
rapidly. However, as the number of navigation satellites
in view will increase, the fault probability will rise. This
paper calculates the multi-fault risk of multi-constellation
satellite navigation system in terms of MOPS. It is high-
lighted that the probability of either one-fault or double-
faults is higher than integrity requirement. The paper also
describes a snap-shot ramose RAIM technology to protect
civil aviation users in multiple-fault case. In this condition,
a series of FDE calculation is adopted to separate satel-
lites in sight into several groups. Therefore the problem
will transform into several single-fault case, which current
RAIM can solve. Simulation results verify that this tech-
nique is proper to solve both single-fault and double-fault
problem of civil aviation caused by application of multi-
constellation GNSS.
A New 6D Magnetic Localization Technique forWireless Capsule Endoscope Based on aRectangle Magnet
YANG Wan'an, HU Chao, Max Q.H. Meng, DAI Houde, CHEN Dongmei
2010, 19(2): 360-364.
Abstract:
To build a wireless active endoscope with
external guidance for controllable and interactive GI track
diagnosis, a real time system for 3D localization and 3D
orientation is necessary. An approach is to enclose a small
rectangle permanent magnet in the capsule. The magnetic
¯eld, produced by the rectangle magnet around the body,
can be detected by magnetic sensors outside the patient's
body. With these sensor data, the 3D localization and 3D
orientation parameters can be computed by the nonlinear
optimization algorithm based on the mathematic model of
the rectangular magnet's magnetic ¯eld. Simulation exper-
iments show that the proposed algorithm works e®ectively,
and has good accuracy and time e±ciency when the initial
guess of the parameters are within some predetermined
ranges.
New Techniques for Multi-mode SatelliteNavigation Receiver
LI Rui, WANG Yongchao, ZHANG Jun, ZHU Yanbo
2010, 19(2): 365-368.
Abstract:
| Multi-mode satellite navigation receivers
have to endure heavier computation load because of huge
increment of visible satellites, in hybrid GPS, GLONASS,
Galileo and Compass navigation scenario. To solve these
problems, in the paper, two new technologies are presented
to decrease computation load: Fast satellite selection algo-
rithm (FSS) and Novel weighted least-squared positioning
algorithm (NWLS). Di®erent with conventional methods,
FSS is based on satellite elevation and azimuth. Firstly,
all visible satellites are classi¯ed by elevation, with three
sections: low, medium and high elevation. Then, parts of
satellites in medium elevation section are excluded through
sorting, di®erencing, and ratio of high elevation satellites
and low elevation satellites. As to NWLS positioning al-
gorithm, ionosphere delay and other error are analyzed
separately ¯rstly; then weighted observation matrix is cre-
ated according to two kinds error and satellite position.
The matrix is employed in receiver position calculation.
With satis¯ed positioning accuracy, FSS algorithm is able
to decrease computation load by about 20»30%. In conclu-
sion, FSS and NWLS algorithm are e±cient and e®ective
to decrease load of receiver; they are proper to integrated
satellite navigation application scenario.
GPS Multipath Signal Estimation Based on AllPhase DFT
YANG Dongkai, YAO Yanxin, GUO Jia
2010, 19(2): 369-372.
Abstract:
The GPS multipath signal model is given
and analyzed. The all phase DFT (apDFT) is proposed
as a new spectral analysis way, which makes full use of
(2N ¡ 1) samples to do linear transform into N point se-
quence called all phase signal. Phase di®erence method is
integrated with apDFT to determine the accurate signal
frequency through calculating the two phase value for the
two sequences' DFT result, i.e. one is from point 1 to point
(2N ¡1) and the other is from (N +1) to (3N ¡1) separately.
The application of the proposed method on GPS multipath
signal estimation is analyzed, which has multiple frequen-
cies components. Monte Carlo simulation results based on
GPS simulator data show that the apDFT and the integra-
tion with phase di®erence method could give the accurate
frequency and precise phase estimation in both ideal and
noisy environments.
Digital Polarization Agile Monopulse DetectorBased on Microstrip Antenna Array withLinearly Polarized Subarrays
XU Qiang, YU Weihua, SUN Houjun, LU Xin
2010, 19(2): 373-377.
Abstract:
A digital polarization agile monopulse de-
tector was presented. Detection work°ow, method of
virtual polarization synthesizing and method of digital
monopulse angle error extraction based on variable polar-
ization antenna with linearly polarized subarrays were pro-
posed. Polarization agile was realized by utilizing digital
controlled phase shifters in multichannel T/R module. The
gain of antenna array can be improved and the beamwidth
of cross polarization less than ¡15dB can be widened by ap-
propriately increasing the number of subarray. The mea-
sured results show the availability of the detector and the
e®ectiveness of virtual polarization synthesizing and digital
monopulse angle error extraction method.
A Technology to Generate Fast-Edge PulsesUsing Step Recovery Diode
GOU Yongsheng, LIU Baiyu, BAI Yonglin, OUYANG Xian, ZHANG Wei, LI Yan, XUE Yingdong
2010, 19(2): 378-380.
Abstract:
A rectangular pulse generator circuit with
fast rising and falling edge will be presented in this pa-
per. The generator circuit was designed by controlling the
quantity of carriers in the middle layer from regulating
forward current of the SRD (Step recovery diode), and
then indirectly controlling the pulse width. It is based on
the principle that large reverse current will °ow through
the diode and last for a relatively long time when it is re-
verse biased. Experimental results have been analyzed in
physical level. They are tallied with theoretical results.
The circuit can generate rectangular pulses with rise time
about 150ps, fall time about 250ps, amplitude about 10V
and pulse width adjustable from 1ns to 10ns in 50­ load.
The trig jitter is less than 5ps and the amplitude jitter is
better than 4%.
Subband Implementation for Wideband RadarClutter Suppression and Target HRRPEnhancement
DAI Fengzhou, LIU Hongwei, WU Shunjun
2010, 19(2): 381-385.
Abstract:
In this paper, we address the method of
subband implementation for wideband radar clutter sup-
pression and target High resolution range pro¯le (HRRP)
enhancement. The Doppler dispersion is overcome by
separate weighting processing in the individual subbands.
The optimal weight vectors are obtained by minimizing
the Mean square error (MSE) between the reconstructed
target HRRP and the actual target HRRP. The MMSE
weight vectors require the actual target HRRP as a prior
knowledge and cannot be implemented in practice, as a
compromise the Minimum variance distortionless response
(MVDR) weights are used. Several simulation results are
given to illustrate the enhanced performance of target
HRRP obtained by the methods proposed in this paper.
Large-Signal Simulations of a Novel FoldedWaveguide Traveling-Wave Tube
LIAO Mingliang, WEI Yanyu, HE Jun, GONG Yubing, WANG Wenxiang, Gun-Sik Park
2010, 19(2): 386-388.
Abstract:
A novel Folded waveguide (FW) ampli¯er
for Traveling-wave tubes (TWT) was investigated. It is
formed by adding rectangular grooves periodically to the
bends of a normal FW. In order to test its performance, a
three-dimensional Particle-in-cell (PIC) code MAGIC was
used to simulate the large-signal beam-wave interaction. It
proves to be a potential device for producing more than two
times higher Continuous wave (CW) power with a much
shorter circuit compared to a normal FW. The band per-
formance is also good in above 2GHz. Furthermore, the
novel FW e®ectively improves the problem that gain of a
normal FW decreases at higher working frequencies due
to diminishing of interaction impedance. This novel FW
therefore promises a high power and miniaturized circuit
for millimeter wave TWT.