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25 February 2011, Volume 32 Issue 2

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Papers

Energy-efficient sampling and transmission scheme in wireless multimedia sensor networks

Chao SHA,Li-juan SUN,Ru-chuan WANG,Hai-ping HUANG

2011, 32(2):  1-10.  doi:1000-436X(2011)02-0001-10

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An energy-efficient data sampling and transmission method in wireless multimedia sensor networks was proposed.Node’s sensing direction could be adjusted with the help of Voronoi diagram which enhances network coverage level.And energy consumption on sampling was reduced on the basis of periodical sleeping as well as different sampling granularities.Moreover,the transmission overhead was further brought down by means of color block matching.Simulation results show that this method obtains satisfactory performance on prolonging networks lifetime.

Limited feedback SDMA scheme based on quick-match user scheduling for multiuser MIMO systems

Hui YU,Yong-ming HUANG,Lv-xi YANG

2011, 32(2):  11-17.  doi:1000-436X(2011)02-0011-07

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A limited feedback SDMA(space division multiple access)scheme was proposed by constructing a new codebook and developing a related opportunistic scheduling algorithm.In particular,an SDMA codebook was first devised,which had a cluster-based structure and was generated by using a subspace perturbation method.Then,a novel opportunistic scheduling algorithm was proposed to exploit the cluster structure of the devised codebook.The algorithm was capable of rapidly finding a group of channel-matching users together with their preferred precoders.Simulation results demonstrate that in cellular networks,the proposed SDMA scheme outperforms conventional limited feedback SDMA schemes in terms of throughput,with a comparable feedback overhead.

Energy-balance data transmission algorithm with biased random walk

Shu-kui ZHANG,Sheng-rong GONG,Zhi-ming CUI,Jian-xi FAN

2011, 32(2):  18-26.  doi:1000-436X(2011)02-0018-09

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To improve the data transmission performance,a practical algorithm that biased the random walk was proposed,in which the probability function at each step reflects the node available energy with due consideration to delay.Specifically,the transmission range of sensors was decomposed into concentric circular bands rings based on a minimum transmission distance between any pair of sensors,the nodes that lay on or were close to the shortest path between a source and a sink distributed data as proxy forwarders in data transmission from a source to a sink,helped simultaneously balance energy consumption and delay.Moreover,the comparison with other algorithms also provides an ication of the effectiveness of the algorithm.

Dynamic policy access model based on classification concept lattice

Su-yun JIAO,Yan-heng LIU,Da WEI

2011, 32(2):  27-33.  doi:1000-436X(2011)02-0027-07

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A new access model for dynamic polices was proposed after disadvantages of other access models and advantages of concept lattice in getting the intersection set of attr values for two policies was analyzed.The new access model was based on classification concept lattice.Dynamic policies were organized into a concept lattice according to the partial order relation among their attribute values.A novel conflict detection algorithm was proposed based on concept lattice to greatly increase efficiency of conflict detection.The intersection set of attribute values for two policies was got by searching parent-child concepts in the lattice,meanwhile the conflict detection space was reduced.The performance of the conflict detection algorithm was analyzed.Results of simulation show that the algorithm is effective.

Maximum likelihood self-calibration for direction-dependent gain-phase errors with carry-on instrumental sensors:case of deterministic signal model

Ding WANG,Miao PAN,Ying WU

2011, 32(2):  34-41.  doi:1000-436X(2011)02-0034-08

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Aim at the self-calibration of direction-dependent gain-phase errors in case of deterministic signal model,the maximum likelihood method(MLM) for calibrating the direction-dependent gain-phase errors with carry-on instrumental sensors was presented.In order to maximize the high-dimensional nonlinear cost function appearing in the MLM,an improved alternative projection iteration algorithm,which could optimize the azimuths and direction-dependent gain-phase errors was proposed.The closed-form expressions of the Cramér-Rao bound(CRB) for azimuths and gain-phase errors were derived.Simulation experiments show the effectiveness and advantage of the novel method.

Architecture of vulnerability discovery technique for information systems

You-chun ZHANG,Qiang WEI,Zeng-liang LIU,Ying ZHOU

2011, 32(2):  42-47.  doi:1000-436X(2011)02-0042-06

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First,the definition of technical terms about vulnerability discovery were presented.The characters of the targets of vulnerability discovery were Analyzed.The general process of vulnerability discovery was studied.Then,by applying layer construction model way,proposed the architecture construction model of vulnerability discovery technique,which was divided into five layers,and also explained the contents，roles and key techniques of each layer.Finally,the future direction for the technique is that a comprehensive and coordinated method is used,with all the five layers taken into consideration.

Cryptography algorithm for wireless channel of CBTC system

Chao WANG,Li-li LIU,Zhi-hua NIU,Xiang-yong SHI,Huan-guo ZHANG

2011, 32(2):  48-52.  doi:1000-436X(2011)02-0048-05

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As to the disadvantages of RC4 which was used for CBTC system,a new cryptography algorithm based on Montgomery-form ECC was brought forward.Compared with the traditional Montgom elliptic curve,the improved algorithm would resume the value of y-coordinate with more security.In addition,compared with the traditional ECC,it has faster computing speed and can effectively resist timing attack and energy attack.The new Montgomery-form ECC algorithm has accelerated current ECC encoding speed and would make t improvement to the implementation of ECC in CBTC and other wireless communication.

Performance analysis and optimization of cooperative spectrum sensing for maximizing secondary throughput

Mei-ling LI,Chao-wei YUAN,Lin LI,Rui-zhe YANG

2011, 32(2):  53-60.  doi:1000-436X(2011)02-0053-08

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The relationship among SU,detection threshold,bandwidth,spectrum utilization and secondary throughput in cognitive radio networks was analyzed,which indicates the lower false alarm probability,higher spectrum utilization and larger secondary throughput with less SU in C-CSS(censoring based cooperative spectrum sensing),besides,the required detection threshold for maximizing the secondary throughput different with the traditional CSS under given SU number and the objective demand.Based on the NP criticism,an optimal cooperative spectrum sensing algorithm for maximizing the secondary throughput was proposed by solving the mathematic model to obtain the optimal party of SU and detection threshold.Theoretical analysis and simulation results show that the maximized secondary throughput achieved by the proposed optimal algorithm,while maintaining the given detection probability.

DDoS defense with IP traceback and path identification

Guang JIN,Fei ZHANG,Jiang-bo QIAN,Hong-hao ZHANG

2011, 32(2):  61-67.  doi:1000-436X(2011)02-0061-07

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A novel idea to combine both IP traceback and path identification (Pi) was proposed,and malicious packets could be identified and filtered at located upstream nodes.Then a practical packet marking and filtering scheme was proposed.The nodes along the path out of the destination domain deployed Pi.Meanwhile the border router of the destination domain deployed the traceback marking scheme.The victim could retrieve related information from arrived malicious packets.Then Pi-based filtering could be implemented at the border ingresses.A practical marking,storing and filtering scheme was provided in detail.The results of large-scale simulations with authoritative Internet topologies show the scheme is effective to alleviate attack impacts on the victim and upstream links in the destination domain.

Cyclic codes over formal power series rings

Xiu-sheng LIU

2011, 32(2):  68-71.  doi:1000-436X(2011)02-0068-04

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Cyclic and negacyclic codes over formal power series and finite chain rings were studied.By using ring isomorphism and exchange graph,an obtained results of cyclic and negacyclic codes over two classes,Dougherty Liu and Park gave that the projective codes of cyclic codes over the formal power series ring were cyclic codes,sufficient and necessary conditions for cyclic codes gave over this class of rings.Thus it is obvious that projective codes of the cyclic codes over the Chinese product with formal power serious ring are cyclic code.

Experiment on a full-duplex OFDM radio-over-fiber system with 60GHz optical millimeter wave

Ze DONG,Zi-zheng CAO,Lin CHEN,Jian-jun YU

2011, 32(2):  72-76.  doi:1000-436X(2011)02-0072-05

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An integrated full-duplex radio-over-fiber system with 60GHz wireless OFDM mm-wave transmission by using external modulation was proposed and experimentally demonstrated.The experime l results show that the 58GHz optical millimeter-wave will be generated by 29GHz RF resource.2.5Gbit/s OFDM downstream signal are modulated on the 58GHz optical millimeter-wave.The modulated signal can be transmitted over 20k iber,and 3.3m wireless distance can be realized simultaneously.2.5Gbit/s OOK-NRZ upstream data signals are modulated on the reused l wavelength and transmitted over 20km fiber to the central station.

Perceptually optimized model transmission and realtime rendering among wireless network

Bai-lin YANG,Xun WANG,Zhi-geng PAN

2011, 32(2):  77-85.  doi:1000-436X(2011)02-0077-09

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In order to overcome the shortcomings brought by the narrow bandwidth of wireless network,low power consumption and limited resources for mobile computing terminals,a perceptually optimized model transmission and real-time rendering method was propsed.Firstly,a perceptually optimized model simplified algorithm based on the proposed improved salient region measuring model was presented for preserving the visually important vertices as longer as possible.Then,an effective real-time rendering method was developed.With the help of the smart model coding and computing task assigning,the progressive model can be delivered from the server to a mobile terminal quickly and rendered real-time without any redundant local reconstruction computation.The experimental results both on HP210 Pocket PC PDA among real 802.11b wireless network and NS2 simulation environment have shown that the proposed method can achieve visually appealing simplified result and gain real-time interactive rendering for multi-resolution model among wireless network.

Technical Reports

Research on formal description and verification of automated trust negotiation

Shang-yuan GUAN,Wei-guo WU,Xiao-she DONG,De-pei QIAN

2011, 32(2):  86-99.  doi:1000-436X(2011)02-0086-14

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First,a unified ATN formal framework was presented,into which typical negotiation strategies could be reduced.Second,the formal verification of ATN was defined based on the formal framework.The objectives and procedures of the formal verification of ATN were described.Third,several typical negotiation strategies were discussed,and the computational complexity of the corresponding veri ication problems was shown,several conclusions had been obtained.Last,the formal verification of ATN was implemented by using logic programming and model check methods.The experimental results show that the number of rules is a crucial factor in determining the runtime.Both logic programming and model checking are efficient when the number of transition rules is small,and logic programming does not scale as well as model checking.

Method of optimizing MB UWB saturation throughput on PCA

Jin TIAN,Ping-ping XU,Guang-guo BI

2011, 32(2):  100-105.  doi:1000-436X(2011)02-0100-06

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PCA (prioritized contention access) saturation throughput for error channel while stations had same priority in the superframe of BP (beacon period) and hard DRP (distributed reservation protocol) was researched with two dimension Markovian model.The analysis identifies that short frame has bigger saturation throughput than long frame does while there is worse channel condition.The result from theory comput g accords with that from NS2 software simulation in the error range.There is optimal frame length in error channel so that theoretical validation is provided for optimizing link control and improving system saturation throughput performance.

MOADA-SVR:a multivariate online anomaly detection algorithm based on SVR

Ye-kui QIAN,Ming CHEN

2011, 32(2):  106-113.  doi:1000-436X(2011)02-0106-08

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Network anomaly detection is critical to guarantee stabilized and effective network operation.Although PCA-based network-wide anomaly detection algorithm has good detection performance,it cannot satisfy demands of online detection.In order to solve the problem,after traffic matrix model was introduced,a normality model of traffic was constructed using SVR and the sparsification of support vector solutions.Based on these,a multivariate online anomaly detection algorithm based on SVR named MOADA-SVR was proposed.Theoretic analysis showed that MOADA-SVR had lower storage and less computing overhead compared with PCA.Analysis for traffic matrix datasets Internet showed that MOADA-SVR had also good detection performance,approximating PCA.

Broadcast encryption scheme with constant-size public key and private key

Qing-bin WANG,Shao-zhen CHEN

2011, 32(2):  114-119.  doi:1000-436X(2011)02-0114-06

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Using efficiently computable bilinear maps,a new broadcast encryption scheme was proposed.The scheme was proven IND-ID-CPA security in the standard model.In this scheme,the public key and private key are constant size,and the ciphertext size is very short.Moreover,the scheme is fully collusion resistant.Compared with existing broadcast encryption schemes,the new scheme is more appropriate for low storage devices.

Packet size adjustment strategy for fairness in multi-rate and multi-node IEEE 802.11

Wei-qiang XU,Si-ping HU,Ya-ming WANG,Yun-hua ZHANG

2011, 32(2):  120-129.  doi:1000-436X(2011)02-0120-10

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After deeply analyzing the reasons of the unfairness in the multi-rate mechanism,the new strategy,transmission rate-based packet size adjustment (TRPSA) was provided.This strategy guaranteed that each node with different transmit rate could access the wireless channel fairly.The theoretic proof and the extensive simulation validation show that the proposed strategy can achieve the efficient fairness and improve the network performance under the multi-rate multi-node situation.The proposed strategy slightly modifies IEEE 802.11.Thus,it is easy to be implemented and widely applied in the practical network.

Comprehensive Review

Review on 3D audio technology

Fu-liang YIN,Lin WANG,Zhe CHEN

2011, 32(2):  130-138.  doi:1000-436X(2011)02-0130-09

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The principle of 3D audio technology is introduced.The application of signal processing methods is reviewed in 3D audio from the measurement,computation,interpolation,approximation of head-related transfer functions (HRTF) and the methods for crosstalk cancellation.Finally,crrently hot topics in this area are summarized and the future research trends of 3D audio are discussed.

Concise Papers

Code design with high rates based on quasi-orthogonal space-time block code

An-guo WANG,Qiong SHEN,Zhong-er NIE

2011, 32(2):  139-143.  doi:1000-436X(2011)02-0139-05

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In order to meet the needs of high-speed and large-capacity in communication system,the novel non- orthogonal space-time block code with code rates 2 and 1.5 were proposed,respectively.The simplified conditional maximum-likelihood algorithm is adopted to reduce the decoding complexity.The simulation results show that the channel capacities of proposed code are very close to the actual value,and the BER performance is better than that of the orthogonal and quasi-orthogonal codes.

Channel estimation for MIMO SC-FDE systems via time-domain based approaches

Dan-ping LI,Yi LIU,Hai-lin ZHANG

2011, 32(2):  144-149.  doi:1000-436X(2011)02-0144-06

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Circularly orthogonal sequences were designed for the me-domain channel estimation in MIMO SC-FDE systems.Firstly,Chu sequences were chosen as the base sequences,which were added by cyclic prefix and cyclic postfix to construct circularly orthogonal training sequences.The channel impulse response can be estimated by calculating the cross-correlation between the received signal and the corresponding local sequence.Further,a new training sequence structure was presented,in which the original “long” training sequences were replaced by successive and identical “short”sequences.The corresponding estimation algorithm achieves the same performance as “long”sequences based method.Simulation results show that the proposed algorithms can offer good BER performance even at low SNR,due to the successful interference suppression between the antennas and the decrease in the noise variance.

Approach of information security assessment for ATM system based on improved BP model of artificial neural network

Zhi-jun WU,Lu WANG,Rong SHI

2011, 32(2):  150-158.  doi:1000-436X(2011)02-0150-09

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ATM system was divided into 3 layers for the purpose of evaluating its information security.An evaluation model was proposed by using a 3-layer artificial neural network (ANN) based on improved BP model.The major information security indicators of ATM system were used as the training samples,which were adapted to find the intrinsic links between the input and output by learning and training process.An experiment was conducted by using the well-trained ANN network to evaluate the security of ATM system.The experimental results show that the proposed ANN evaluation model can indicate the practical running status of ATM system precisely.It is highly adaptive and fault-tolerant.