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25 February 2014, Volume 35 Issue 2

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academic paper

Improved multi-bits flipping algorithm for high-speed LDPC decoding

Ke-xiang MA,Ji-cheng SUN,Meng WANG,Yu-ming ZHANG,Hai-lin ZHANG

2014, 35(2):  0-124.  doi:10.3969/j.issn.1000-436x.2014.02.016

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In order to improve the decoding speed of the RRWBF algorithm, a multiple-bits selection mechanism was proposed to accelerate the decoding convergence speed of the RRWBF algorithm. However, the RRWBF algorithm with the multiple-bits selection mechanism will appear the bit-repeated flipping, which can impair the decoding performance of the RRWBF algorithm. Hence, a bit-repeated flipping elimination mechanism was proposed to reduce the bit-repeated flipping in the process of the multiple-bits flipping decoding. Simulation results show that the RRWBF algorithm with the multiple-bits selection and the repeated flipping elimination mechanism has a much faster decoding speed at the cost of a little decoding performance loss compared with the RRWBF algorithm.

Image enlargement research baised on anisotropic complex diffusion coupling to shock filter

2014, 35(2):  1-8. 

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In order to improve adaptability, the image enlargement method was proposed using improved anisotropic complex diffusion and adaptive Shock filter. For the enlargement of the noiseless image, an improved anisotropic complex diffusion was coupled to shock filter, which adaptively changes the diffusion threshold according to local variance, dividing diffusion time by the diffusion parameter of the image’s imaginary part to remove the diffusion character dependence on the diffusion time, especially the linear diffusion character at the beginning of the diffusion. The noisy image was enlarged by using the adaptive threshold anisotropic complex diffusion filters according to pixel’s local variance coupling with shock filters constrained by pixel’s local variance to enhance the blurred edges. The adaptive threshold anisotropic complex diffusion detects the edge and noise through the combination of local variance and smoothed second derivative of the image, and the proposed method enhances the edge and smoothed the noise, containing the advantage of complex diffusion, as well as preserving the ramp structure and avoiding the staircase effective. The simulations prove prominent performance of the proposed method is not only for noiseless image but also for the certain gauss noisy image.

academic paper

Image enlargement research baised on anisotropic complex diffusion coupling to shock filter

Zhi-hong XI,Tao HAI

2014, 35(2):  1-8.  doi:10.3969/j.issn.1000-436x.2014.02.001

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In order to improve adaptability, the image enlargement method was proposed using improved anisotropic complex diffusion and adaptive Shock filter. For the enlargement of the noiseless image, an improved anisotropic com-plex diffusion was coupled to shock filter, which adaptively changes the diffusion threshold according to local variance, dividing diffusion time by the diffusion parameter of the image's imaginary part to remove the diffusion character dependence on the diffusion time, especially the linear diffusion character at the beginning of the diffusion. The noisy image was enlarged by using the adaptive threshold anisotropic complex diffusion filters according to pixel's local variance coupling with shock filters constrained by pixel's local variance to enhance the blurred edges. The adaptive threshold anisotropic complex diffusion detects the edge and noise through the combination of local variance and smoothed second derivative of the image, and the proposed method enhances the edge and smoothed the noise, containing the advantage of complex diffusion, as well as preserving the ramp structure and avoiding the staircase effective. The simulations prove prominent performance of the proposed method is not only for noiseless image but also for the certain gauss noisy image.

Novel extended cyclic MUSIC algorithm based on uniform circular array

2014, 35(2):  2-15. 

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By introducing cyclostationary theory into the estimation of direction of signal of arrival, a novel extended cyclic MUSIC algorithm based on uniform circular array was developed. The proposed method could eliminate both noises and interferences in the same frequency band by exploiting simultaneously the information contained in both cyclic correlation matrix and cyclic conjugate correlation matrix of the extended array data vector. It has the ability to select desired signals and ignore interferences from the received data. Simulation results demonstrate that the proposed algorithm has a high DOA estimation accuracy and multi-signal resolution. On the other hand, the proposed method also breaks through the limitation of the classic MUSIC algorithm in which the number of source signal cannot be greater than the number of element in the receiving array.

User similarity-based collaborative filtering recommendation algorithm

2014, 35(2):  3-24. 

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Collaborative filtering recommendation algorithms widely used in e-commerce, recommend interesting content for users from massive data resources by studying their preferences and interests. The focus of similarity and evaluation have been changed when applied to social networks, however, they cause low efficiency and accuracy of the recommendation algorithms. User similarity was introduced for redefining the attribute similarity and similarity composition as well as the method of similarity calculating, then a new collaborative filtering recommendation algorithm based on user attributes was designed and some methods for user satisfaction and quality of recommendations were presented. The experimental result shows that the new algorithm can effectively improve the accuracy, quality and user satisfaction of recommendation system in social networks.

Data forwarding mechanism based on dynamical coding nodes managing for intermittent connectivity wireless network

2014, 35(2):  4-32. 

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The limited network resources can be utilized effectively by the network coding method in intermittent connectivity wireless network, but the number of coding nodes should be dynamically adjusted according to network status. To effectively improving the network resources utilization, a data forwarding mechanism based on dynamically managing coding nodes for intermittent connectivity wireless network was proposed. According to the estimated results of current network status, the optimal number of required coding nodes could be determined with the distributed manner. Furthermore, the social property and available resources were considered for coding nodes selecting to achieve reliable data forwarding with the lower overhead. Results show that the connection opportunities between nodes can be exploited adequately by our mechanism; moreover, the utilization of network resources can be improved dramatically.

Novel construction of forward-secure public-key encryption in the standard model

2014, 35(2):  5-39. 

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All existing provably secure forward-secure public-key encryption schemes in the literature were only proven to be chosen-plaintext secure. A novel forward-secure public-key encryption scheme without random oracles was proposed. Under the hardness of the truncated decision q-augmented bilinear Diffie-Hellman exponent problem, the proposed scheme was proved to be chosen-ciphertext secure in the standard model. In the proposed scheme, the running time of decryption algorithm and the size of ciphertext are both independent on the total number of the time periods. Compared with the previous forward-secure public-key encryption schemes in the literature, the proposed scheme has obvious advantage in security and efficiency.

Preimage and pseudo-collision attacks on 29-step SM3 hash function with padding

2014, 35(2):  6-45. 

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The security of SM3 hash function was revaluated by using the meet-in-the-middle attack. The preimage and pseudo-collision attack on 29-step SM3 hash function (from the 1-st step) with padding was presented. The time com-plexities are 2254 and 2125 respectively. Therefore, the 29-step SM3 hash function is not immune to preimage and pseu-do-collision attack.

Location prediction algorithm based on movement tendency

2014, 35(2):  7-53. 

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A location prediction algorithm based on movement tendency (LP-MT) was proposed, which not only buils moving object’s historical activity model borrowing from Markov thinking, but also added movement tendency as an important reference of location prediction. Besides, each of the historical stay regions was considered as a candidate of future location. According to the characteristics of the future location, algorithm results were divided into prediction locations and recommendation locations. Experiment results on real dataset show LP-MT method can ensure good efficiency and improve the accuracy by 10% compared with the existing algorithms.

Universally composable secure multiparty computation protocol with fairness

2014, 35(2):  8-62. 

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The fair problem of secure multiparty computation protocol was investigated in the universally composable framework. A fair secure multiparty computation model with ideal functionalities was firstly formulated such as a fair secure multiparty addition computation and a fair secure multiparty multiplicative computation. Next a fair addition computation protocol and a fair multiplicative computation protocol based on the bilinear paring and the ideal functionality of a commitment scheme was proposed. The proposed protocols can securely realize their ideal functionalities in the hybrid model respectively. Finally, analysis show that these schemes are effective, and it can be more applicable in special situation.

Representation for uncertainty trust of WSN based on lightweight-cloud

2014, 35(2):  9-69. 

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According to the characteristic of qualitative and quantitative uncertainty conversion ability of cloud model, a lightweight cloud model was designed, and the uncertainty representation of direct trust, indirect trust, and recommendation trust in WSN was proposed. The computation cost of lightweight cloud model is quite low so that a single node can build lightweight cloud model independently and evaluate the trust of other nodes to find out the safety hazards in WSN. Simulations in multiple scenarios verify the effectiveness of the proposed method. Simulation results show that this method overcomes the contradiction between the sensitivity and tolerance of traditional trust management framework, furthermore, it’s not only tolerant of abnormal conditions, but also sensitive to multiple attacks.

academic paper

Novel extended cyclic MUSIC algorithm based on uniform circular array

Guo-hong YOU,Tian-shuang QIU,Nan XIA,Ai-min SONG,Zhao-feng WANG

2014, 35(2):  9-15.  doi:10.3969/j.issn.1000-436x.2014.02.002

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By introducing cyclostationary theory into the estimation of direction of signal of arrival, a novel extended cy-clic MUSIC algorithm based on uniform circular array was developed. The proposed method could eliminate both noises and interferences in the same frequency band by exploiting simultaneously the information contained in both cyclic cor-relation matrix and cyclic conjugate correlation matrix of the extended array data vector. It has the ability to select desired signals and ignore interferences from the received data. Simulation results demonstrate that the proposed algorithm has a high DOA estimation accuracy and multi-signal resolution. On the other hand, the proposed method also breaks through the limitation of the classic MUSIC algorithm in which the number of source signal cannot be greater than the number of element in the receiving array.

Spectrum sharing algorithm in multi-channel cognitive radio network based on cooperative game theoretic

2014, 35(2):  10-75. 

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Spectrum sharing problem in multi-channel cognitive radio networks was modeled as a cooperative game. A utility function based on the product of the signal to interference plus noise ratio （SINR） was proposed. The power allocation of secondary users was determined by maximizing the product of the utility function to ensure that the interference power to the primary user is under a certain threshold in each channel. As the problem of maximization the product of the utility function of secondary users was non-convex, it was transformed into an equivalent convex optimization problem by variable alternation. A spectrum sharing algorithm was proposed based on the dual decomposition of the convex optimization problem. Simulation results show that the proposed algorithm achieves an effective compromise between the sum rate and the fairness among the secondary users.

Method of dynamic random network coding in DTN environment

2014, 35(2):  11-86. 

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With the dynamical features of mobility, intermittent connectivity and dynamic topology in delay tolerant network (DTN), the static random network coding methods become difficult to adapt to the applications in DTN environment. For working out this problem, a dynamic random network coding transfer method (DRNC) was proposed. Based on the Markov channel model, it first computed the transmit speeds of every network channel according to the receive data states of nodes, and then constructed the network flow graphic with channel capacities at the source node, calculated and forecasted the current network multicast capacity, after that, the random network coding scenario was extended and tailored according to the multicast capacity to transmit data packages under DTN environment. The simulation results show that, compared with the traditional random network coding method with fixed multicast rate, the dynamic random network coding method has reduced the average latency of data packages and increased the delivery probability.

Speech enhancement based on multi-task sparse representation for dual small microphone arrays

2014, 35(2):  12-94. 

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Speech enhancement algorithms for dual small microphone arrays usually rely on the voice activity detection(VAD), and they may fail in some cases when target speech signal is included in the first frame. A multi-task sparse representation based speech enhancement algorithm was proposed. First, dictionaries for signal and noise were respectively formed via dictionary learning. Then the noise in signals obtain from two microphones was reduced by regularized sparse representation on the over-complete dictionary, while the target speech signals were mostly preserved, hence the speech signals were enhanced. Experimental results from synthetic and real-world data show that the proposed speech enhancement algorithm without VAD works well in all cases no matter speech signal is included in the first frame or not.

Privacy-preserving digital rights management scheme in cloud computing

2014, 35(2):  13-103. 

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In order to meet the needs of digital content and user privacy protection in cloud computing environment, a privacy-preserving digital rights management (DRM) scheme in cloud computing was proposed. The framework of digital content copyright lifecycle protection and user privacy protection in cloud computing was firstly designed, which includes four protocols: system setup, content encryption, license acquisition and content decryption, and then a content encryption key protection and distribution mechanism based on attribute-based encryption and additively homomorphic encryption was proposed, which ensures the security of content encryption key. In addition, the proposed scheme also allows the users to purchase content and acquire license anonymously from cloud service provider, which protects the user privacy and prevents cloud service provider, license server and key server in the cloud from collecting the user’s sensitive information. Compared with existing DRM schemes in cloud computing, the proposed scheme which not only protects the data security and user privacy, but also supports fine-grained access control, and supports online and super-distribution application modes, is more applicable in the copyright protection for cloud computing.

Power allocation of hybrid spectrum sharing based on the spatial location

2014, 35(2):  14-110. 

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Based on the random spatial location of the secondary user, a spatial hybrid spectrum sharing model which combines overlay with underlay was proposed to improve spectrum utilization. Considering the different location of secondary user, the interference received by primary receiver was analyzed and the work regions of the overlay and underlay were deduced under the primary user average interference constraint. The power allocation model was built under the criterion of maximizing the system average (ergodic) capacity. Furthermore, the optimal power allocation scheme was deduced as well as the maximum achievable capacity of the spatial hybrid spectrum sharing system. Analysis and simulation results indicate the hybrid spectrum sharing system has higher capacity than single overlay system.

Identity-based fully homomorphic encryption from learning with error problem

2014, 35(2):  15-117. 

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The fully homomorphic encryption schemes based on learning with errors problem own a great potential value in the cloud computing security. However, the existing schemes share a common flaw of large sized public keys, which may cause inefficiency of such schemes in the key and identity management. An identity-based fully homomorphic encryption scheme was presented. The scheme compromises the merits of both identity-based and fully homomorphic encryption schemes, and it overcomes the above mentioned flaw. The security of the proposed scheme reduces to the hardness of learning with errors problem and the one-wayness of trapdoor function in the random oracle model.

Improved multi-bits flipping algorithm for high-speed LDPC decoding

2014, 35(2):  16-124. 

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In order to improve the decoding speed of the RRWBF algorithm, a multiple-bits selection mechanism was proposed to accelerate the decoding convergence speed of the RRWBF algorithm. However, the RRWBF algorithm with the multiple-bits selection mechanism will appear the bit-repeated flipping, which can impair the decoding performance of the RRWBF algorithm. Hence, a bit-repeated flipping elimination mechanism was proposed to reduce the bit-repeated flipping in the process of the multiple-bits flipping decoding. Simulation results show that the RRWBF algorithm with the multiple-bits selection and the repeated flipping elimination mechanism has a much faster decoding speed at the cost of a little decoding performance loss compared with the RRWBF algorithm.

academic paper

User similarity-based collaborative filtering recommendation algorithm

Hui-gui RONG,Sheng-xu HUO,Chun-hua HU,Jin-xia MO

2014, 35(2):  16-24.  doi:10.3969/j.issn.1000-436x.2014.02.003

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Collaborative filtering recommendation algorithms widely used in e-commerce, recommend interesting content for users from massive data resources by studying their preferences and interests. The focus of similarity and evaluation have been changed when applied to social networks, however, they cause low efficiency and accuracy of the recommen-dation algorithms. User similarity was introduced for redefining the attribute similarity and similarity composition as well as the method of similarity calculating, then a new collaborative filtering recommendation algorithm based on user attrib-utes was designed and some methods for user satisfaction and quality of recommendations were presented. The experi-mental result shows that the new algorithm can effectively improve the accuracy, quality and user satisfaction of recom-mendation system in social networks.

Analysis of spectral efficiency of multiuser MISO downlink based on large-scale antennas

2014, 35(2):  17-136. 

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The spectral efficiency of the downlink of multi-user multiple-input and single-output (MU-MISO) was analyzed in the time-division duplex (TDD) communication systems with large-scale antennas. Assuming that the number of users was fixed and the antenna number (M) of base station (BS) increases without limit, the conclusions through theoretical derivations and analyses were drawn that, when the transmit power of the BS reduces to 1/M of that of BS with single antenna, the system spectral efficiency tends to a constant value with the increase of M if the BS acquires the perfect channel state information (CSI). The adverse effects of the inter-user interferences and the fast fading could also be eliminated through simple pre-processings. Although the multicell system is affected by the pilot contamination, which is the reason why the inter-cell interferences cannot be eliminated, the reduced transmit power makes the system changed from interference-limited to noise-limited. The limit expression of the system spectral efficiency using zero-forcing (ZF) normalized precoding is equal to that using maximum ratio transmission (MRT) normalized precoding. Finally, the lower bound of the spectral efficiency of multi-user downlink applying space time block code was presented and the correctness of the above conclusions was confirmed by the simulation analyses.

Root-MUSIC-based joint TOA and DOA estimation in IR-UWB

2014, 35(2):  18-145. 

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The parameters can be estimated via two-dimensional (2D) multiple signal classification (MUSIC) algorithm, in which the two-dimensional spectral peak searching, however, requires much higher computational complexity. Aiming at this, an algorithm of root-MUSIC-based joint TOA and DOA estimation in IR-UWB system was proposed. After modeling the received signals in the frequency-domain, the algorithm estimated the TOA parameters first, and then the DOA parameters via the difference of the TOA was obtained, thereby the joint TOA and DOA estimation was gained. This algorithm does not need spectral peak searching and can obtain the closed-form solutions of the TOAs and DOAs. Moreover, it can get the parameters paired. In addition, the error variances of the estimated parameters were derived. The simulation results show that the proposed algorithm has much better performance than matrix pencil algorithm, propagator method and estimation of signal parameters via rotational invariance techniques (ESPRIT) algorithm, and has almost the same performance as 2D-MUSIC algorithm, while the complexity of the proposed algorithm has far lower than that of 2D-MUSIC algorithm.

LDPC-coded unitary space-time modulation with low-complexity iterative demodulate-decoding scheme

2014, 35(2):  19-152. 

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A practical low-density parity-check(LDPC) coded unitary space-time modulation (USTM) noncoherent MIMO communication system over Rayleigh flat fading and additive white Gaussian noise (AWGN) channel was constructed, where the LDPC code is selected from IEEE 802.16e Standard and USTM is constructed by the unitary matrix based on the sinc-cosinc function, SC-USTM for short. At the receiver, the maximum a posteriori probability (MAP) demodulating algorithm of the SC-USTM was first designed; for reducing the complexity of MAP demodulator, the dual demodulator was then conceived; for improving the performance, the iterative feedback between the belief propagation (BP) decoder and the MPA demodulator was finally introduced. The simulation test shows that the system of the LDPC coded SC-USTM is superior to the uncoded SC-USTM about 15~17 dB at BER , and this system has very low complexity.

Auto-calibration method and performance analysis for noncircular sources based on instrumental sensors

2014, 35(2):  20-165. 

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An improved direction-finding algorithm for noncircular sources was proposed in the presence of angularly dependent gain and phase errors, which is called NC-ISM based on the fundamental principle of ISM (instrumental sensor method). Through the application of the extended data model of non-circular signals with maximum rate, the proposed algorithm enhances the information utilization leading to advancement of estimation accuracy and twice the number of sources that can be distinguished. The performance study on NC-ISM proved the statistical consistency of the parameter estimation, and a theoretical derivation for the closed-form expression of the mean square error (MSE) of NC-ISM estimation was presented under the influence of modeling errors of instrumental sensors by the first-order analysis. Therefore, the analysis can provide theoretical support for practical applications. The simulation results not only verify the effectiveness of theoretical derivation, but also illustrate that NC-ISM is more robust than ISM with respect to signal-to-noise ratio as well as modeling errors.

Analysis and survey of resource management on modern data center networks

2014, 35(2):  21-181. 

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Data center is the basic facility of Internet and cloud computing. Since network resource is critical resource in data center thorough study and analysis of its management, which can help to improve data center’s performance, save costs and expenses, and is of great significance. However, as the structure characteristic and application mode are profound changing, it brings tremendous challenges to modern data center network resource management. Currently, lots of studies have been made in this field. In order to have an overall perspective of current research, some of the most important aspects were summarized and analyzed, which are automatic address configuration, congestion control, network traffic management and virtualization management. They are also the hotspots in current academe. Based on the comprehensive comparison and analysis, some trends of the future data center network resource management were pointed out in the end.

Improved PSO algorithm based on swarm prematurely degree and nonlinear periodic oscillating strategy

2014, 35(2):  22-189. 

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A novel particle swarm optimization algorithm was proposed, which was adaptive chaos particle swarm optimization algorithm based on swarm premature convergence degree and nonlinear periodic oscillating strategy. The ergodic of chaos was used for initializing the velocities and positions of the particles. The inertia weights were adjusted adaptively according to the swarm’s premature convergence degree and the particles’ fitnesses, and the nonlinear periodic oscillating strategy was used for the learning coefficients, which simulates the decentralization and regroup of the birds when they were foraging. The simulation results on benchmark functions show that the proposed algorithm not only has fast convergent rate and high quality of optimization, but also has good stability.

Related-key impossible differential attack on a lightweight block cipher MIBS

2014, 35(2):  23-193. 

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The strength of MIBS algorithm against the related-key impossible differential attack was examined. MIBS is a lightweight block cipher algorithm. By using the key-expanding properties of MIBS-80 algorithm, a related-key differential feature was presented and a 10-round impossible differential method was constructed by combining special cipher-plaintexts. Based on the impossible differential method, an attack to 14-round MIBS-80 algorithm was given, and the attack complexity both on data and on time were gained. Analysis results indicate the attack to MIBS of 14 rounds MIBS-80 algorithm needs 254 chosen plaintext operations and 256 encrypting computations.

Coordinated beamforming algorithm assisted by receive beamforming vector estimation

2014, 35(2):  24-201. 

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A distributed coordinated beamforming optimization scheme with the assistance of receive beamformer estimation was proposed for downlink cellular wireless communication systems. By sharing a small amount of information among cooperated base stations(BSs), the proposed algorithm estimates the receive vectors of related users at the BSs based on MVDR criterion, which are then utilized to optimize the design of transmit beamforming vectors. The simulation results and analysis show that the proposed distributed scheme can achieve the performance close to that in the centralized scheme with lower overhead and complexity. In addition, a simplified scheme was also proposed which further reduces the system over-head.

Guaranteeing service availability in cloud computing

2014, 35(2):  25-206. 

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A sliding window based resource reservation (SWRR) algorithm was proposed, in which a window is defined as the proportion of the reserved resources among all. The sliding of the window is twofold, adaptively window resizing, and dynamically window content refreshing. SWRR was applied to a large cloud computing platform. Experiments reveal that SWRR can provide high service availability for specific users while taking all users into account by proper resource reservation.

academic paper

Data forwarding mechanism based on dynamical coding nodes managing for intermittent connectivity wireless network

Da-peng WU,Peng-wen LOU,Si-long FAN,Ru-yan WANG

2014, 35(2):  25-32.  doi:10.3969/j.issn.1000-436x.2014.02.004

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The limited network resources can be utilized effectively by the network coding method in intermittent connectivity wireless network, but the number of coding nodes should be dynamically adjusted according to network status. To effectively improving the network resources utilization, a data forwarding mechanism based on dynamically managing coding nodes for intermittent connectivity wireless network was proposed. According to the estimated results of current network status, the optimal number of required coding nodes could be determined with the distributed manner. Further-more, the social property and available resources were considered for coding nodes selecting to achieve reliable data forwarding with the lower overhead. Results show that the connection opportunities between nodes can be exploited adequately by our mechanism; moreover, the utilization of network resources can be improved dramatically.

Novel construction of forward-secure public-key encryption in the standard model

Yang LU,Ji-guo LI

2014, 35(2):  33-39.  doi:10.3969/j.issn.1000-436x.2014.02.005

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All existing provably secure forward-secure public-key encryption schemes in the literature were only proven to be chosen-plaintext secure. A novel forward-secure public-key encryption scheme without random oracles was pro-posed. Under the hardness of the truncated decision q-augmented bilinear Diffie-Hellman exponent problem, the pro-posed scheme was proved to be chosen-ciphertext secure in the standard model. In the proposed scheme, the running time of decryption algorithm and the size of ciphertext are both independent on the total number of the time periods. Com-pared with the previous forward-secure public-key encryption schemes in the literature, the proposed scheme has obvious advantage in security and efficiency.

Preimage and pseudo-collision attacks on 29-step SM3 hash function with padding

Gao-li WANG,Yan-zhao SHEN

2014, 35(2):  40-45.  doi:10.3969/j.issn.1000-436x.2014.02.006

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The security of SM3 hash function was revaluated by using the meet-in-the-middle attack. The preimage and pseudo-collision attack on 29-step SM3 hash function (from the 1-st step) with padding was presented. The time complexities are 2²⁵⁴and 2¹²⁵respectively. Therefore, the 29-step SM3 hash function is not immune to preimage and pseudo-collision attack.

Location prediction algorithm based on movement tendency

Wen LI,Shi-xiong XIA,Feng LIU,Lei ZHANG,Guan YUAN

2014, 35(2):  46-53.  doi:10.3969/j.issn.1000-436x.2014.02.007

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A location prediction algorithm based on movement tendency (LP-MT) was proposed, which not only buils moving object's historical activity model borrowing from Markov thinking, but also added movement tendency as an important reference of location prediction. Besides, each of the historical stay regions was considered as a candidate of future location. According to the characteristics of the future location, algorithm results were divided into prediction locations and recommendation locations. Experiment results on real dataset show LP-MT method can ensure good efficiency and improve the accuracy by 10% compared with the existing algorithms.

Universally composable secure multiparty computation protocol with fairness

You-liang TIAN,Chang-gen PENG,Jian-feng MA,Hui LIN,Kai YANG

2014, 35(2):  54-62.  doi:10.3969/j.issn.1000-436x.2014.02.008

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The fair problem of secure multiparty computation protocol was investigated in the universally composable framework. A fair secure multiparty computation model with ideal functionalities was firstly formulated such as a fair secure multiparty addition computation and a fair secure multiparty multiplicative computation. Next a fair addition computation protocol and a fair multiplicative computation protocol based on the bilinear paring and the ideal functionality of a commitment scheme was proposed. The proposed protocols can securely realize their ideal functionalities in the hybrid model respectively. Finally, analysis show that these schemes are effective, and it can be more applicable in special situation.

Representation for uncertainty trust of WSN based on lightweight-cloud

Xiao-bin XU,Guang-wei ZHANG,Shang-guang WANG,Qi-bo SUN,Fang-chun YANG

2014, 35(2):  63-69.  doi:10.3969/j.issn.1000-436x.2014.02.009

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According to the characteristic of qualitative and quantitative uncertainty conversion ability of cloud model, a lightweight cloud model was designed, and the uncertainty representation of direct trust, indirect trust, and recommenda-tion trust in WSN was proposed. The computation cost of lightweight cloud model is quite low so that a single node can build lightweight cloud model independently and evaluate the trust of other nodes to find out the safety hazards in WSN. Simulations in multiple scenarios verify the effectiveness of the proposed method. Simulation results show that this method overcomes the contradiction between the sensitivity and tolerance of traditional trust management framework, furthermore, it's not only tolerant of abnormal conditions, but also sensitive to multiple attacks.

Spectrum sharing algorithm in multi-channel cognitive radio network based on cooperative game theoretic

Zheng-qiang WANG,Ling-ge JIANG,Chen HE

2014, 35(2):  70-75.  doi:10.3969/j.issn.1000-436x.2014.02.010

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Spectrum sharing problem in multi-channel cognitive radio networks was modeled as a cooperative game. A utility function based on the product of the signal to interference plus noise ratio （SINR） was proposed. The power allocation of secondary users was determined by maximizing the product of the utility function to ensure that the inter-ference power to the primary user is under a certain threshold in each channel. As the problem of maximization the product of the utility function of secondary users was non-convex, it was transformed into an equivalent convex optimization problem by variable alternation. A spectrum sharing algorithm was proposed based on the dual decomposition of the convex optimization problem. Simulation results show that the proposed algorithm achieves an effective compromise between the sum rate and the fairness among the secondary users.

Method of dynamic random network coding in DTN environment

Guang-hong DENG,Wan-hua CAO,Jian ZHANG,Li FENG,Xiong CHENG

2014, 35(2):  76-86.  doi:10.3969/j.issn.1000-436x.2014.02.011

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With the dynamical features of mobility, intermittent connectivity and dynamic topology in delay tolerant net-work (DTN), the static random network coding methods become difficult to adapt to the applications in DTN environ-ment. For working out this problem, a dynamic random network coding transfer method (DRNC) was proposed. Based on the Markov channel model, it first computed the transmit speeds of every network channel according to the receive data states of nodes, and then constructed the network flow graphic with channel capacities at the source node, calculated and forecasted the current network multicast capacity, after that, the random network coding scenario was extended and tailored according to the multicast capacity to transmit data packages under DTN environment. The simulation results show that, compared with the traditional random network coding method with fixed multicast rate, the dynamic random network coding method has reduced the average latency of data packages and increased the delivery probability.

Speech enhancement based on multi-task sparse representation for dual small microphone arrays

Li-chun YANG,Min-chao YE,Yun-tao QIAN

2014, 35(2):  87-94.  doi:10.3969/j.issn.1000-436x.2014.02.012

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Speech enhancement algorithms for dual small microphone arrays usually rely on the voice activity detec-tion(VAD), and they may fail in some cases when target speech signal is included in the first frame. A multi-task sparse representation based speech enhancement algorithm was proposed. First, dictionaries for signal and noise were respec-tively formed via dictionary learning. Then the noise in signals obtain from two microphones was reduced by e2/ ₁e regu-larized sparse representation on the over-complete dictionary, while the target speech signals were mostly preserved, hence the speech signals were enhanced. Experimental results from synthetic and real-world data show that the proposed speech enhancement algorithm without VAD works well in all cases no matter speech signal is included in the first frame or not.

Privacy-preserving digital rights management scheme in cloud computing

Qin-long HUANG,Zhao-feng MA,Jing-yi FU,Yi-xian YANG,Xin-xin NIU

2014, 35(2):  95-103.  doi:10.3969/j.issn.1000-436x.2014.02.013

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In order to meet the needs of digital content and user privacy protection in cloud computing environment, a privacy-preserving digital rights management (DRM) scheme in cloud computing was proposed. The framework of digital content copyright lifecycle protection and user privacy protection in cloud computing was firstly designed, which includes four protocols: system setup, content encryption, license acquisition and content decryption, and then a content encryption key protection and distribution mechanism based on attribute-based encryption and additively homomorphic encryption was proposed, which ensures the security of content encryption key. In addition, the pro-posed scheme also allows the users to purchase content and acquire license anonymously from cloud service provider, which protects the user privacy and prevents cloud service provider, license server and key server in the cloud from collecting the user's sensitive information. Compared with existing DRM schemes in cloud computing, the proposed scheme which not only protects the data security and user privacy, but also supports fine-grained access control, and supports online and super-distribution application modes, is more applicable in the copyright protection for cloud computing.

Power allocation of hybrid spectrum sharing based on the spatial location

Yan CAI,Jing ZHANG,Hong-bo ZHU

2014, 35(2):  104-110.  doi:10.3969/j.issn.1000-436x.2014.02.014

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Based on the random spatial location of the secondary user, a spatial hybrid spectrum sharing model which combines overlay with underlay was proposed to improve spectrum utilization. Considering the different location of sec-ondary user, the interference received by primary receiver was analyzed and the work regions of the overlay and underlay were deduced under the primary user average interference constraint. The power allocation model was built under the criterion of maximizing the system average (ergodic) capacity. Furthermore, the optimal power allocation scheme was deduced as well as the maximum achievable capacity of the spatial hybrid spectrum sharing system. Analysis and simula-tion results indicate the hybrid spectrum sharing system has higher capacity than single overlay system.

Identity-based fully homomorphic encryption from learning with error problem

Yan GUANG,Yue-fei ZHU,Jin-long FEI,Chun-xiang GU,Yong-hui ZHENG

2014, 35(2):  111-117.  doi:10.3969/j.issn.1000-436x.2014.02.015

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The fully homomorphic encryption schemes based on learning with errors problem own a great potential value in the cloud computing security. However, the existing schemes share a common flaw of large sized public keys, which may cause inefficiency of such schemes in the key and identity management. An identity-based fully homomorphic en-cryption scheme was presented. The scheme compromises the merits of both identity-based and fully homomorphic en-cryption schemes, and it overcomes the above mentioned flaw. The security of the proposed scheme reduces to the hard-ness of learning with errors problem and the one-wayness of trapdoor function in the random oracle model.

Analysis of spectral efficiency of multiuser MISO downlink based on large-scale antennas

Ju-fang LI,Rui ZHAO,Bin JIANG,Yong-ming HUANG,Lv-xi YANG,Hai ZHANG

2014, 35(2):  125-136.  doi:10.3969/j.issn.1000-436x.2014.02.017

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The spectral efficiency of the downlink of multi-user multiple-input and single-output (MU-MISO) was ana-lyzed in the time-division duplex (TDD) communication systems with large-scale antennas. Assuming that the number of users was fixed and the antenna number (M) of base station (BS) increases without limit, the conclusions through theo-retical derivations and analyses were drawn that, when the transmit power of the BS reduces to 1/M of that of BS with single antenna, the system spectral efficiency tends to a constant value with the increase of M if the BS acquires the per-fect channel state information (CSI). The adverse effects of the inter-user interferences and the fast fading could also be eliminated through simple pre-processings. Although the multicell system is affected by the pilot contamination, which is the reason why the inter-cell interferences cannot be eliminated, the reduced transmit power makes the system changed from interference-limited to noise-limited. The limit expression of the system spectral efficiency using zero-forcing (ZF) normalized precoding is equal to that using maximum ratio transmission (MRT) normalized precoding. Finally, the lower bound of the spectral efficiency of multi-user downlink applying space time block code was presented and the correctness of the above conclusions was confirmed by the simulation analyses.

Root-MUSIC-based joint TOA and DOA estimation in IR-UWB

Fang-qiu WANG,Xiao-fei ZHANG,Fei WANG

2014, 35(2):  137-145.  doi:10.3969/j.issn.1000-436x.2014.02.018

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The parameters can be estimated via two-dimensional (2D) multiple signal classification (MUSIC) algorithm, in which the two-dimensional spectral peak searching, however, requires much higher computational complexity. Aiming at this, an algorithm of root-MUSIC-based joint TOA and DOA estimation in IR-UWB system was proposed. After mod-eling the received signals in the frequency-domain, the algorithm estimated the TOA parameters first, and then the DOA parameters via the difference of the TOA was obtained, thereby the joint TOA and DOA estimation was gained. This al-gorithm does not need spectral peak searching and can obtain the closed-form solutions of the TOAs and DOAs. More-over, it can get the parameters paired. In addition, the error variances of the estimated parameters were derived. The simulation results show that the proposed algorithm has much better performance than matrix pencil algorithm, propaga-tor method and estimation of signal parameters via rotational invariance techniques (ESPRIT) algorithm, and has almost the same performance as 2D-MUSIC algorithm, while the complexity of the proposed algorithm has far lower than that of 2D-MUSIC algorithm.

LDPC-coded unitary space-time modulation with low-complexity iterative demodulate-decoding scheme

Li-jiao WANG,Lin ZHANG,Ling-ling YANG,Li PENG,Da-wei FU

2014, 35(2):  146-152.  doi:10.3969/j.issn.1000-436x.2014.02.019

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A practical low-density parity-check(LDPC) coded unitary space-time modulation (USTM) noncoherent MIMO communication system over Rayleigh flat fading and additive white Gaussian noise (AWGN) channel was con-structed, where the LDPC code is selected from IEEE 802.16e Standard and USTM is constructed by the unitary matrix based on the sinc-cosinc function, SC-USTM for short. At the receiver, the maximum a posteriori probability (MAP) de-modulating algorithm of the SC-USTM was first designed; for reducing the complexity of MAP demodulator, the dual demodulator was then conceived; for improving the performance, the iterative feedback between the belief propagation (BP) decoder and the MPA demodulator was finally introduced. The simulation test shows that the system of the LDPC coded SC-USTM is superior to the uncoded SC-USTM about 15～17 dB at BER10^?5, and this system has very low complexity.

Auto-calibration method and performance analysis for noncircular sources based on instrumental sensors

Jie-xin YIN,Ying WU,Ding WANG

2014, 35(2):  153-165.  doi:10.3969/j.issn.1000-436x.2014.02.020

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An improved direction-finding algorithm for noncircular sources was proposed in the presence of angularly dependent gain and phase errors, which is called NC-ISM based on the fundamental principle of ISM (instrumental sen-sor method). Through the application of the extended data model of non-circular signals with maximum rate, the pro-posed algorithm enhances the information utilization leading to advancement of estimation accuracy and twice the num-ber of sources that can be distinguished. The performance study on NC-ISM proved the statistical consistency of the pa-rameter estimation, and a theoretical derivation for the closed-form expression of the mean square error (MSE) of NC-ISM estimation was presented under the influence of modeling errors of instrumental sensors by the first-order analysis. Therefore, the analysis can provide theoretical support for practical applications. The simulation results not only verify the effectiveness of theoretical derivation, but also illustrate that NC-ISM is more robust than ISM with respect to signal-to-noise ratio as well as modeling errors.

Overview

Analysis and survey of resource management on modern data center networks

ENGGang D,Zheng-hu GONG,Hong WANG,Lin CHEN,Zhi-hong LIU

2014, 35(2):  166-181.  doi:10.3969/j.issn.1000-436x.2014.02.021

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Data center is the basic facility of Internet and cloud computing. Since network resource is critical resource in data center thorough study and analysis of its management, which can help to improve data center's performance, save costs and expenses, and is of great significance. However, as the structure characteristic and application mode are pro-found changing, it brings tremendous challenges to modern data center network resource management. Currently, lots of studies have been made in this field. In order to have an overall perspective of current research, some of the most impor-tant aspects were summarized and analyzed, which are automatic address configuration, congestion control, network traf-fic management and virtualization management. They are also the hotspots in current academe. Based on the comprehen-sive comparison and analysis, some trends of the future data center network resource management were pointed out in the end.

Academic communication

Improved PSO algorithm based on swarm prematurely degree and nonlinear periodic oscillating strategy

Xi-hua ZHU,Ying-hui LI,Ning LI,Bing-kui FAN

2014, 35(2):  182-189.  doi:10.3969/j.issn.1000-436x.2014.02.022

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A novel particle swarm optimization algorithm was proposed, which was adaptive chaos particle swarm opti-mization algorithm based on swarm premature convergence degree and nonlinear periodic oscillating strategy. The er-godic of chaos was used for initializing the velocities and positions of the particles. The inertia weights were adjusted adaptively according to the swarm's premature convergence degree and the particles' fitnesses, and the nonlinear periodic oscillating strategy was used for the learning coefficients, which simulates the decentralization and regroup of the birds when they were foraging. The simulation results on benchmark functions show that the proposed algorithm not only has fast convergent rate and high quality of optimization, but also has good stability.

Related-key impossible differential attack on a lightweight block cipher MIBS

Ping CHEN,Fu-cheng LIAO,Hong-ru WEI

2014, 35(2):  190-193.  doi:10.3969/j.issn.1000-436x.2014.02.023

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The strength of MIBS algorithm against the related-key impossible differential attack was examined. MIBS is a lightweight block cipher algorithm. By using the key-expanding properties of MIBS-80 algorithm, a related-key differ-ential feature was presented and a 10-round impossible differential method was constructed by combining special ci-pher-plaintexts. Based on the impossible differential method, an attack to 14-round MIBS-80 algorithm was given, and the attack complexity both on data and on time were gained. Analysis results indicate the attack to MIBS of 14 rounds MIBS-80 algorithm needs 2⁵⁴chosen plaintext operations and 2⁵⁶encrypting computations.

Coordinated beamforming algorithm assisted by receive beamforming vector estimation

Ying HUANG,Gang-ming LV,Shi-hua ZHU

2014, 35(2):  194-201.  doi:10.3969/j.issn.1000-436x.2014.02.024

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A distributed coordinated beamforming optimization scheme with the assistance of receive beamformer esti-mation was proposed for downlink cellular wireless communication systems. By sharing a small amount of information among cooperated base stations(BSs), the proposed algorithm estimates the receive vectors of related users at the BSs based on MVDR criterion, which are then utilized to optimize the design of transmit beamforming vectors. The simula-tion results and analysis show that the proposed distributed scheme can achieve the performance close to that in the cen-tralized scheme with lower overhead and complexity. In addition, a simplified scheme was also proposed which further reduces the system overhead.

Guaranteeing service availability in cloud computing

Shi-jun SHEN,Xin-ran LIU,Hong ZHANG,Chun-ge ZHU

2014, 35(2):  202-206.  doi:10.3969/j.issn.1000-436x.2014.02.025

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A sliding window based resource reservation (SWRR) algorithm was proposed, in which a window is defined as the proportion of the reserved resources among all. The sliding of the window is twofold, adaptively window resizing, and dynamically window content refreshing. SWRR was applied to a large cloud computing platform. Experiments reveal that SWRR can provide high service availability for specific users while taking all users into account by proper resource reservation.