- EI核心期刊
In order to achieve multiple-image simultaneous encryption for an efficient transmission of secured data, the paper employs the position multiplexing and records multiple images into a hologram by computer generated holography based on the optical scanning holography (OSH). The decryption is modeled into an inverse problem. This paper utilizes a regularization in solving the inverse problem so as to extract images simultaneously with edge preserved. Numerical experiments demonstrate the feasibility of the algorithm and the robustness to image destruction. The subsequent analysis of the experiments investigates the image quality and security of the algorithm.
An Optimal Equalization and Precoding Joint Optimization Algorithm in Dual Hop Relay System Abstract: A novel detection and precoding joint optimization algorithm was proposed in dual hop relay communication systems,this solution combines the detection for the first phase and precoding for the second phase in relay system, therefore the joint optimization can be equaled to the unique optimization for the product matrix of detection and precoding, and avoid the non convex optimization for commonly joint optimization, and also avoid the non-convergence problems in iterating process,and compared with iterative optimization, the complexity burden of this algorithm is greatly reduced, and from simulation results the performance is only a little degraded, therefore, when complexity and performance is considered, this algorithm reached a better compromise
Finite element model of band brake transient temperature field is built considering heat transmission theory and drum brake structural features. The randomness of physical parameters and boundary conditions of heat transfer was considered, each parameter and initial boundary conditions are regarded as interval parameters. With the finite element and time difference methods, the perturbation formulas of the upper and lower bounds of responses of temperature fields with unknown-but-bounded parameters were derived via the combination of interval analysis and the traditional finite element method. and then the range of temperature field response of the drum brake is obtained. The results show the method of the paper is feasibility and effectiveness
In this paper, a new type of hybrid particle swarm optimization (PSO) algorithm is presented. The new algorithm is named as gbest optimization based particle swarm optimization algorithm (GOPSO). Comparing with the conventional PSO (CPSO) algorithm, GOPSO shows faster convergence to the global optima, less generation number needed to obtain an acceptable result, lower probability to lock into sub-optima, and easy implementation in the real-world applications. We use GOPSO as control algorithm to implement adaptive compensation system for polarization mode dispersion (PMD) in high-speed optical fiber communication system and the performance of GOPSO shows much better performance than that of CPSO.
According to the characteristics of virtual network resource allocation among competitive environment of multiple Infrastructure Providers (InP) and multiple Service Providers (SP), auction based virtual network resource allocation mechanism (ABVNRAM) are presented from service management aspect, and the validity of ABVNRAM is proved. The experimental results show that ABVNRAM can complete multiple InPs and SPs resource allocation and pricing each time. Greater social welfare is produced by ABVNRAM than V–MART and ABVNRAM without bargaining.
This paper proposes a space division multiplexing based joint transmit-receive spectrum sharing method in cognitive radio networks (CRN). By exploiting spatial correlation features between cognitive transmission and interference among different systems, appropriate primary system and its channel could be selected under the condition that no idle spectrum resource is available. Consequently, spectrum sharing is carried out using space division multiplexing. Analysis and simulation results show that compared with the method implemented only at cognitive base station (CBS) and exhaustive searching, the proposed scheme could achieve near-optimal system throughput performance with reduced complexity.
According to the principles of quantum ranging, the time of arrival (TOA) can be measured in a much higher accuracy by utilizing a quantum pulse which includes entangled-squeezed photons, than that by utilizing a classical electromagnetic pulse. However, the maximal entangled quantum pulse has a very poor robustness of measurement in a non-ideal transmission channel, since the loss of a single photon will make the TOAs of other photons to be totally useless. A partially entangled quantum pulse will have a better robustness of measurement, whereas its measurement accuracy would be reduced with the decrease of entanglement. In order to solve problem between the accuracy and the robustness of the measurement, a new structure of quantum entanglement utilizing grouped and squeezed photons is proposed in this paper. Also, the relationship between the degree of entanglement, quantum transmission efficiency, and the measurement precision is deduced in detail to analyze the performance of this kind of quantum entanglement structure. Finally, considering the specific quantum transmission efficiency, the maximum accuracy gain of the measurement is obtained through the selection of a proper quantum entangle structure, the number of photons to be squeezed and the optimal degree of entanglement.
Recently, Luo et al. used their signcryption-based concurrent signature scheme to design a fair exchange protocol, and they claimed that their schemes are secure. Through security analysis, their signcryption-based concurrent signature is insecure. If the receiver has a valid ambiguous signature of the signer, without the signer’s keystone and secret key, he can obtain the signer’s message and forge an ambiguous signature on arbitrary message on behalf of the signer easily. So, the fair exchange protocol is insecure. Then, an improved signcrytion-base concurrent signature was presented which overcame the flaw of the previous scheme, which ensured the security of the fair exchange protocol.
In the composition of Web Services, if the reuse is extended to a courser granularity than Web Services, that is, in BPEL processes’ level, and some process templates are generated, then, the developers can directly construct new business processes based on these templates, as a result, the efficiency and accuracy of the development of BPEL processes are improved. To achieve this, a method is proposed: converting the generation problem of process templates to the discovering problem of trees’ frequent patterns. Firstly, a whole BPEL process is modeled as a rooted unordered tree; then, frequent induced sub-trees are mined out based on TMG (Tree Model Guided); finally, frequent sub-trees are mapped back to BPEL process templates. A tool named ROY-BPELTool is implemented in java for generating process templates for BPEL, and BPEL processes of a real multimedia conference system run on it. Experiment results show the method’s validity.
A Characteristic polynomial algorithm for computation of Chebyshev polynomial over finite field is modified to achieve faster execution speed. First, the Montgomery modular multiplication is introduced to replace the classical modular multiplication, and to reduce the average time cost on a multiplication, by avoiding the division operation in modular arithmetic. Second, the procedure of Montgomery modular square algorithm is modified to reduce the required number of single-precision multiplications. The simulation results show that the modified algorithm is faster than the original one.
To decrease the time complexity of the attribute reduction algorithm based on information entropy, the concurrent processing of ants colony optimization is introduced into partition. This process based on the judgement of attribute reduction between partition and information entropy. In this searching process the strategy of state transfer and pheromone update reflect the difference of the attribute’s importance in order to optimize the results. By the analysis of this algorithm’s complexity and the example’s application,it is shown that the algorithm can avoid the blindness of the ant colony searching and reduce the size of the iteration to obtain reduction faster.This is more suitable for large data base.
Different P2P live streaming systems represent different design conceptions and present obviously different characteristics. Currently, most studies on P2P living streaming systems are based on PPLive, while PPStream is hardly known to researchers because its protocols are not open to public. The contributions of this paper are: (1) peers’ buffer structure and sharing mechanism in PPStream live system are figured out in this paper. It is found that peers have jumping sharing window in PPStream which is different from PPLive with sliding sharing window. In PPStream, video chunks are classified into different windows (or phases). Peers downloading chunks in the same phase can share data with each other; (2) authors use a window jumping model to analyze the impact of buffer structure and sharing mechanism on the reciprocal relation between peers. It is found that the sharing mechanism in PPStream can result in peers’ phase fluctuation; (3) based on the features of phase fluctuation, authors develop a predicting model to describe the user population of different phases. Numerical evaluation and system simulation both show that the model can well reflect the fact that the contention on bandwidth resources contributes to the peers’ phase fluctuation. It can bring insights to the work of further improving the bandwidth assignment strategy and peers’ playback quality.
A Web Usage Mining algorithm named Closed Frequent Itemsets Hierarchical Clustering based on Quantities (CFIHCQ) is proposed. The algorithm first obtains Closed Frequent Itemsets with network user Web access data. Then it initial clusters with Closed Frequent Itemsets and points users in to the only cluster using scoring method. After that, it construct cluster tree using cluster labels. User access vectors are used to divide sub-clusters in cluster tree. Finally the cluster tree is pruned. Experimental results indicate CFIHCQ has many advantages such as accurate predicating network user Web access behavior, real-time mining in huge data set, and easy-browse result with tree structure.
Based on the analysis of the interference between the Base Station(BS) and wireless microphones(WMs) and the interference between Consumer Premise Equipments(CPEs) and WMs in Wireless Regional Area Network(WRAN), a new WRAN-WM coexistence model is established. A mathematical model of subchannel allocation in a single cell of WRAN is established which target is maximize the data transmission rate for downlink of system. Modeling the subchannel allocation as finding maximum matching graph of the bipartite graph, we get the optimal solution to employs Hungarian algorithm based on the graph theory to solve the problem which is a mixed-integer nonlinear programming. The simulation results show that the proposed scheme is very effective.
The traditional adaptive modulation and coding (AMC) choose transmission rate adaptively only according to channel state. In order to achieve better performance of the network, an improved AMC considered both the channel state of the physical layer and the buffer queue length of the data link layer is developed in this paper, which can choose the transmission rate self-adaptively according to the buffer queue length of the link layer and the channel state. Compared to the traditional AMC method, the improved AMC can achieve a better network performance. Based on the three-node multiple hops network model, it gets the largest throughput which satisfy the delay requirement through the joint distribution algorithm of power and bandwidth. Simulation results show that the new method can improve the throughput performance of the network which meets the system delay requirements.
Based on a novel palletizing robot, its kinematic equations was established using D-H method. When considering some constraint conditions, its kinematics equations are solved by using numerical methods and its three-dimensional workspace maps and coordinate plane projection maps are derived. On this basis, the concept of influence coefficient on robot workspace is brought forward and defined. Finally, the influence coefficients curves of the length and rotation angle of links are obtained and quantitatively analyzed in detail，which provided a basis for its structural optimization and design from kinematic view.
Energy saved is a core index for reflecting environment performance of enterprises, since it is the direct result of energy saving or emission reduction. First put forward segment models for total energy saved of productions of telecom operators, divide energy saving into technological energy saving made up of technical reform and progress, managing energy saving made up of control measures and marketing, and lastly energy saving of product mix variety. And design algorithms for different segments of energy saved. Determine the proper coefficients of total energy saved of productions and conclude the 4-stage low-carbon development model of China telecom operators.
An enhanced channel estimation method is proposed for the long term evolution (LTE) uplink single carrier-frequency division multiple access (SC-FDMA) systems with multi-user. Since the every user pilot symbol only hold fractional bandwidth, which leads to the length of the estimated subchannel vector of the every pilot symbol used to performing the noise reduction is too short, so the estimated channel vectors of the two pilot symbols by LS algorithm are sorted according to the time-frequency correlation at first, which aims to increasing the length of the pilot subchannel processed in the transform domain. And then an orthogonal transform matrix is constructed to reducing noise of the sorted channel in the transform domain. Based on the orthogonal transform matrix, a channel estimation algorithm with high accuracy is proposed. Simulation results show that the mean square error (MSE) of the proposed method is about one tenth of that of the LS method.
A routing algorithm based on time series prediction for delay tolerant network is proposed. In this paper the weight moving average method which is one of time series prediction methods is improved, and the history connected information of nodes is used to predict the connection state in the future. Furthermore, the routing criterion is to ensure that messages reach the target node as much as possible soon. Any network connection information does not need, and the routing path can change followed with the change of network topology so that new routing table can be update immediately. The proposed algorithm can avoid the shortcoming of existing algorithm which needs amount of prior knowledge of routing information. So the proposed algorithm has strong applicability. The simulation experiment results have showed that the proposed algorithm compared with MED and MEED have higher delivery ratio and lower average time in different bandwidth and buffer size.
Based on the support vector machine method, a motion control algorithm for the spherical robot is introduced. Using this algorithm, the human control strategy can be represented to achieve the precise position control without knowing the robot dynamics model. The realization of the algorithm is introduced. The repeated experiments results show that the positioning control for the spherical robot can be achieved precisely by this algorithm.
The kinemics analysis of a kind of bicycle robot is presented in the paper. And the function relationship among robot rolling angle, drive speed and steering angle could be expressed with a three-dimensional surface in an X-Y-Z coordinate. The lower bound of the drive speed which is needed to balance the robot is presented theoretically. The goal of balancing the robot could be achieved by the means of tuning the steering angle in condition of the drive speed is higher than the critical value. The computer simulation results show that the drive speed belongs to the interval which has the critical value as the lower bound when the robot has different rolling angle and steering angle. Computer simulation verified the validity of the kinemics model. The real bicycle robot control experiments were performed based on the kinemics analysis. It is found that the theoretical result is consistent with the experiment data by comparing them. Then the validity of the kinemics analysis is testified by experiments.
A broadband anti-interference directional mono-cone antenna is designed in order to avoid electromagnetic interference sources in wireless communication. Omni-directional cone antenna is made improvement by adding shorted stub to realize mono-cone antenna directionality in H-plane. New method is different from general methods such as using array antenna or adding reflector, which will not increase the size of the antenna. The 3dB beamwidth in H-plane is wide and the return loss is less than -10dB within the frequency range of 1.7GHz ~ 6.0GHz of this antenna. The acceptable agreement of measured and simulated results shows that this kind of antenna has perfect input impedance and pattern properties．
Grid computing and Peer-to-Peer( P2P) study up on the problem of share for large-scale resource, P2P provides a effective and extensible solution for resource discovery in large-scale distributed environment ,this paper presents an a hybrid architecture of grid and P2P with three-layer for resource management, set up catalogue-tree for resource attribute with the form of group, promotes the efficiency for resource discovery, designs a grid scheduling model which is layered to deal with the problem of optimization scheduling and load balance, on this condition then put forward a grid scheduling algorithm integrating P2P, and achieves the optimal matching between grid tasks and resources. Finally it validates the validity of the algorithm and the feasibility of the architecture by the theory analysis and experiment experiments.
In order to improve the performance of variable step-size LMS-type algorithm based on Sigmoid function (SVS-LMS) for case of Gaussian noise and impulsive noise interference,firstly, the method of updating step-size controlled by instantaneous error’s power is replaced by adjusting step-size under the control of time-averaged estimate of error autocorrelation. Then, HB weighted method is introduced into the algorithm to restrain fake peaks of adaptive filter’s coefficient vector and normalized process is introduced to obtain a greater dynamic range of input signal. Simulation results of tracking time-varying delay show that, comparing to SVS-LMS and another refrained SVS-LMS algorithm being of fixed parameters, the algorithm and its HB weighted method can achieve superior MSE performance.
Current virtual assembly technology has been gradually improved in either hardware system construction or software platform researching. Study in human-computer interaction using virtual assembly technology would be a necessary means to level-up the practicability of virtual assembly. The paper proposes an assembly-context granular model pertinent to the conception of assembly context, and presents a granular perception algorithm of assembly context based on quotient theory and similarity theory. It also shows in the paper that this algorithm is practical through an instance analysis of shafting assembly.
There is a contradiction between miniature aperture size and high accuracy in the interferometer Direction-finding machine. For solving this problem, a novel antenna array and Direction-finding algorithm based on it are proposed. The improvement of the new method and the effect of all kinds of errors are thoroughly analyzed and relevant solutions are discussed. A proposed relevant compensate method can counteract all system errors of the whole Direction-finding machine in theory. The advantage and feasibility of the new algorithm are demonstrated in the Matlab.
For the problem of nonlinear estimation with single IRST in target tracking, a new algorithm of Multihypothesis Cartesian Gauss-Hermite filter is presented. In order to decrease the influence of non-observability of distance, based on Gauss-Hermite filter, multihypothesis of distance is adopted to operate collateral filter. First, at the initial time, the measurement interval of IRST is divided into a number of subintervals, each of which represents a hypothesis responding to the true range of the object. For each hypothesis, Gauss-Hermite filter is implemented with the common measurement. The probability of each subinterval is calculated recursively according to Bayes’ criteria. Finally, the weighted estimation of state and covariance is calculated for sum respectively to get the final eastimation.. Simulation results show that the accuracy of filter in this paper is better than the original Gauss-Hermite filter and EKF ,for the reason that Gauss-Hermite filter avoids the calculation of Jacobian matrix and the multihypothesis of distance decreases uncertainty.