- EI核心期刊
The rapid development of nano and biology technologies pave the way to the research of molecular communication within the body area. The article surveys the recent advents of the bacteria-based molecular communication, in which the bacteria conjugation and bacteria paracrine transmission mechanisms are elaborated, and the related experiment and simulation are presented. Accordingly, the body-area nano-network based on bacteria molecular communication is discussed, and the corresponding relay networking technology is presented. Finally, the future open issues and challenges are discussed.
Based on ad-hoc on-demand distance vector routing protocol, combined with the features of formation communication system, the black hole problem was analyzed and an ad-hoc on-demand distance vector routing method with security mechanism was proposed to solve the problem. Combining the specific routing protocol, the proposal not only focuses on the characteristics of the algorithm, but takes account of the specific features of the application, making it simple and easy to implement. Simulations show that in addition to guaranteethe packets delivery ratio, the extra control overhead is able to withstand in the system range as well.
As a fundamental spatial relation, the direction relations can describe position information between objects, which has been an important issue for spatial knowledge processing. Conventional researches mainly concern over the relations of simple objects, which restrict spatial relation modeling in further practical and theoretical research. The article focuses on the representation and reasoning models of direction relations of uncertain regions with qualitative methods. Firstly, an uncertain boundary was described using broad boundary model, and the direction relations between uncertain regions were represented with the combinations of basic cardinal direction relations. Moreover, through the representations, the direction relation constraints and satisfaction problem constraints or uncertain regions were defined. And a consistency checking algorithm was proposed for reasoning about the direction relations between uncertain regions, and the computational complexity of this algorithm was also analyzed.
In order to solve the problems which may be arised when the routing policy of control plane is updated in in-band mode, an update mechanism based on the destination oriented routing was proposed. The mechanism divides the update policy into subclasses based on the different destinations, and also separates the uplink routing from downlink routing based on the destination. A unified update algorithm was presented for the updating of both uplink and downlink of controlling traffic. Experiment shows that the proposed mechanism shows more efficient both in the computation time and in updating time, but some extra flow entries may be needed.
The recommendation performance of collaborative filtering is restricted by data sparsity. To solve this problem, the factor of user influence was thereafter defined according to the number of ratings to measure the relationship while calculating the similarity between users. Then, the influential user group was introduced according to the rating quality. On this basis, the chosen influential neighbor can work on the process of recommendations via combining the number of user ratings with the rating quality. Experiments show that the proposed method can significantly improve the recommendation performance.
To solve the problem that the traffic flow dynamically changes in Internet protocol (IP) network, a new energy saving algorithm based on pre-configured multiple topologies (ESPMT) was proposed. In the ESPMT algorithm, firstly, according to the daily traffic flow, each day is divided into multiple time slices, secondly, the energy-saving sub-topology is designed by utilizing neighboring region search for each single time slice. To achieve the purpose of energy saving, the traffic flows are concentrated on some links. The links without traffic are powered off in IP networks.
For multi-channel duty-cycled wireless sensor networks, the minimum delay broadcast problem was proved to be NP-hard. Two new concepts of candidate active conflict graph and feasible active conflict graph were presented. A Low delay broadcast algorithm called efficient broadcast algorithm was proposed based on these two new concepts. Analysis shows that this algorithm has a small approximation ratio. Simulation shows at the same time that efficient broadcast algorithm improves the broadcast delay efficiently compared with the existing work.
The autonomous recognition mechanism on survivability is still in the ascendant, and the cognition is the realization premise of the recognition. A cognitive evaluation mechanism for survivable system was proposed based on the shortest K-path algorithm. Firstly, a framework structure of the cognitive evaluation for survivable system is established, the cognitive state transfer matrix and cognitive evaluation index are given. Then, a quantitative model for the cognitive survivability of the system is made. Finally, a cognitive performance simulation experiment in some network security situation awareness system is carried out under DoS attacks. Experiment shows that the presented method faithfully reflects the dynamic evolution of cognitive performance under different attack parameters, analyses the survival threat of the system and validates the effectiveness of the proposed method.
This article puts forward a combined chirp signal time synchronization(CCS-Sync) algorithm. In the physical layer, it uses a preamble structure combined with chirp signals to estimate the Doppler scaling factor. Furthermore, the author proposes a message exchange mechanism composed of two phases. In the phase of coarse synchronization, the reference node broadcasts messages to synchronize the ordinary nodes. Based on the first phase, it uses twice linear regression method to estimate the clock skew and offset. With this algorithm, it successfully uses the effect of Doppler between mobility nodes to reduce the synchronization error. The effectiveness of CCS-Sync is validated by the simulation.
A circular structure based target information collection algorithm was presented, which constructs a dynamic circles structure by selecting backbone nodes. The algorithm further constructs the dependencies between backbone nodes and normal nodes to form the backbone path. The target location information was processed and forwarded in networks. Finally, the performance of the proposed algorithm was analyzed.
Crater is important for analyzing the relative dating of planetary and lunar surfaces. For the complex terrains in remote sensing images, a robust blocked principal components analysis (RPCA) approach was proposed to automatically detect crater candidate regions. An alternating direction multipliers algorithm was presented for RPCA based on the blocked planetary images. The background is modeled as a low-rank matrix, and the salient regions map is represented by structure sparse parts that contain potential craters. The crater candidates are obtained by mathematical morphological operations for the saliency regions map, they are precisely distinguished from falsely detected ones through a sparse representation classifier in feature space. Experiments on the images from Mars and Moon demonstrate show that the accuracy rate of crater recognition can reach up to 91.7% by effectively eliminating the effects of background and illumination.
Aiming at the problem of current false data filtering strategies that cannot prevent legitimate packets from discarded by the malicious nodes selectively, an en-route filtering strategy was put forward against selectively discarding packets. In this strategy, each node keeps its one-hop and two-hop neighbor nodes' identifications as well as one-way chain keys. Moreover, what the forwarded packets attached is the latest one-way chain keys of L nodes, not the message authentication codes in traditional en-route filtering strategies. Additionally, this strategy uses the stepwise certification to submit data packets by monitoring the communications between common neighbor nodes. Experiment shows that the strategy not only can efficiently filter false data, but also can prevent malicious nodes from selectively discarding packets.
A multiband impulse radio ultra wideband (MIR UWB) communication system based on parallel combinatory pulses was proposed, in which the flexible selection of transmission pulses and subbands can be realized by using r-combinatory data mapping algorithm. The system model was given and the bit error rate (BER) performance was simulated and analyzed. It is shown that BER performance of the proposed system is better than that of the traditional system under the condition of large signal-to-noise ratio, and different transmission data rate can be obtained as well.
The decoding complexity of traditional type of Turbo-overlapped code division multiplexing (OVCDM) increases exponentially with the code rate. To solve this problem, a new Turbo-OVCDM coding and decoding approach was proposed. The maximum sum-rate achieving strategy in Gaussian multiple access channels was used to construct point-to-point coding scheme. Superposition of two or more Turbo-OVCDM codes and serial interference cancellation were applied for coding and decoding respectively. Numerical results demonstrate the feasibility of the proposed approach.
In green optical networks, the transmission time-slot allocation strategy and routing algorithm have a greatly impact on the transmission energy consumption. Aiming at the transmission energy consumption problem, a bandwidth-variable energy efficient scheduling (BVEES) algorithm based on flexible-time scheduled traffic was proposed. By constructing a weight matrix, BVEES calculates the selected times of different path candidates in different slots. Based on the idea of greedy algorithm, BVEES selects the transmission paths and time slots with the minimum transmission energy consumption. In addition, a bandwidth adjustment strategy, which can adjust transmission bandwidth according to the available bandwidth in different slots, was designed for BVEES to minimize the number of lightpaths in optical networks. Simulations show that the BVEES can effectively reduce the transmission energy consumption and the blocking probability.
In the existing multi-secret sharing schemes mainly depending ondealer selections, the polynomial coefficients constructs the polynomial and takes the value ofpolynomial function as shadows of secrets, however, the semi-honest dealer may leak information of secrets by changing the polynomial coefficients. In order to solve the problem by semi-honest dealer, the article presented a new leakage-resilient verifiable multi-secret sharing scheme The problem of leakage secret information hiddens in that the polynomial coefficients are selected and constructed by all of participants. Comparison with existing schemes which also achieve verifiable multi-secret sharing, the scheme can still work well even when the dealer leaks some secret information.It has better efficiency in terms of computation overhead.
A low input DC/DC converter and power manager in 0.18 μm CMOS process was presented. The proposed converter can work with the input voltage as low as 25 mV. Four logic controlled outputs provide the best voltage for various applications to accommodate low-power design requirements. Reserve energy on the storage capacitor CSTORE provides power when the input voltage source is unavailable. Simulation shows that the overall efficiency is about 64% with 300 μA load current. This work provides a complete power management solution for wireless sensing and data acquisition.
For the shortcoming that the excessive number of robot movement is required during the hand-eye calibration, an improved self-calibration method to hand-eye relation of robot based on a single feature point was proposed. The decoupling operation for hand-eye relation matrix was introduced, and also the hand-eye rotation matrix and translation vector were calibrated respectively. In the calibration process, the feature point position is not necessary to be calculated, but and the manipulator end effector is needed also to perform more than five times translational motions and two times rotation motions. Calibration experiment and error analysis verify that the method can meet the demand for industrial robot hand-eye vision measurement.
A type of data gathering method based on one mobile sink for balanced energy consumption in sensor networks (DGBEC) was proposed. Coordinates of each traverse point was calculated by sensing coverage model, and the path with fixed length for mobile sink was also built. Simulations show that DGBEC performs very well in energy consumption balance than virtual nodes priority (VNP) and rendezvous points finding with a utility-based greedy heuristic (RP-UG) methods.
With development of cloud computing and big data, the energy consumption of data center becomes more and more serious. It is necessary to establish a precise model of energy consumption for the computing node of the data center. In the most previous studies, linear system utilization is taken to establish the models of energy consumption. In order to solve the accuracy insufficient of linear model, a model of energy consumption based on the segmented CPU utilization was proposed when considering the memory and the hard drive at the same time. In the experiment, the inner relationship between the energy consumption and the CPU was found, and a formula of the potential influence of the components was proposed, and the accuracy of the model is verified in both single environment and parallel environment.
A forgery attack on Fan Aiwan et al's certificateless signature scheme was presented. It is found that the strong type I adversary could forge any user's valid signature on any message. The reason of this problem is that the random number selected in the signature generation phase is not associated with the message M. To improve the original scheme's security, the improved schemes in which the random number selected in the signature generation phase is bound to the hash function value of message M was proposed. The scheme proposed can resist both super type Ⅰ and type Ⅱ adversary, and it only needs one scalar multiplication in signature generation phase and four scalar multiplications in signature verification phase; the other schemes proposed can resist strong type Ⅰ and super type Ⅱ adversary and are secure against the attacker in the real world. In addition, they only need one scalar multiplication in signature generation phase, and three scalar multiplications in signature verification phase. The improved schemes are provably secure under the intractability of elliptic curve discrete logarithm problem.
A recovery algorithm, named generalized semi-iterative hard thresholding pursuit, was proposed. The algorithm modifies the searching direction of objective function with semi-iterative idea, has a polynomial acceleration convergence, and can be used for the signal without sparse information. It is shown that the proposed algorithm did improve the performance in term of reconstruction probability, peak signal-to-noise ratio, signal-to-noise ratio, and matching rate. The reconstruction quality in ghost imaging with the proposed algorithm is superior to that with the generalized hard thresholding method.
An improved speckle reducing anisotropic diffusion (SRADPRO) algorithm was adopted to reduce the speckle in synthetic aperture radar (SAR) image. An adaptive SAR image segmentation algorithm speckle reducing spiking cortical model (SRSCM) was proposed when SRADPRO and spiking cortical model (SCM) was combined. In SRSCM, the standard deviation was calculated through a uniform sample region in the SAR image, and then the effect degree of speckle can be estimated as a result whether to employ the operator of SRADPRO was determined. At the second stage, the SCM operator was executed. Because of the auto wave characteristic of SCM, the segmented image and edge detection result can be obtained together. The effectiveness of SRSCM was proved by the comparisons with several traditional algorithms.