Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2022-05-18 Cooperative journals: 《计算机应用研究》
Abstract： In recent years, the application of drones has become more and more common, and multiple drones can work together to complete tasks, which greatly improves work efficiency. Based on this phenomenon, many scholars devote themselves to the research on the communication mode of UAV swarms, and routing protocols are always the focus of network research. Aiming at the problem that the routing metric selected in the research of routing protocols in the existing literature fails to combine the performance level of the UAV self-organizing network at that time and results in unreasonable routing decisions, this paper proposed a multi-indicator and multi-path optimized link state routing protocol with load awareness and network topology change awareness (Optimized Link State Routing Protocol based on Multi-indicators and Multi-Path, MIMP-OLSR) . Firstly, the proposed protocol considered the mobility characteristics of nodes and the lifetime of the network in the UAV scene, and defined three indicators for routing, namely the node's MAC layer blocking degree, the node's neighbor change rate and the number of MPR_S neighbors of the node; Secondly, combined with HELLO and TC control messages, this paper proposed an indicator notification mechanism to flood the indicator information to the whole nodes of the network; Finally, according to the indicator information, this paper proposed a multi-path routing scheme. The Simulation results show that compared with OLSR, SETT_MPOLSR and UAV-OLSR protocols, the proposed MIMP-OLSR protocol significantly improves success rate, end-to-end delay and throughput performance, which further proves the rationality of the proposed multipath routing scheme.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2022-05-18 Cooperative journals: 《计算机应用研究》
Abstract： Aiming at the problems of long time delay and high computation cost of using complex bilinear mapping in the current LEO satellite network authentication scheme, this paper proposed an efficient certificateless authentication scheme based on the Gayathri’s certificateless authentication scheme. This scheme unifies the user's public key and real identity, so that need not the third party to participate in the authentication process and reduce the authentication delay; uses a small number of point multiplication and point addition operations on the elliptic curve to construct the authentication message, which does not involve the bilinear mapping and reduces the computation cost. Then this paper proves the authentication scheme’s security based on the assumption of elliptic curve discrete mathematics under the random oracle model. Finally, through experimental simulation, comparing with the existing LEO satellite identity authentication schemes, the proposed scheme has lower authentication delay, computational overhead and communication overhead.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2022-04-07 Cooperative journals: 《计算机应用研究》
Abstract： Aiming at the problems of coverage voids of base stations and local traffic overload in urban vehicle networking, this paper proposes a dynamic pre-deployment scheme based on vehicle trajectory prediction information. Firstly, multiple UAVs equipped with edge computing servers remove the central aggregation node under the architecture of distributed federated learning and blockchain and adopt an improved Raft algorithm to train a unified Seq2Seq-GRU trajectory prediction model. In the round of training, according to the amount of contributed data, the scheme elects the nodes to complete the parameter aggregation and model updating tasks. Secondly, based on the prediction results of the model, this paper proposes an improved virtual force guide deployment algorithm, which guides the UAV to dynamically deploy through each virtual force to improve the access rate and communication quality of the vehicle. The simulation results show that the proposed training architecture can accelerate the training of the model, and the deployment algorithm improves the access rate of the vehicle while improving the communication quality between the vehicle and the UAV.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2022-04-07 Cooperative journals: 《计算机应用研究》
Abstract： In order to meet the individual needs of end users and reduce the transmission delay of D2D networks, this paper proposes an Instantly Solvable Network Coding (IDNC) cooperative retransmission scheme based on terminal differentiation. First of all, this scheme proposes a new IDNC algorithm framework for the decoding conflict and transmission conflict in PC-D2D networks, and searches for a maximal independent set (MIS) on the basis of this framework. User requirements and link packet loss rate are designed for weights, and the weights are selected to generate coded packets by combining the concurrent cooperative retransmission terminal with the smallest retransmission delay increment and data packets. At the same time, considering the future decoding opportunities provided by unnecessary data packets, optimize the data packets that the terminal does not need to further reduce the transmission delay. The simulation results show that the proposed scheme can effectively reduce the decoding delay and completion time while meeting the personalized needs of the terminal.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2019-05-10 Cooperative journals: 《计算机应用研究》
Abstract： In order to solve the problem of the fractional Fourier transform（FRFT）in estimating the multipath delay for Chirp signal, this study proposed an improved FRFT multipath delay estimation algorithm based on the energy of each multipath component. The algorithm sequentially returns the estimated values of multipath components by iteration according to the energy magnitude of multipath components. In each iteration, there are a sub-iteration to accurately estimate the parameter and location of the current component, and then generates a time domain copy of the sounding signal, which is subtracted from the residual signal to reach separation of the multipath signal. This paper made some experiments which use channel model based on the characteristics of power delay distribution. and the results show that the improved algorithm can estimate the multipath delay more accurately than the other three delay estimation approaches.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2019-01-28 Cooperative journals: 《计算机应用研究》
Abstract： There is a certain internal relationship between user links and location links in location-based social network(LBSN) , and different users also have different behaviors in the network. Therefore, view of the above problem, a Cooperation based personalized link prediction algorithm(CPP) is proposed in LBSN. For the user's personalized features, the kernel density estimation method is used to model the user's time and spatial dimensions. The interest groups were used to divide the users into overlapping communities, and the personalized user link prediction was performed through the community, friends and sign-in relationships. Based on the prediction of the personalized user link, a personalized link relationship between users and locations was predicted via the algorithm of the random walk with community restarting. The CPP algorithm improves the performance by the iteration of the user link prediction and the location link prediction. The experimental results show that the CPP algorithm has better prediction performance than that of the existing algorithm.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2019-01-03 Cooperative journals: 《计算机应用研究》
Abstract： Pilot contamination is the bottleneck of the multi-cell Massive MIMO systems, and mitigating pilot contamination is critical to the Massive MIMO. This paper proposes a pilot allocation scheme that combines user location and spatial distance. All users are clustered according to whether the angle of arrival overlaps, and classifies the user sets whose arrival angles do not overlap each other into n sets. then the remaining users who do not satisfy the condition are classified into the n+1 classes. Assigning n sets of pilot sequences to the first n types of user sets is multiplexed within the set, and for users in the n+1 class set, the paper defines an interference function to construct a weighted graph. At the same time, it derives the user's expression of the uplink spectrum efficiency. The simulation results show that the scheme can significantly improve the spectrum efficiency.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2019-01-03 Cooperative journals: 《计算机应用研究》
Abstract： Concern the problem that multi-channel Motor Imagery (MI) of Brain-Computer Interface (BCI) based on 3D visual guidance with more redundancy information and poor classification accuracy, this paper proposed a pattern classification method based on wavelet packet decomposition(WPD)-common spatial pattern(CSP)-adaptive differential evolution(ADE) for feature extraction of electroencephalogram（EEG）.Firstly, this algorithm used WPD to divide the multi-channel motion imagery EEG signals into fine sub-bands. Secondly, it used CSP to obtain the eigenvectors corresponding to each subspace of WPD transformation. Finally, it selected the feature vectors through the ADE algorithm to obtain the best feature subsets for classification. Using WPD-CSP-ADE mode for feature extraction and selection, it had better performance in classification accuracy and number of features than the classic WPD-CSP method. At the same time, the classification performance of the proposed algorithm was significantly better than the genetic algorithm and particle swarm optimization algorithm. The experiments show that the WPD-CSP-ADE method can effectively improve the classification accuracy and reduce the number of features used for classification.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-11-29 Cooperative journals: 《计算机应用研究》
Abstract： Aiming at the security problems existing in the process of the data aggregation and transmission in crowd sensing networks, such as privacy leakage, incomplete information, data tampering. this paper proposed a data aggregation privacy protection algorithm based on distributed compressive sensing and hash function. Firstly, it used distributed compressive sensing method to sparsely observe the sensed data and remove the redundant data. Then, it utilized one-way hash function to obtain hash value of the observation data and filled the hash value with the unconstrained camouflage data into the observation data of sensory data to reach the aim of concealing the true sensor data. Finally, after extracting the camouflage data at the sink node, it obtained the hash value of the observation data again to verify the integrity of data. Simulation results show that the algorithm takes into account the privacy preserving and integrity protecting of data, and also can reduce the communication overhead greatly, which means the strong applicability and scalability in practical applications.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-11-29 Cooperative journals: 《计算机应用研究》
Abstract： In order to improve the efficiency of task offloading in Ad hoc cloud, aiming at the effect of node random movement and resource heterogeneity on task offloading, this paper proposes the multi criteria task offloading algorithm based on mobility prediction, which is used to predict node escaping time based on time series analysis and as a measure of mobility. By using the analytic hierarchy process to get the weights of CPU speed, number of cores, workload and mobility, the task is offloaded according to task size and the combined weights which has been calculated, the simulation results show that the algorithm can reduce the task execution time and energy consumption effectively compared with the random task assignment algorithm and Min-Min scheduling algorithm.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-24 Cooperative journals: 《计算机应用研究》
Abstract： For the problem that the ICI self-cancellation algorithm leads to the underutilization of the UFMC system frequency band, this paper proposed an improved scheme that combines partial self-cancellation and raised cosine windows. This scheme specifically inserted the self-eliminating sub-carriers into the UFMC system's transmitting terminal band boundary, and performed windowing in the time domain at the receiving end of the UFMC system to achieve the purpose of suppressing UFMC system interference and improving system band utilization. This爌aper燾onducted爏imulation爀xperiments爋f the algorithm on燤ATLAB爌latform. There were four self-cancelled sub-carriers on both sides of the sub-band, the system carrier-to-interference ratio increased compared with the self-cancellation algorithm, and the spectrum utilization of the system also increased by 10%. The simulation results showed that the proposed algorithm could effectively suppress ICI, improve the system's anti-jamming performance, and improve the system bandwidth utilization.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-24 Cooperative journals: 《计算机应用研究》
Abstract： Detection of communitiy structure is significant in understanding the structures and functions of the complex network. In view of the problem of the slowness of the community diffusion and not suitable for large-scale network, The paper proposed a local community detection algorithm based on breadth first traversal. The algorithm finds out the node with lowest degree in the network, and uses this node as a starting point to divide the nodes into community nodes and boundary nodes to form the initial community detection by influence function. Then use fitness function to get the final cover. The experimental results show that the algorithm tested in a real network can effectively dig out community structure in the network and have faster speed.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-20 Cooperative journals: 《计算机应用研究》
Abstract： Targeted at the image lower quality due to insufficient shine, a method for image enhancement based on the separation of structure layer and texture layer is proposed. Firstly, break down the image to structure layer and texture layer. Then use the cumulative distribution function to construct the parameter self-adaptive Gamma correction algorithm for the structure layer, and use the same algorithm to enhance the contrast ratio and light intensity of the image structure layer and adopt the method of high frequency component to enhance the texture details in the texture layer. Finally, combine the enhanced structure layer and texture layer and get the enhanced image. The simulation contrast experiment proves that the method may avoid the loss of texture details in the process of image enhancement and improve the light intensity as well as the contrast ratio to large extent, making the enhance image much better in visual effect. It is certainly valuable in the application.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-18 Cooperative journals: 《计算机应用研究》
Abstract： The existing privacy protection strategies in crowd sensing networks used the same privacy policies for all locations which overprotected led to the problems that some locations, others were not adequately protected and the sensing data was less accurate. In order to solve this problem, this paper proposed a location privacy protection algorithm to meet the users’ personalized privacy and security requirements. First, it mined users’ access duration, frequency and regularity at different locations according to the user's historical movement trajectory, which used to predict the social attributes of the locations to the users. Then, it combined the location’s social attributes and natural attributes to predict user-location sensitivity levels. Finally, considering the different privacy security requirements of users in different locations, it set a dynamic privacy decision scheme. Users with less sensitivity at each location were selected to participate in sensing tasks to ensure that users, in the safe privacy context, could contribute the accurate data with a higher level of spatiotemporal correlation. The simulation results show that the algorithm can improve the privacy protection level and the accuracy of the sensing data.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-04-19 Cooperative journals: 《计算机应用研究》
Abstract： In order to decrease the energy consumption of wireless communication system and ensure the user experience quality, this paper proposed a QoE-based energy efficiency resource allocation algorithm for LTE-A system. First, a mathematical model for jointly optimizing QoE and energy efficiency was proposed, especially considering the minimum QoE requirement of users. Secondly, an iterative algorithm was proposed to allocate user resource blocks (RBs) according to the constraints. Then, the optimal objective function was optimized by using the properties of fractional programming and using the convex optimization method to obtain the optimal transmit power. Simulation results show that compared with the existing energy efficiency resource allocation algorithm, the proposed algorithm can effectively guaranteed user's QoE while improving system performance.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-04-12 Cooperative journals: 《计算机应用研究》
Abstract： ABSTRACT: In LTE-A, it may result in congestion when massive devices initiate almost simultaneously a random access request to the base station, and then the access delay will be increased and the quality of service will be not satisfied. By analyzing the random access model of slotted access, this paper proposed an access congestion control mechanism based on slot access cycle decision adaptively with the estimation of access load. Compared with the slotted-access-based channel access control protocol (SCACP) , this paper optimized the choice of slot access cycle to counterbalance the timeslot access load for the sake of access success probability and access delay. Finally, the simulation results demonstrated the effectiveness of the access congestion control mechanism.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-04-12 Cooperative journals: 《计算机应用研究》
Abstract： In view of the current D2D multicast content delivery mechanism has a large amount of transmission redundancy, lead to low energy efficiency and low spectrum efficiency. This paper proposed a novel demand-aware D2D video distribution mechanism. By predicting users’ video service requests, the video is pushed to potential service users while distributing video for service request users. Firstly, the willingness of potential service users to accept video push is estimated based on the users’ interests, the popularity of the video and the residual-energy of the users’ devices. Secondly, the utility measure of video distribution service was proposed to measure the value of video distribution service, and the issue on energy efficiency of the optimal cluster heads was modeled. Finally, this paper proposed a D2D video distribution mechanism that optimizes the energy efficiency of cluster heads. Simulation results show that the proposed mechanism is superior to the traditional ones with regard to the energy efficiency of the cluster head and system throughput.
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