Currently, many efforts have been done towards secure data privacy protection and reliable information trace, however the conventional solutions are still vulnerable to information loss, privacy leakage and other attacks till the blockchain technology emerged. Blockchain can record historical data by establishing a collectively maintained and tamper-resistant public ledger to ensure the security and reliability of the data stored in a distributed network. It realizes a decentralized network architecture, which can bring new solutions to many fields such as information tracing and privacy protection. In recent years, blockchain technology has gradually attracted the close attention of all industries, and this paper summarizes the existing blockchain-based systems and applications. We mainly review the applications of blockchain traceability technology in various fields, the blockchain decentralized applications, and other blockchain applications in data security protection, respectively. This work may bring new opportunities and challenges for the development of various industries in the future.

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Blockchain-based Systems and Applications: A Survey

In scenes high in visual complexity, the identification of a moving object can be affected by changes in scale and occlusion factors during the tracking process, resulting in reduced tracking accuracy. Accordingly, to address the problem of low accuracy, a multiscale fast correlation filtering tracking algorithm based on a feature fusion model is proposed in the present work with the aim of reducing the poor tracking effects caused by occlusion discrimination and scale changes in complex scenes. The object's grayscale (GRAY) feature, histogram of oriented gradient (HOG) feature, and color name (CN) feature are reduced to dimensions and fused to form a feature matrix. Moreover, a hierarchical principal component analysis (HPCA) algorithm is used to extract visually salient features and reconstruct the feature matrix under real‐time conditions, the correlation filtering position is trained, the number of dimensions is effectively reduced, and the feature fusion matrix is used to train the multiscale fast correlation filtering, with the result that the object's position and scale can be accurately predicted. The proposed algorithm is then compared with five popular correlation filtering tracking algorithms. Experimental results demonstrate that its average tracking speed reaches a reasonable frames/second velocity; moreover, it can also achieve promising object tracking results on the OTB benchmark data sets. The tracking accuracy is superior to that of the other five correlation filtering tracking algorithms when applied to scenes featuring object occlusion and changes in scale. The proposed algorithm also exhibits better robustness and improved performance under real‐time conditions in sophisticated scenarios, including scale variation, deformation, fast motion, occlusion, and so on.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/cpe.6589

Multiscale fast correlation filtering tracking algorithm based on a feature fusion model

Much progress can be expected in the domain of unmanned aerial vehicle (UAV) communication by the next decade. The cooperation between multiple UAVs in the air exchanging data among themselves can naturally form a flying ad hoc network (FANET). Such networks can be the key support to accomplish several kinds of missions while providing the required assistance to terrestrial networks. However, they are confronted with many challenges and difficulties, which are due to the high mobility of UAVs, the frequent packet losses, and the weak links between UAVs, all affecting the reliability of the data delivery. Furthermore, the unbalanced energy consumption may result in earlier UAV failure and consequently accelerate the decrease of the network lifetime, thus disrupting the overall network. This paper supports the use of the movement information and the residual energy level of each UAV to guarantee a high level of communication stability while predicting a sudden link breakage prior to its occurrence. A robust route discovery process is used to explore routing paths where the balanced energy consumption, the link breakage prediction, and the connectivity degree of the discovered paths are all considered. The performance of the scheme is evaluated through a series of simulations. The outcomes demonstrate the benefits of the proposed scheme in terms of increasing the lifetime of the network, minimizing the number of path failures, and decreasing the packet losses.

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ECaD: Energy‐efficient routing in flying ad hoc networks

Parameterized computation theory has developed rapidly over the last two decades. In theoretical computer science, it has attracted considerable attention for its theoretical value and significant guidance in many practical applications. We give an overview on parameterized algorithms for some fundamental NP-hard problems, including MaxSAT, Maximum Internal Spanning Trees, Maximum Internal Out-Branching, Planar (Connected) Dominating Set, Feedback Vertex Set, Hyperplane Cover, Vertex Cover, Packing and Matching problems. All of these problems have been widely applied in various areas, such as Internet of Things, Wireless Sensor Networks, Artificial Intelligence, Bioinformatics, Big Data, and so on. In this paper, we are focused on the algorithms’ main idea and algorithmic techniques, and omit the details of them.

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Parameterized algorithms of fundamental NP-hard problems: a survey

MF-Adaboost: LDoS attack detection based on multi-features and improved Adaboost

A node can provide a file to other nodes after downloading the file or data from the Internet. When more than one node have obtained the same file, this is considered a multisource transmission, in which all these nodes can act as candidate providers (sources) and transmit the file to a new request node (destination) together. In cases where there is negligible or no interference, multisource transmission can improve the download throughput because of parallel transmissions through multiple paths. However, this improvement is not guaranteed due to wireless interference among different paths. Wireless interference can be alleviated by the multiradio and multichannel technique. Because the source and multipath routing selections interact with channel assignment, the multisource transmission problem with multiradio and multichannel presents a significant challenge. In this paper, we propose a distributed joint source, routing, and channel selection scheme. The source selection issue can be concurrently solved via multipath finding. There are three sub-algorithms in our scheme, namely, interference-aware routing algorithm, channel assignment algorithm, and local routing adjustment algorithm. The interference-aware routing algorithm is used to find paths sequentially and is jointly executed with the channel assignment algorithm. After finding a new path, the local routing adjustment algorithm may be executed to locally adjust the selected paths so as to further reduce wireless interference. Extensive simulations have been conducted to demonstrate that our algorithms can effectively improve the network aggregate throughput, as well as reduce delay and packet loss probability.

Interference-Aware Multisource Transmission in Multiradio and Multichannel Wireless Network

In a multi-hop wireless network, a node can act as a candidate file provider to other nodes, if it has downloaded the file from the Internet. When another node requires the same file, all nodes which have already obtained the file can act as candidate file providers (sources) and transmit file together to the request node (destination). We form this as the multi-source transmission. As the multi-source transmissions can exploit multiple paths to transmit data, it is an efficient way to largely increase the download throughput. Although it is promising, suffering from wireless interference, all candidate file providers transmitting together in a multi-source transmission may not provide better performance or even worse performance than only a subset of candidate file providers involved. Moreover, to maximize the performance gain, multi-radio and multichannel technique is exploited to alleviate interference, where the source, multi-path routing, and channel are closely related and should be joint solved. The multi-source transmission problem becomes very challenging. This paper is the first study to investigate the multi-source transmission problem in multi-hop wireless network and proposes an interference-aware joint source, routing, and channel selection scheme to solve the problem. Firstly, we propose a novel interference-aware metric (Metric of Path Capacity, MIPC) to capture interference. Based on the metric, we propose three sub-algorithms: interferenceaware routing algorithm, channel selection algorithm, and local routing adjustment algorithm to solve the multi-source transmissions problem. We have done extensive simulations. The simulation results make clear that the proposed scheme can effectively maximize the network throughput.

Chuan Xu

Papers

Interference-Aware Multisource Transmission in Multiradio and Multichannel Wireless Network

Interference-Aware Multi-source Transmission