graph algorithm
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2021 ◽  
Vol 14 (1) ◽  
pp. 171
Author(s):  
Qingyan Wang ◽  
Meng Chen ◽  
Junping Zhang ◽  
Shouqiang Kang ◽  
Yujing Wang

Hyperspectral image (HSI) data classification often faces the problem of the scarcity of labeled samples, which is considered to be one of the major challenges in the field of remote sensing. Although active deep networks have been successfully applied in semi-supervised classification tasks to address this problem, their performance inevitably meets the bottleneck due to the limitation of labeling cost. To address the aforementioned issue, this paper proposes a semi-supervised classification method for hyperspectral images that improves active deep learning. Specifically, the proposed model introduces the random multi-graph algorithm and replaces the expert mark in active learning with the anchor graph algorithm, which can label a considerable amount of unlabeled data precisely and automatically. In this way, a large number of pseudo-labeling samples would be added to the training subsets such that the model could be fine-tuned and the generalization performance could be improved without extra efforts for data manual labeling. Experiments based on three standard HSIs demonstrate that the proposed model can get better performance than other conventional methods, and they also outperform other studied algorithms in the case of a small training set.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259735
Author(s):  
Víctor Muñoz ◽  
N. Elizabeth Garcés

We study the light curves of pulsating variable stars using a complex network approach to build visibility graphs. We consider various types of variables stars (e.g., Cepheids, δ Scuti, RR Lyrae), build two types of graphs (the normal visibility graph (VG) and the horizontal visibility graph (HVG)), and calculate various metrics for the resulting networks. We find that all networks have a power-law degree distribution for the VG and an exponential distribution for the HVG, suggesting that it is a universal feature, regardless of the pulsation features. Metrics such as the average degree, the clustering coefficient and the transitivity coefficient, can distinguish between some star types. We also observe that the results are not strongly affected by the presence of observation gaps in the light curves. These findings suggest that the visibility graph algorithm may be a useful technique to study variability in stars.


Electronics ◽  
2021 ◽  
Vol 10 (21) ◽  
pp. 2659
Author(s):  
Olga A. Safaryan ◽  
Kirill S. Lemeshko ◽  
Alexey N. Beskopylny ◽  
Larissa V. Cherckesova ◽  
Denis A. Korochentsev

Blockchain is one of the leading data transfer technologies that eliminate the need for centralized management through consensus algorithms. This article describes the consensus algorithms, their benefits, and their applications within a micropayment system in the financial sector. Preliminary studies have shown that the performance of distributed databases largely depends on the chosen consensus algorithm. The main task of the study is to create a mathematical model to assess their performance. The most popular crypto projects and the consensus algorithms are analyzed to determine their performance. The obtained model was tested by calculating the parameters of the distributed register based on the directed acyclic graph algorithm and calculating the parameters of other algorithms used. The result is a mathematical model for evaluating the parametric characteristics of the work of consensus algorithms with the choice of the most priority one for implementation in the financial sector. The analysis focuses on the mathematical steps taken by each consensus algorithm. The data obtained using the developed mathematical model demonstrates that PoW, PoS, and DAG algorithms depend on various resources, such as computing power, the number of connected nodes, and the speed of receiving transactions.


Author(s):  
Zhen You ◽  
Jiewen Huang ◽  
Jinyun Xue ◽  
Jiaxiang Chen ◽  
Jiaxin Liu ◽  
...  

Distributed Virtual Reality (DVR) is a combination of network and virtual reality technology, it could facilitate to construct a uniformly shared Distributed Virtual Environment (DVE) by using network to connect geographically distributed multiplayers. This paper concentrates on the theoretical research and practical development about Multiplayer Virtual Intelligent System (MVIS), and the main contribution could be summarized as two points. (1) Based on the DVR technology, this paper presented some theoretical research on MVIS, including the classification of virtual entities, communication pattern of entities, and the behavioral consistency research. Furthermore, a Multiplayer Earliest Deadline First (MEDF) program was proposed in order to guarantee the consistency of entities. (2) A prototype algorithm experiment system, called Multiplayer Graph-algorithm Intelligent System (MGIS), was designed. MGIS not onlyefficiently solves many problems in traditional computer algorithm teaching, such as high-abstraction, difficulty to understand, and lack of interaction mechanism; but also extends the application of DVR to cultural tourism, because MGIS is developed on the 3D scene of Lushan Mountain, which is one of the notable tourist attractions in China, and was included in the UNESCO World Heritage list in 1996. What i’s more, MGIS illustrates the ability of expression, applicability and generality of the theoretical research about MVIS.


2021 ◽  
Author(s):  
Dwi Sunaryono ◽  
Annas Nuril Iman ◽  
Diana Purwitasari ◽  
Agus Budi Raharjo

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhiqiang Qu ◽  
Yujie Zhang ◽  
Fan Li

Joint punishment for dishonesty is an important means of administrative regulation. This research analyzed the dynamic characteristics of time series data from the Baidu search index using the keywords “joint punishment for dishonesty” based on a visibility graph network. Applying a visibility graph algorithm, time series data from the Baidu Index was transformed into complex networks, with parameters calculated to analyze the topological structure. Results showed differences in the use of joint punishment for dishonesty in certain provinces by calculating the parameters of the time series network from January 1, 2020 to May 27, 2021; it was also shown that most of the networks were scale-free. Finally, the results of K-means clustering showed that the 31 provinces (excluding Hong Kong, Macao and Taiwan) can be divided into four types. Meanwhile, by analyzing the national Baidu Index data from 2020 to May 2021, the period of the time series data and the influence range of the central node were found.


2021 ◽  
Vol 11 (18) ◽  
pp. 8761
Author(s):  
Ahmad Naebi ◽  
Zuren Feng ◽  
Farhoud Hosseinpour ◽  
Gahder Abdollahi

One of the main challenges in studying brain signals is the large size of the data due to the use of many electrodes and the time-consuming sampling. Choosing the right dimensional reduction method can lead to a reduction in the data processing time. Evolutionary algorithms are one of the methods used to reduce the dimensions in the field of EEG brain signals, which have shown better performance than other common methods. In this article, (1) a new Bond Graph algorithm (BGA) is introduced that has demonstrated better performance on eight benchmark functions compared to genetic algorithm and particle swarm optimization. Our algorithm has fast convergence and does not get stuck in local optimums. (2) Reductions of features, electrodes, and the frequency range have been evaluated simultaneously for brain signals (left-handed and right-handed). BGA and other algorithms are used to reduce features. (3) Feature extraction and feature selection (with algorithms) for time domain, frequency domain, wavelet coefficients, and autoregression have been studied as well as electrode reduction and frequency interval reduction. (4) First, the features/properties (algorithms) are reduced, the electrodes are reduced, and the frequency range is reduced, which is followed by the construction of new signals based on the proposed formulas. Then, a Common Spatial Pattern is used to remove noise and feature extraction and is classified by a classifier. (5) A separate study with a deep sampling method has been implemented as feature selection in several layers with functions and different window sizes. This part is also associated with reducing the feature and reducing the frequency range. All items expressed in data set IIa from BCI competition IV (the left hand and right hand) have been evaluated between one and three channels, with better results for similar cases (in close proximity). Our method demonstrated an increased accuracy by 5 to 8% and an increased kappa by 5%.


2021 ◽  
Vol vol. 23, no. 3 (Distributed Computing and...) ◽  
Author(s):  
Laurent Feuilloley

A distributed graph algorithm is basically an algorithm where every node of a graph can look at its neighborhood at some distance in the graph and chose its output. As distributed environment are subject to faults, an important issue is to be able to check that the output is correct, or in general that the network is in proper configuration with respect to some predicate. One would like this checking to be very local, to avoid using too much resources. Unfortunately most predicates cannot be checked this way, and that is where certification comes into play. Local certification (also known as proof-labeling schemes, locally checkable proofs or distributed verification) consists in assigning labels to the nodes, that certify that the configuration is correct. There are several point of view on this topic: it can be seen as a part of self-stabilizing algorithms, as labeling problem, or as a non-deterministic distributed decision. This paper is an introduction to the domain of local certification, giving an overview of the history, the techniques and the current research directions.


2021 ◽  
Author(s):  
Michael Burch ◽  
Günter Wallner ◽  
Huub van de Wetering ◽  
Freek Rooks ◽  
Olof Morra

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