Journal of Physics Complexity最新文献_第10页

Outlier mining in high-dimensional data using the Jensen–Shannon divergence and graph structure analysis 基于Jensen–Shannon散度和图结构分析的高维数据异常点挖掘

IF 2.7

Journal of Physics Complexity Pub Date : 2022-12-06 DOI: 10.1088/2632-072X/aca94a

Alex S O Toledo, Riccardo Silini, L. Carpi, C. Masoller

{"title":"Outlier mining in high-dimensional data using the Jensen–Shannon divergence and graph structure analysis","authors":"Alex S O Toledo, Riccardo Silini, L. Carpi, C. Masoller","doi":"10.1088/2632-072X/aca94a","DOIUrl":"https://doi.org/10.1088/2632-072X/aca94a","url":null,"abstract":"Reliable anomaly/outlier detection algorithms have practical applications in many fields. For instance, anomaly detection allows to filter and clean the data used to train machine learning algorithms, improving their performance. However, outlier mining is challenging when the data is high-dimensional, and different approaches have been proposed for different types of data (temporal, spatial, network, etc). Here we propose a methodology to mine outliers in generic datasets in which it is possible to define a meaningful distance between elements of the dataset. The methodology is based on defining a fully connected, undirected graph, where the nodes are the elements of the dataset and the links have weights that are the distances between the nodes. Outlier scores are defined by analyzing the structure of the graph, in particular, by using the Jensen–Shannon (JS) divergence to compare the distributions of weights of different nodes. We demonstrate the method using a publicly available database of credit-card transactions, where some of the transactions are labeled as frauds. We compare with the performance obtained when using Euclidean distances and graph percolation, and show that the JS divergence leads to performance improvement, but increases the computational cost.","PeriodicalId":53211,"journal":{"name":"Journal of Physics Complexity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47136226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Thoughts on complex systems: an interview with Giorgio Parisi 对复杂系统的思考:对乔治·帕里西的采访

IF 2.7

Journal of Physics Complexity Pub Date : 2022-12-01 DOI: 10.1088/2632-072X/ac9171

G. Parisi

引用次数: 1

Autorrelation and cross-relation of graphs and networks 图和网络的自关系和相互关系

IF 2.7

Journal of Physics Complexity Pub Date : 2022-12-01 DOI: 10.1088/2632-072X/aca57c

L. da Fontoura Costa

{"title":"Autorrelation and cross-relation of graphs and networks","authors":"L. da Fontoura Costa","doi":"10.1088/2632-072X/aca57c","DOIUrl":"https://doi.org/10.1088/2632-072X/aca57c","url":null,"abstract":"The concepts of auto- and cross-correlation play a key role in several areas, including signal processing and analysis, pattern recognition, multivariate statistics, as well as physics in general, as these operations underlie several real-world structures and dynamics. In the present work, the concept of multiset similarity, more specifically the coincidence similarity index, is used as the basis for defining operations between a same network, or two distinct networks, which will be respectively called autorrelation and cross-relation. In analogous manner to the autocorrelation and cross-correlation counterparts, which are defined in terms of inner products between signals, the two operations suggested here allow the comparison of the similarity of nodes and graphs respectively to successive displacements along the neighborhoods of each of the constituent nodes, which therefore plays a role that is analogue to the lag in the class correlation. In addition to presenting these approaches, this work also illustrates their potential respectively to applications for the characterization of several model-theoretic and real world networks, providing a comprehensive description of the specific properties of each analyzed structure. The possibility of analyzing the obtained individual autorrelation signatures in terms of their respective coincidence similarity networks is also addressed and illustrated.","PeriodicalId":53211,"journal":{"name":"Journal of Physics Complexity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46042397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Minor extensions of the logistic equation for growth curves of word counts on online media: parametric observation of diversity of growth in society 网络媒体字数增长曲线逻辑方程的小扩展：社会增长多样性的参数观察

IF 2.7

Journal of Physics Complexity Pub Date : 2022-11-30 DOI: 10.1088/2632-072X/acda72

Hayafumi Watanabe

{"title":"Minor extensions of the logistic equation for growth curves of word counts on online media: parametric observation of diversity of growth in society","authors":"Hayafumi Watanabe","doi":"10.1088/2632-072X/acda72","DOIUrl":"https://doi.org/10.1088/2632-072X/acda72","url":null,"abstract":"To understand the growth phenomena in collective human systems, we analyzed monthly word count time series of new vocabularies extracted from approximately 1 billion Japanese blog articles from 2007 to 2019. In particular, we first introduced the extended logistic equation by adding one parameter to the original equation and showed that the model can consistently reproduce various patterns of actual growth curves, such as the logistic function, linear growth, and finite-time divergence. Second, by analyzing the model parameters, we found that the typical growth pattern is not only a logistic function, which often appears in various complex systems, but also a non-trivial growth curve that starts with an exponential function and asymptotically approaches a power function without a steady state. We also observed a connection between the functional form of growth and the peak-out behavior. Finally, we showed that the proposed model and statistical properties are also valid for Google Trends data (English, French, Spanish, and Japanese), which is a time series of the nationwide popularity of search queries.","PeriodicalId":53211,"journal":{"name":"Journal of Physics Complexity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45488355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The stochastic nature of power-grid frequency in South Africa 南非电网频率的随机性

IF 2.7

Journal of Physics Complexity Pub Date : 2022-11-10 DOI: 10.1088/2632-072X/acb629

Leonardo Rydin Gorjão, J. Maritz

引用次数: 2

Klaus Hasselmann and Economics 克劳斯·哈塞尔曼与经济学

IF 2.7

Journal of Physics Complexity Pub Date : 2022-11-03 DOI: 10.1088/2632-072X/ac956e

C. Jaeger

{"title":"Klaus Hasselmann and Economics","authors":"C. Jaeger","doi":"10.1088/2632-072X/ac956e","DOIUrl":"https://doi.org/10.1088/2632-072X/ac956e","url":null,"abstract":"Klaus Hasselmann has earned the 2021 Nobel Prize in physics for his breakthroughs in analysing the climate system as a complex physical system. Since decades, as a leading climate scientist he is aware of the need for creative cooperation between climate scientists and researchers from other fields, especially economics. To facilitate such cooperation, he has designed a productive research program for economic analysis in view of climate change. Without blurring the differences between economics and physics, the Hasselmann program stresses the complexities of today’s economy. This includes the importance of heterogeneous actors and different time scales, of making major uncertainties explicit and bringing researchers and practitioners in close interaction. The program has triggered decades of collaborative research, especially in the network of the Global Climate Forum, that he has founded for this purpose. Research inspired by Hasselmann’s innovative ideas has led to a farewell to outdated economic approaches: single-equilibrium models, a single constant discount rate, framing the climate challenge as a kind of prisoner’s dilemma and framing it as a problem of scarcity requiring sacrifices from the majority of today’s population. Instead of presenting the climate problem as the ultimate apocalyptic narrative, he sees it as a challenge to be mastered. To meet this challenge requires careful research in order to identify underutilisation of human, technical and social capacities that offer the keys to a climate friendly world economy. Climate neutrality may then be achieved by activating these capacities through investment-oriented climate strategies, designed and implemented by different actors both in industrialised and developing countries. The difficulties to bring global greenhouse gas emissions down to net zero are enormous; the Hasselmann program holds promise of significant advances in this endeavour.","PeriodicalId":53211,"journal":{"name":"Journal of Physics Complexity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47423294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

General Vapnik–Chervonenkis dimension bounds for quantum circuit learning 量子电路学习的一般Vapnik-Chervonenkis维限

IF 2.7

Journal of Physics Complexity Pub Date : 2022-11-02 DOI: 10.1088/2632-072X/ac9f9b

Chih-Chieh Chen, Masaru Sogabe, Kodai Shiba, K. Sakamoto, T. Sogabe

引用次数: 1

Permutation entropy of indexed ensembles: quantifying thermalization dynamics 索引系综的排列熵：量化热化动力学

IF 2.7

Journal of Physics Complexity Pub Date : 2022-10-27 DOI: 10.1088/2632-072X/acd742

A. Aragoneses, A. Kapulkin, Arjendu K. Pattanayak

{"title":"Permutation entropy of indexed ensembles: quantifying thermalization dynamics","authors":"A. Aragoneses, A. Kapulkin, Arjendu K. Pattanayak","doi":"10.1088/2632-072X/acd742","DOIUrl":"https://doi.org/10.1088/2632-072X/acd742","url":null,"abstract":"We introduce ‘PI-Entropy’ Π(ρ˜) (the Permutation entropy of an Indexed ensemble) to quantify mixing due to complex dynamics for an ensemble ρ of different initial states evolving under identical dynamics. We find that Π(ρ˜) acts as an excellent proxy for the thermodynamic entropy S(ρ) but is much more computationally efficient. We study 1-D and 2D iterative maps and find that Π(ρ˜) dynamics distinguish a variety of system time scales and track global loss of information as the ensemble relaxes to equilibrium. There is a universal S-shaped relaxation to equilibrium for generally chaotic systems, and this relaxation is characterized by a shuffling timescale that correlates with the system’s Lyapunov exponent. For the Chirikov Standard Map, a system with a mixed phase space where the chaos grows with nonlinear kick strength K, we find that for high K, Π(ρ˜) behaves like the uniformly hyperbolic 2D Cat Map. For low K we see periodic behavior with a relaxation envelope resembling those of the chaotic regime, but with frequencies that depend on the size and location of the initial ensemble in the mixed phase space as well as K. We discuss how Π(ρ˜) adapts to experimental work and its general utility in quantifying how complex systems change from a low entropy to a high entropy state.","PeriodicalId":53211,"journal":{"name":"Journal of Physics Complexity","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45174614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Synchronization of online social rhythms via avatar communications 通过化身通信同步在线社交节奏

IF 2.7

Journal of Physics Complexity Pub Date : 2022-10-26 DOI: 10.1088/2632-072X/acbd7d

Masanori Takano

引用次数: 0

Coexistence of coordination and anticoordination in nonlinear public goods game 非线性公共产品博弈中的协调与反协调共存

IF 2.7

Journal of Physics Complexity Pub Date : 2022-10-19 DOI: 10.1088/2632-072X/ac9bc0

Arunava Patra, V. Dubey, S. Chakraborty

引用次数: 0