Chaos, Solitons and Fractals: X最新文献_第7页

COVID-19: The unreasonable effectiveness of simple models COVID-19:简单模型的不合理有效性

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100034

Timoteo Carletti , Duccio Fanelli , Francesco Piazza

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引用次数: 48

Energy transfer and thermodynamics of quantum gravity computation 量子引力计算的能量传递和热力学

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100050

Laszlo Gyongyosi

引用次数: 1

The scaling of physics-informed machine learning with data and dimensions 基于物理的机器学习的数据和维度缩放

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100046

Scott T. Miller , John F. Lindner , Anshul Choudhary , Sudeshna Sinha , William L. Ditto

引用次数: 11

Generalized trapezoidal ogive curves for fatality rate modeling 用于死亡率建模的广义梯形ogive曲线

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100043

Johan René van Dorp , Ekundayo Shittu , Thomas A. Mazzuchi

{"title":"Generalized trapezoidal ogive curves for fatality rate modeling","authors":"Johan René van Dorp , Ekundayo Shittu , Thomas A. Mazzuchi","doi":"10.1016/j.csfx.2020.100043","DOIUrl":"10.1016/j.csfx.2020.100043","url":null,"abstract":"<div><p>The construction of a continuous family of distributions on a compact set is demonstrated by concatenating, in a continuous manner, three probability density functions with bounded support using a modified mixture technique. The construction technique is similar to that of generalized trapezoidal (GT) distributions, but contrary to GT distributions, the resulting density function is smooth within its bounded domain. The construction of Generalized Trapezoidal Ogive (GTO) distributions was motivated by the COVID-19 epidemic, where smoothness of an infection rate curve may be a desirable property combined with the ability to separately model three stages and their durations as the epidemic progresses, being: (1) an increasing infection rate stage, (2) an infection rate stage of some stability and (3) a decreasing infection rate stage. The resulting model allows for asymmetry of the infection rate curve opposite to, for example, the Gaussian Error Infection (GEI) rate curve utilized early on for COVID-19 epidemic projections by the Institute for Health Metrics and Evaluation (IHME). While other asymmetric distributions too allow for the modeling of asymmetry, the ability to separately model the above three stages of an epidemic’s progression is a distinct feature of the model proposed. The latter avoids unrealistic projections of an epidemic’s right-tail in the absence of right tail data, which is an artifact of any fatality rate model where a left-tail fit determines its right-tail behavior.</p></div>","PeriodicalId":37147,"journal":{"name":"Chaos, Solitons and Fractals: X","volume":"5 ","pages":"Article 100043"},"PeriodicalIF":0.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.csfx.2020.100043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49103484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Exact propagating wave solutions in reaction cross-diffusion system 反应交叉扩散系统的精确传播波解

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100049

Abdullah Aldurayhim , Vadim N. Biktashev

引用次数: 0

Topic reading dynamics of the Chinese Sina-Microblog 中文新浪微博的话题阅读动态

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100031

Fulian Yin , Jiale Wu , Xueying Shao , Jianhong Wu

{"title":"Topic reading dynamics of the Chinese Sina-Microblog","authors":"Fulian Yin , Jiale Wu , Xueying Shao , Jianhong Wu","doi":"10.1016/j.csfx.2020.100031","DOIUrl":"10.1016/j.csfx.2020.100031","url":null,"abstract":"<div><p>A topic in the Sina-Microblog consists of multiple Weibos sharing a specific set of key words. Therefore, a reader of a Weibo may be susceptible to other Weibos of the same topic, and hence may undergo multiple transitions between the susceptible and the exposed states before eventually becoming infectious. This complicates the reading dynamics that traditional epidemic susceptible-exposed-infectious compartmental models cannot capture, and requires a different setting than a single Weibo forwarding dynamics model. Here we formulate a topic reading dynamics model; introduce some summative indices characterizing the reading “outbreak” potential; derive analytic formulae to calculate these indices; and examine the sensitivity of these indices and the ability of prediction on model parameters and on sampling frequencies. We conduct some numerical experiments based on historical data of popular reading topics in the Chinese Sina-Microblog. In our experiments, different sampling frequencies (4 h, 8 h or 12 h) nearcasting the turning points are feasible, in particular, a good nearcasting prediction for the accumulated R-users are 72 h with the sampling frequencies of every 4 h and every 12 h and 78 h with the sampling frequency of every 8 h.</p></div>","PeriodicalId":37147,"journal":{"name":"Chaos, Solitons and Fractals: X","volume":"5 ","pages":"Article 100031"},"PeriodicalIF":0.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.csfx.2020.100031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"95184501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

The interplay between physical activity and aging in locomotor fractal behavior 运动分形行为中体力活动与衰老的相互作用

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100045

Scott W. Ducharme , Richard E.A. van Emmerik

{"title":"The interplay between physical activity and aging in locomotor fractal behavior","authors":"Scott W. Ducharme , Richard E.A. van Emmerik","doi":"10.1016/j.csfx.2020.100045","DOIUrl":"10.1016/j.csfx.2020.100045","url":null,"abstract":"<div><p>The complex organization of gait variability, or fractal dynamics, theoretically represents the adaptive capacity of the locomotor system. Prior studies suggest that fractal dynamics are sensitive to various individual constraints (e.g., age, neurological disease) and task constraints (e.g., walking speed or novel gait tasks). The purpose of this study was to determine if physical activity levels represent an additional individual constraint during walking. Fifteen young and 15 older adults walked on a treadmill at their preferred walking speed and at half of their preferred speed. Detrended fluctuation analysis was used to estimate the statistical persistence of stride time variability. Volume of physical activity was determined using a wearable monitor for 3-7 days. Habitual physical activity levels did not appear to have an effect on the fractal nature of stride-to-stride fluctuations in young adults. However, the least active older adults displayed higher scaling exponents compared to the more active older adults during slow walking. That is, less active older adults responded to the slow walking task by increasing fractal scaling, suggesting this task is more challenging and complex. These findings suggest that lower levels of habitual physical activity may represent an additional individual constraint in older but not young adults. When age and physical activity constraints are combined with a challenging slow walking task, the locomotor system of older adults may be more highly taxed, ultimately manifesting as stronger statistical persistence.</p></div>","PeriodicalId":37147,"journal":{"name":"Chaos, Solitons and Fractals: X","volume":"5 ","pages":"Article 100045"},"PeriodicalIF":0.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.csfx.2020.100045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"104670342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Distinguished correlation properties of Chebyshev dynamical systems and their generalisations 切比雪夫动力系统的显著相关性质及其推广

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100035

Jin Yan, Christian Beck

引用次数: 4

Comment on “Estimation of COVID-19 dynamics “on a back-of-envelope”: Does the simplest SIR model provide quantitative parameters and predictions?” 评论“最简单的SIR模型能提供定量参数和预测吗?”

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100047

S. Rojas

引用次数: 2

Hyers-Ulam stability and existence of solutions for weighted Caputo-Fabrizio fractional differential equations 加权Caputo-Fabrizio分数阶微分方程的Hyers-Ulam稳定性和解的存在性

Chaos, Solitons and Fractals: X Pub Date : 2020-03-01 DOI: 10.1016/j.csfx.2020.100040

Xia Wu, Fulai Chen, Sufang Deng

引用次数: 3