Hybrid GA-PSO method with local search and image clustering for automatic IFS image reconstruction of fractal colored images

Over the past few decades, the application of iterated function systems (IFS) in reconstructing fractal images has been a challenging research area. Numerous methods have been proposed to address this issue. However, they generally focus on binary or grayscale images, neglecting the color component of the process. Consequently, they are unsuitable for reconstructing colored images. In a previous paper presented at the ISCMI 2021 conference, the authors introduced a novel approach that utilizes the cuckoo search algorithm and k-means clustering for IFS fractal reconstruction of colored images. Building upon that work, this paper introduces an enhanced and extended method by combining genetic algorithms (GAs) and particle swarm optimization (PSO) with local search and image clustering. In this approach, GA and PSO are mutually coupled to automatically determine the color of the contractive functions and the IFS parameters, respectively. The output of each method serves as the input for the other in an iterative manner. Main contributions of this method are: (1) it computes automatically the optimal number and IFS code of the contractive functions; (2) the color of the contractive functions is determined automatically through an optimization process using GA; (3) a local refinement step is performed to further enhance the final solution. Overall, this new method yields highly accurate results in reconstructing the geometry and color of input fractal images, without requiring any additional information about the target beyond the bitmap image

On Selection of a Benchmark by Determining the Algorithms' Qualities

ABSTRACT: The authors got the motivation for writing the article based on an issue, with which developers of the newly developed nature-inspired algorithms are usually confronted today: How to select the test benchmark such that it highlights the quality of the developed algorithm most fairly? In line with this, the CEC Competitions on Real-Parameter Single-Objective Optimization benchmarks that were issued several times in the last decade, serve as a testbed for evaluating the collection of nature-inspired algorithms selected in our study. Indeed, this article addresses two research questions: (1) How the selected benchmark affects the ranking of the particular algorithm, and (2) If it is possible to find the best algorithm capable of outperforming all the others on all the selected benchmarks. Ten outstanding algorithms (also winners of particular competitions) from different periods in the last decade were collected and applied to benchmarks issued during the same time period. A comparative analysis showed that there is a strong correlation between the rankings of the algorithms and the benchmarks used, although some deviations arose in ranking the best algorithms. The possible reasons for these deviations were exposed and commented on.This work was supported in part by the Slovenian Research Agency (Projects J2-1731 and L7-9421) under Grant P2-0041, in part by the Project PDE-GIR of the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie under Grant 778035, and in part by the Spanish Ministry of Science, Innovation and Universities (Computer Science National Program) of the Agencia Estatal de Investigacion and European Funds EFRD (AEI/FEDER, UE) under Grant TIN2017–89275-R

New Perspectives in the Development of the Artificial Sport Trainer

ABSTRACT: The rapid development of computer science and telecommunications has brought new ways and practices to sport training. The artificial sport trainer, founded on computational intelligence algorithms, has gained momentum in the last years. However, artificial sport trainer usually suffers from a lack of automatisation in realization and control phases of the training. In this study, the Digital Twin is proposed as a framework for helping athletes, during realization of training sessions, to make the proper decisions in situations they encounter. The digital twin for artificial sport trainer is based on the cognitive model of humans. This concept has been applied to cycling, where a version of the system on a Raspberry Pi already exists. The results of porting the digital twin on the mentioned platform shows promising potential for its extension to other sport disciplines.Akemi Galvez and Andres Iglesias have received funding from the project PDE-GIR of the European Union’s Horizon 2020 research and innovation programme under the Marie SklodowskaCurie grant agreement no. 778035, and from the project TIN2017-89275-R funded by MCIN/AEI/10.13039/501100011033/FEDER “Una manera de hacer Europa”

Multiwavelength Studies of Young OB Associations

We discuss how contemporary multiwavelength observations of young OB-dominated clusters address long-standing astrophysical questions: Do clusters form rapidly or slowly with an age spread? When do clusters expand and disperse to constitute the field star population? Do rich clusters form by amalgamation of smaller subclusters? What is the pattern and duration of cluster formation in massive star forming regions (MSFRs)? Past observational difficulties in obtaining good stellar censuses of MSFRs have been alleviated in recent studies that combine X-ray and infrared surveys to obtain rich, though still incomplete, censuses of young stars in MSFRs. We describe here one of these efforts, the MYStIX project, that produced a catalog of 31,784 probable members of 20 MSFRs. We find that age spread within clusters are real in the sense that the stars in the core formed after the cluster halo. Cluster expansion is seen in the ensemble of (sub)clusters, and older dispersing populations are found across MSFRs. Direct evidence for subcluster merging is still unconvincing. Long-lived, asynchronous star formation is pervasive across MSFRs.Comment: 22 pages, 9 figures. To appear in "The Origin of Stellar Clusters", edited by Steven Stahler, Springer, 2017, in pres

3D meso-scale modelling of concrete material in spall tests

Tensile strength is one of the key factors of concrete material that need be accurately defined in analysis of concrete structures subjected to high-speed impact loads. Dynamic tensile strength of concrete material is usually obtained by conducting laboratory tests such as direct tensile test, Brazilian splitting test and spall test. Concrete is a heterogeneous material with different components, but is conventionally assumed to be homogeneous, i.e., cement mortar only, in most previous experimental or numerical studies. The aggregates in concrete material are usually neglected owing to testing limitation and numerical simplification. It has been well acknowledged that neglecting coarse aggregates might not necessarily give accurate concrete dynamic material properties. In the present study, a 3D meso-scale model of concrete specimen with consideration of cement mortar and aggregates is developed to simulate spall tests and investigate the behaviour of concrete material under high strain rate. The commercial software LS-DYNA is used to perform the numerical simulations of spall tests. The mesh size sensitivity is examined by conducting mesh convergence tests. The reliability of the numerical model in simulating the spall tests is verified by comparing the numerical results with the experimental data from the literature. The influence of coarse aggregates on the experimental test results is studied. The wave attenuation in concrete specimen is analysed, and empirical equations are proposed for quick assessment of the test data to determine the true dynamic tensile strength of concrete material. The contributions of aggregates to dynamic strength in spall tests are quantified for modifying the test results based on mortar material in the literature

Clinical implications of different types of dementia in patients with atrial fibrillation: Insights from a global federated health network analysis.

BackgroundAtrial fibrillation (AF) associates with higher Alzheimer's disease (AD) and vascular dementia risks but the clinical implications have been scarcely investigated. We examined the association between AD or vascular dementia and adverse outcomes in AF patients.MethodsCohort study between January 2000 and 2017. AF patients were divided into two groups according to vascular dementia or AD, and balanced using propensity score matching (PSM). During 4-years of follow-up, incident intracranial hemorrhages (ICH), the composite of ischemic stroke/transient ischemic attack (TIA), hospitalizations, and all-cause deaths, were recorded.ResultsTwo thousand three hundred seventy-seven AF patients with dementia (1225 with vascular dementia, and 1152 with AD) were identified. Following a PSM, 615 patients were included in each cohort (i.e., 1:1) and all variables were well-matched. After PSM, 22 (3.6%) patients with vascular dementia and 55 (8.1%) patients with AD had incident ICH during follow-up (hazard ratio [HR]: 2.22, 95% confidence interval [CI]: 1.33-3.70, log-rank p = 0.002). Overall, 237 (38.5%) patients with vascular dementia and 193 (31.4%) patients with AD, developed an ischemic stroke/TIA. The risk of ischemic stroke/TIA was 1.32-fold higher in vascular dementia (HR: 1.32, 95% CI: 1.09-1.59, log-rank p = 0.003). The risk of rehospitalization (HR: 1.14, 95% CI: 1.01-1.31), and mortality (HR: 1.25, 95% CI: 1.01-1.58) were also higher among AF patients with vascular dementia compared to AD.ConclusionsThe two forms of dementia in AF patients are associated with different prognosis, with AD being associated with a higher risk of ICH, and vascular dementia with a higher risk of stroke/TIA, hospitalization, and mortality

Sexual behavior and drug consumption among young adults in a shantytown in Lima, Peru

<p>Abstract</p> <p>Background</p> <p>Risky sexual behaviors of young adults have received increasing attention during the last decades. However, few studies have focused on the sexual behavior of young adults in shantytowns of Latin America. Specifically, studies on the association between sexual behaviors and other risk factors for sexually transmitted infections (STI) and HIV/AIDS transmission, such as the consumption of illicit drugs or alcohol are scarce in this specific context.</p> <p>Methods</p> <p>The study participants were 393 men and 400 women between 18 and 30 years of age, from a shantytown in Lima, Peru. Data were obtained via survey: one section applied by a trained research assistant, and a self-reporting section. Logistic regression was used to estimate associations between use of any illicit drug, high-risk sexual behaviors and reported STI symptoms, adjusting for alcohol consumption level and various socio-demographic characteristics.</p> <p>Results</p> <p>Among men, age of sexual debut was lower, number of lifetime sexual partners was higher, and there were higher risk types of sexual partners, compared to women. Though consistent condom use with casual partners was low in both groups, reported condom use at last intercourse was higher among men than women. Also, a lifetime history of illicit drug consumption decreased the probability of condom use at last sexual intercourse by half. Among men, the use of illicit drugs doubled the probability of intercourse with a casual partner during the last year and tripled the probability of reported STI symptoms.</p> <p>Conclusion</p> <p>Drug consumption is associated with high-risk sexual behaviors and reported STI symptoms in a Lima shantytown after controlling for alcohol consumption level. Development of prevention programs for risky sexual behaviors, considering gender differences, is discussed.</p

A theoretical study on the formation of iodine oxide aggregates and monohydrates

Biotic and abiotic emissions of molecular iodine and iodocarbons from the sea or the ice surface and the intertidal zone to the coastal/polar marine boundary layer lead to the formation of iodine oxides, which subsequently nucleate forming iodine oxide particles (IOPs). Although the link between coastal iodine emissions and ultrafine aerosol bursts is well established, the details of the nucleation mechanism have not yet been elucidated. In this paper, results of a theoretical study of a range of potentially relevant aggregation reactions of different iodine oxides, as well as complexation with water molecules, are reported. Thermochemical properties of these reactions are obtained from high level ab initio correlated calculations including spin-orbit corrections. The results show that the nucleation path most likely proceeds through dimerisation of I2O4. It is also shown that water can hinder gas-to-particle conversion to some extent, although complexation with key iodine oxides does not remove enough of these to stop IOP formation. A consistent picture of this process emerges from the theoretical study presented here and the findings of a new laboratory study reported in the accompanying paper (Gomez Martin et al., 2013)

Modulation of vascular reactivity by perivascular adipose tissue (PVAT)

Purpose of Review: In this review we discuss the role of perivascular adipose tissue (PVAT) in the modulation of vascular contractility and arterial pressure, focusing on the role of the renin-angiotensin-aldosterone system and oxidative stress/inflammation. Recent Findings: PVAT possesses an relevant endocrine-paracrine activity, which may be altered in several pathophysiological and clinical conditions. During the last two decades it has been shown PVAT may modulate vascular reactivity. It has also been previously demonstrated that inflammation in adipose tissue may be implicated in vascular dysfunction. In particular, adipocytes secrete a number of adipokines with various functions, as well as several vasoactive factors, together with components of the renin-angiotensin system which may act at local or at systemic level. It has been shown that the anticontractile effect of PVAT is lost in obesity, probably as a consequence of the development of adipocyte hypertrophy, inflammation, and oxidative stress. Summary: Adipose tissue dysfunction is interrelated with inflammation and oxidative stress, thus contributing to endothelial dysfunction observed in several pathological and clinical conditions such as obesity and hypertension. Decreased local adiponectin level, macrophage recruitment and infiltration, and activation of renin-angiotensin-aldosterone system could play an important role in this regards