1. Networks behind the morphology and structural design of living systemsMarko Gosak, Marko Milojević, Maja Duh, Kristijan Skok, Matjaž Perc, 2022, review article Abstract: Technological advances in imaging techniques and biometric data acquisition have enabled us to apply methods of network science to study the morphology and structural design of organelles, organs, and tissues, as well as the coordinated interactions among them that yield a healthy physiology at the level of whole organisms. We here review research dedicated to these advances, in particular focusing on networks between cells, the topology of multicellular structures, neural interactions, fluid transportation networks, and anatomical networks. The percolation of blood vessels, structural connectivity within the brain, the porous structure of bones, and relations between different anatomical parts of the human body are just some of the examples that we explore in detail. We argue and show that the models, methods, and algorithms developed in the realm of network science are ushering in a new era of network-based inquiry into the morphology and structural design of living systems in the broadest possible terms. We also emphasize that the need and applicability of this research is likely to increase significantly in the years to come due to the rapid progress made in the development of bioartificial substitutes and tissue engineering.
Keywords: network, morphology, structural properties, statistical physics
Published in DKUM: 17.09.2024; Views: 0; Downloads: 0 |
2. |
3. |
4. Synchronization in simplicial complexes of memristive Rulkov neuronsMahtab Mehrabbeik, Sajad Jafari, Matjaž Perc, 2023, original scientific article Abstract: Simplicial complexes are mathematical constructions that describe higher-order interactions within the interconnecting elements of a network. Such higher-order interactions become increasingly significant in neuronal networks since biological backgrounds and previous outcomes back them. In light of this, the current research explores a higher-order network of the memristive Rulkov model. To that end, the master stability functions are used to evaluate the synchronization of a network with pure pairwise hybrid (electrical and chemical) synapses alongside a network with two-node electrical and multi-node chemical connections. The findings provide good insight into the impact of incorporating higher-order interaction in a network. Compared to two-node chemical synapses, higher-order interactions adjust the synchronization patterns to lower multi-node chemical coupling parameter values. Furthermore, the effect of altering higher-order coupling parameter value on the dynamics of neurons in the synchronization state is researched. It is also shown how increasing network size can enhance synchronization by lowering the value of coupling parameters whereby synchronization occurs. Except for complete synchronization, cluster synchronization is detected for higher electrical coupling strength values wherein the neurons are out of the completed synchronization state.
Keywords: simplicial complex, higher-order network, memristive Rulkov, synchronization, cluster synchronization
Published in DKUM: 11.09.2024; Views: 37; Downloads: 2
 Full text (2,78 MB)
This document has many files! More... |
5. Most influential feature form for supervised learning in voltage sag source localizationYounes Mohammadi, Boštjan Polajžer, Roberto Chouhy Leborgne, Davood Khodadad, 2024, original scientific article Keywords: voltage sag (dip), source localization, supervised and unsupervised learning, convolutional neural network, time-sample-based features
Published in DKUM: 23.08.2024; Views: 65; Downloads: 4
Full text (15,94 MB) |
6. Exploring an infrastructure investment methodology to risk mitigation from rail hazardous materials shipmentsAli Vaezi, Manish Verma, 2021, original scientific article Abstract: Railroad is one of the primary modes to transport hazardous materials (hazmat) in North America. For instance, Canadian railroads carried around 50 million tons of hazmat in 2018. Given the inherent danger of trains carrying hazmat, this study aimed at exploring a novel way towards mitigation of the associated risk. This study sought to investigate whether proper rail track infrastructure investment can mitigate the risk from hazmat shipments. To this end, a methodology was developed and then applied to the Canadian railroad network. The proposed three-step methodology captured the differing perspectives of rail carriers and regulatory agencies, and entailed (1) ascertaining the risk-level of various yards and links in the given railroad network, (2) specifying potential candidates for infrastructure investment, and (3) finding the optimum set of investment decisions. The proposed methodology was then applied to the Canadian railroad network to demonstrate that significant risk-reduction can beachieved by adding alternative rail-links around the riskiest locations (i.e. the network hot-spots), and also to show that risk-reduction function is non-linear with non-monotonous behavior. The study showed the possibility of significant hazmat risk reduction through alternative rail-links that could take traffic away from the network hot-spots. The methodology and the resultsfrom the Canadian case can be used by railroad companies and policy makers to estimate the value of potentially risk-reducinginfrastructure investments.
Keywords: risk mitigation, railroad network, hazardous materials, infrastructure investment, optimization, transportation safety
Published in DKUM: 23.08.2024; Views: 61; Downloads: 3
Full text (1,85 MB)
This document has many files! More... |
7. Multi-criteria decision analysis of supply chain practices and firms performance in NigeriaBilqis Bolanle Amole, Sulaimon Olanrewaju Adebiyi, Olamilekan Gbenga Oyenuga, 2021, original scientific article Abstract: Companies are facing numerous pressures and challenges in order to be competitive in the market and meet the requirements of their customers which require an improvement in the supply chain practices of the firms to be more effective and efficient for sustainable competitive advantage. This study examines the use of a multi-criteria decision making method using analytic network process (ANP) to estimate the how supply chain activities of the selected manufacturing firms’ influences its firm performance in other to enhance the satisfaction of customers. The population of the study is the manufacturing firms quoted in the Nigeria stock exchange. An ANP-based questionnaire was administered to Managers of selected manufacturing firms for pairwise comparison of supply chain factors relative influences and dependencies on their customers. A nonlinear network model was built to capture all the factors of supply chain practices and firms performance into clusters, nodes and dependences for the purpose of estimating various influences supply chain practices on the performance of the various companies studied. Data collected were analysed using software of Super decision 3.0 version. The results revealed factors of supply chain practices that have a great connection with one another and strong relationship indicating that without the implementing the key factors of supply chain there would not be a significant improvement in the performance of the organisation which will also affects the desire of the customers. The ANP model has helped to show the interdependencies and feedback among the various factors of practices of supply chain to augment the level of performance of the firms.
Keywords: analytical network process, supply chain, strategic supplier partnership, supply chain integration, outsourcing, customer relationship management
Published in DKUM: 23.08.2024; Views: 74; Downloads: 2
Full text (1,18 MB)
This document has many files! More... |
8. Architecture of the health system as an enabler of better wellbeingTimotej Jagrič, Štefan Bojnec, Christine Elisabeth Brown, Vita Jagrič, 2023, original scientific article Abstract: ntroduction: Health systems worldwide have heterogenous capacities and financing characteristics. No clear empirical evidence is available on the possible outcomes of these characteristics for population wellbeing.
Aim: The study aims to provide empirical insight into health policy alternatives to support the development of health system architecture to improve population wellbeing.
Method and results: We developed an unsupervised neural network model to cluster countries and used the Human Development Index to derive a wellbeing model. The results show that no single health system architecture is associated with a higher level of population wellbeing. Strikingly, high levels of health expenditure and physical health capacity do not guarantee a high level of population wellbeing and different health systems correspond to a certain wellbeing level.
Conclusions: Our analysis shows that alternative options exist for some health system characteristics. These can be considered by governments developing health policy priorities.
Keywords: population wellbeing, health system capacity, public health system, health policy, neural network
Published in DKUM: 19.07.2024; Views: 186; Downloads: 5
Full text (3,01 MB)
This document has many files! More... |
9. Why are there six degrees of separation in a social network?I. Samoylenko, D. Aleja, E. Primo, Karin Alfaro-Bittner, E. Vasilyeva, K. Kovalenko, D. Musatov, A. M. Raigorodskii, R. Criado, M. Romance, David Papo, Matjaž Perc, B. Barzel, Stefano Boccaletti, 2023, original scientific article Abstract: A wealth of evidence shows that real-world networks are endowed with the small-world property, i.e., that the maximal distance between any two of their nodes scales logarithmically rather than linearly with their size. In addition, most social networks are organized so that no individual is more than six connections apart from any other, an empirical regularity known as the six degrees of separation. Why social networks have this ultrasmall-world organization, whereby the graph’s diameter is independent of the network size over several orders of magnitude, is still unknown. We show that the “six degrees of separation” is the property featured by the equilibrium state of any network where individuals weigh between their aspiration to improve their centrality and the costs incurred in forming and maintaining connections. We show, moreover, that the emergence of such a regularity is compatible with all other features, such as clustering and scale-freeness, that normally characterize the structure of social networks. Thus, our results show how simple evolutionary rules of the kind traditionally associated with human cooperation and altruism can also account for the emergence of one of the most intriguing attributes of social networks.
Keywords: degree distribution, network evolution, complex network, small-world network, social physics
Published in DKUM: 16.07.2024; Views: 111; Downloads: 4
Full text (876,16 KB)
This document has many files! More... |
10. Universality of political corruption networksAlvaro F. Martins, Bruno R. da Cunha, Quentin S. Hanley, Sebastián Gonçalves, Matjaž Perc, Haroldo V. Ribeiro, 2022, original scientific article Abstract: Corruption crimes demand highly coordinated actions among criminal agents to succeed. But research dedicated to corruption networks is still in its infancy and indeed little is known about the properties of these networks. Here we present a comprehensive investigation of corruption networks related to political scandals in Spain and Brazil over nearly three decades. We show that corruption networks of both countries share universal structural and dynamical properties, including similar degree distributions, clustering and assortativity coefficients, modular structure, and a growth process that is marked by the coalescence of network components due to a few recidivist criminals. We propose a simple model that not only reproduces these empirical properties but reveals also that corruption networks operate near a critical recidivism rate below which the network is entirely fragmented and above which it is overly connected. Our research thus indicates that actions focused on decreasing corruption recidivism may substantially mitigate this type of organized crime.
Keywords: corruption, network, politics, universality, social physics
Published in DKUM: 15.07.2024; Views: 119; Downloads: 7
Full text (7,26 MB)
This document has many files! More... |
