The structure and dynamics of multilayer networks

In the past years, network theory has successfully characterized the interaction among the constituents of a variety of complex systems, ranging from biological to technological, and social systems. However, up until recently, attention was almost exclusively given to networks in which all components were treated on equivalent footing, while neglecting all the extra information about the temporal- or context-related properties of the interactions under study. Only in the last years, taking advantage of the enhanced resolution in real data sets, network scientists have directed their interest to the multiplex character of real-world systems, and explicitly considered the time-varying and multilayer nature of networks. We offer here a comprehensive review on both structural and dynamical organization of graphs made of diverse relationships (layers) between its constituents, and cover several relevant issues, from a full redefinition of the basic structural measures, to understanding how the multilayer nature of the network affects processes and dynamics.Comment: In Press, Accepted Manuscript, Physics Reports 201

Recent Trends and Innovations in Modelling City Logistics

AbstractThere are many challenges associated with moving goods within cities as urban areas become larger and elderly residents require more healthcare in their homes. Air quality is also impacted by urban freight vehicles. This paper presents a review of recent trends and innovations in modelling city logistics. New techniques for modelling city logistics developed in the areas of emissions, healthcare and mega-cities are outlined. This paper describes the formulation, solution methodologies and applications of these models

A digital twin study for immediate design / redesign of impellers and blades: part 1: CAD modelling and tool path simulation.

This paper presents a digital twining study conducted for an immediate design / redesign and manufacturing of on impellers and blades. It is by accomplished by developing (i) CAD automation methods, based on the standard modelling procedures and (ii) Manufacturing automation based on the 3/3 + 1/3 + 2/5 axis milling process. Initially, the CAD model of impeller / blade is created by utilizing the dimensional parameters obtained through standard design calculations / data. It is then parametrized and converted to an automated model through simple dimensional rules and geometric algorithms developed for the purpose. After this stage, the CAD model is analyzed for manufacturing automation where the process planning data comprising cutting tools, process parameters and setups are selected. Here, the tool paths are generated for 3/3 + 1/3 + 2/5 axis milling considering a CNC Vertical Machining Center (VMC) to digitally twin milling process. Both the CAD modelling and manufacturing process plans including tool path generation are captured through journaling and customized / improved using the Application Programmable Interface's (API's) to suit the present scope. In this paper, the first part on CAD modelling and manufacturing simulation methodologies are discussed through validating the digital twining concept in a virtual environment. The work is developed with the focus to help industries moving towards Industry 4.0 and requiring a constant design improvement in their products. It is by emphasizing the importance of digital twinning concept where a concurrent verification of design and manufacturing process can be achieved

Logistics Decisions in Descriptive Freight Transportation Models: A Review

The objective of this paper is to provide an inventory of approaches to descriptively (as opposed to normatively) model logistics decisions within the context of freight transport modelling. Rather than taking transport modelling frameworks as a starting point, as has been the case in the literature so far, we depart from a framework of logistics decisions. The framework is developed by combining elements of over a dozen existing frameworks from the supply chain management literature. Based on this comprehensive framework, we review freight modelling approaches from the literature. We find that freight modelling can be extended by taking into account previously uncovered areas of logistics decisions, such as those related to marketing or logistics systems forecasting and planning, as well as in areas that are well known from an optimization perspective but not from a descriptive perspective, such as routing and scheduling decisions. We conclude with a systematic listing of such areas, which can be used by researchers and transport modelling practitioners to develop further those transport models that take agent decision making as a starting point

Establishing a Network Planning Model of Urban-Rural Logistics Based on Hub-and-Spoke Network

The demand of urban-rural logistics (URL) has scattered characteristics, which result in difficulty in applying the existing network planning model of URL. A network planning model of URL was established to create a planning scheme that can meet scattered logistics demands. This model is combined with the hub-and-spoke network modeling method, including the hybrid hub-and-spoke network, single-assignment, and hub node quantity constraints. For this model, the minimum total cost was taken as the objective function, whereas the hub node location, assignment relationship, and direct path planning were taken as decision variables. Moreover, the model was solved using the tabu search algorithm. Finally, the model was applied to the network planning example of URL in Nanjing-Zhenjiang-Yangzhou, China. Results indicate that the optimal hub location and quantity, the optimal distribution path, and the most reasonable straight-through route can be determined by the hub-and-spoke network planning model of URL. In addition, the URL network shows the form of two-level hybrid hub-and-spoke with multi hubs and single distribution, in which the scattered demands can be concentrated on a few hub nodes and axes. Findings indicate that the network planning problem of URL under scattered demands can be effectively solved by the new model

The Human Body as a Super Network: Digital Methods to Analyze the Propagation of Aging

Biological aging is a complex process involving multiple biological processes. These can be understood theoretically though considering them as individual networks—e.g., epigenetic networks, cell-cell networks (such as astroglial networks), and population genetics. Mathematical modeling allows the combination of such networks so that they may be studied in unison, to better understand how the so-called “seven pillars of aging” combine and to generate hypothesis for treating aging as a condition at relatively early biological ages. In this review, we consider how recent progression in mathematical modeling can be utilized to investigate aging, particularly in, but not exclusive to, the context of degenerative neuronal disease. We also consider how the latest techniques for generating biomarker models for disease prediction, such as longitudinal analysis and parenclitic analysis can be applied to as both biomarker platforms for aging, as well as to better understand the inescapable condition. This review is written by a highly diverse and multi-disciplinary team of scientists from across the globe and calls for greater collaboration between diverse fields of research

The Human Body as a Super Network: Digital Methods to Analyze the Propagation of Aging

Biological aging is a complex process involving multiple biological processes. These can be understood theoretically though considering them as individual networks—e.g., epigenetic networks, cell-cell networks (such as astroglial networks), and population genetics. Mathematical modeling allows the combination of such networks so that they may be studied in unison, to better understand how the so-called “seven pillars of aging” combine and to generate hypothesis for treating aging as a condition at relatively early biological ages. In this review, we consider how recent progression in mathematical modeling can be utilized to investigate aging, particularly in, but not exclusive to, the context of degenerative neuronal disease. We also consider how the latest techniques for generating biomarker models for disease prediction, such as longitudinal analysis and parenclitic analysis can be applied to as both biomarker platforms for aging, as well as to better understand the inescapable condition. This review is written by a highly diverse and multi-disciplinary team of scientists from across the globe and calls for greater collaboration between diverse fields of research