Layer degradation triggers an abrupt structural transition in multiplex networks

Network robustness is a central point in network science, both from a theoretical and a practical point of view. In this paper, we show that layer degradation, understood as the continuous or discrete loss of links' weight, triggers a structural transition revealed by an abrupt change in the algebraic connectivity of the graph. Unlike traditional single layer networks, multiplex networks exist in two phases, one in which the system is protected from link failures in some of its layers and one in which all the system senses the failure happening in one single layer. We also give the exact critical value of the weight of the intra-layer links at which the transition occurs for continuous layer degradation and its relation to the value of the coupling between layers. This relation allows us to reveal the connection between the transition observed under layer degradation and the one observed under the variation of the coupling between layers.Comment: 8 pages, and 8 figures in Revtex style. Submitted for publicatio

Decentralized Multi-Floor Exploration by a Swarm of Miniature Robots Teaming with Wall-Climbing Units

In this paper, we consider the problem of collectively exploring unknown and dynamic environments with a decentralized heterogeneous multi-robot system consisting of multiple units of two variants of a miniature robot. The first variant-a wheeled ground unit-is at the core of a swarm of floor-mapping robots exhibiting scalability, robustness and flexibility. These properties are systematically tested and quantitatively evaluated in unstructured and dynamic environments, in the absence of any supporting infrastructure. The results of repeated sets of experiments show a consistent performance for all three features, as well as the possibility to inject units into the system while it is operating. Several units of the second variant-a wheg-based wall-climbing unit-are used to support the swarm of mapping robots when simultaneously exploring multiple floors by expanding the distributed communication channel necessary for the coordinated behavior among platforms. Although the occupancy-grid maps obtained can be large, they are fully distributed. Not a single robotic unit possesses the overall map, which is not required by our cooperative path-planning strategy.Comment: Accepted for publication in IEEE-MRS 2019, Rutgers University, New Brunswick (NJ), US

Heterogeneous Swarms for Maritime Dynamic Target Search and Tracking

Current strategies employed for maritime target search and tracking are primarily based on the use of agents following a predetermined path to perform a systematic sweep of a search area. Recently, dynamic Particle Swarm Optimization (PSO) algorithms have been used together with swarming multi-robot systems (MRS), giving search and tracking solutions the added properties of robustness, scalability, and flexibility. Swarming MRS also give the end-user the opportunity to incrementally upgrade the robotic system, inevitably leading to the use of heterogeneous swarming MRS. However, such systems have not been well studied and incorporating upgraded agents into a swarm may result in degraded mission performances. In this paper, we propose a PSO-based strategy using a topological k-nearest neighbor graph with tunable exploration and exploitation dynamics with an adaptive repulsion parameter. This strategy is implemented within a simulated swarm of 50 agents with varying proportions of fast agents tracking a target represented by a fictitious binary function. Through these simulations, we are able to demonstrate an increase in the swarm's collective response level and target tracking performance by substituting in a proportion of fast buoys.Comment: Accepted for IEEE/MTS OCEANS 2020, Singapor

A production control support system based on the concept of an artificial pseudo neural network

PURPOSE: The goal of the paper is to present the concept of a pseudo-neural network developed for production control in an industrial enterprise that produces complex products under discrete production conditions. This paper contains an attempt to use the theoretical basis of artificial neural networks to build a specialized tool. This tool is called a pseudo-network.DESIGN/METHODOLOGY/APPROACH: It is based not on the whole of the theory of artificial neural networks but only on the targeted elements selected for it. The selection criterion is the use of an artificial neural pseudo-network to control production.FINDINGS: The concept of artificial pseudo neural network is fully presented in previous works by the authors.PRACTICAL IMPLICATIONS: The network is part of the production planning and control system. In this system, the network acts as a subsystem responsible for production control. It cooperates with the production planning subsystem from which it periodically downloads the data on production task covering the assortment of manufactured products, production programs of individual assortment items, production start and end dates as well as its updates. In turn, it reports to the production planning subsystem about the progress of the implementation of the launched production task.ORIGINALITY/VALUE: The presented approach is original and can be developed to meet requirements of various production systems. It has both cognitive and utilitarian potential.peer-reviewe

Evaluation of knowledge flow from developed to developing countries in small satellite collaborative projects: the case of Algeria

Technology transfer involves the flow of knowledge from technology developers or possessors to technology acquirers that benefit from the knowledge. This article proposes a model for the evaluation of knowledge flow in complex technology transfer projects from developed to developing countries. The proposed knowledge flow model is built by combining the concepts of knowledge viscosity and velocity with the concepts of architectural and component knowledge. The model rests on the idea that the transfer of knowledge to resource-limited organizations such as those in developing countries requires a balance between viscosity and velocity on one hand and between architectural and component knowledge on the other. The knowledge flow model has been tested on data sourced from three Earth-observation small satellite collaborative projects leveraged by Algeria to acquire small satellite technology from abroad and build local capability. The implementation of the model revealed that the collaborative projects enabled only the acquisition of a shallow form of architectural knowledge detached from the local environment. The findings are reflective of the limitations of the collaborative projects mechanism and the challenge faced by the technology acquirer to strike the appropriate component/architectural and viscosity/velocity balance

Enhanced Gravity Model of Trade: Reconciling Macroeconomic and Network Models

The structure of the International Trade Network (ITN), whose nodes and links represent world countries and their trade relations, respectively, affects key economic processes worldwide, including globalization, economic integration, industrial production, and the propagation of shocks and instabilities. Characterizing the ITN via a simple yet accurate model is an open problem. The traditional Gravity Model (GM) successfully reproduces the volume of trade between connected countries, using macroeconomic properties, such as GDP, geographic distance, and possibly other factors. However, it predicts a network with complete or homogeneous topology, thus failing to reproduce the highly heterogeneous structure of the ITN. On the other hand, recent maximum entropy network models successfully reproduce the complex topology of the ITN, but provide no information about trade volumes. Here we integrate these two currently incompatible approaches via the introduction of an Enhanced Gravity Model (EGM) of trade. The EGM is the simplest model combining the GM with the network approach within a maximum-entropy framework. Via a unified and principled mechanism that is transparent enough to be generalized to any economic network, the EGM provides a new econometric framework wherein trade probabilities and trade volumes can be separately controlled by any combination of dyadic and country-specific macroeconomic variables. The model successfully reproduces both the global topology and the local link weights of the ITN, parsimoniously reconciling the conflicting approaches. It also indicates that the probability that any two countries trade a certain volume should follow a geometric or exponential distribution with an additional point mass at zero volume

Proceedings of the 9th Arab Society for Computer Aided Architectural Design (ASCAAD) international conference 2021 (ASCAAD 2021): architecture in the age of disruptive technologies: transformation and challenges.

The ASCAAD 2021 conference theme is Architecture in the age of disruptive technologies: transformation and challenges. The theme addresses the gradual shift in computational design from prototypical morphogenetic-centered associations in the architectural discourse. This imminent shift of focus is increasingly stirring a debate in the architectural community and is provoking a much needed critical questioning of the role of computation in architecture as a sole embodiment and enactment of technical dimensions, into one that rather deliberately pursues and embraces the humanities as an ultimate aspiration