DADC: A Novel Duty-cycling Scheme for IEEE 802.15.4 Cluster-tree-based IoT Applications

The IEEE 802.15.4 standard is one of the widely adopted specifications for realizing different applications of the Internet of Things. It defines several physical layer options and Medium Access Control (MAC) sub-layer for devices with low-power operating at low data rates. As devices implementing this standard are primarily battery-powered, minimizing their power consumption is a significant concern. Duty-cycling is one such power conserving mechanism that allows a device to schedule its active and inactive radio periods effectively, thus preventing energy drain due to idle listening. The standard specifies two parameters, beacon order and superframe order, which define the active and inactive period of a device. However, it does not specify a duty-cycling scheme to adapt these parameters for varying network conditions. Existing works in this direction are either based on superframe occupation ratio or buffer/queue length of devices. In this article, the particular limitations of both the approaches mentioned above are presented. Later, a novel duty-cycling mechanism based on MAC parameters is proposed. Also, we analyze the role of synchronization schemes in achieving efficient duty-cycles in synchronized cluster-tree network topologies. A Markov model has also been developed for the MAC protocol to estimate the delay and energy consumption during frame transmission.

Percolation Distribution in Small-World Quantum Networks

Quantum networks have good prospects for applications in the future. Compared with classical networks, small-world quantum networks have some interesting properties. The topology of the network can be changed through entanglement exchange operations, and different network topologies will result in different percolation thresholds when performing entanglement percolation. A lower percolation threshold means that quantum networks require fewer minimum resources for communication. Since a shared singlet between two nodes can still be a limitation, concurrency percolation theory (ConPT) can be used to relax the condition. In this paper, we investigate how entanglement distribution is performed in small-world quantum networks to ensure that nodes in the network can communicate with each other by establishing communication links through entanglement swapping. Any node can perform entanglement swapping on only part of the connected edges, which can reduce the influence of each node in the network during entanglement swapping. In addition, the ConPT method is used to reduce the percolation threshold even further, thus obtaining a better network structure and reducing the resources required.

Analysis of Security Vulnerability Levels of In-Vehicle Network Topologies Applying Graph Representations

This article investigates cybersecurity issues related to in-vehicle communication networks. In-vehicle communication network security is evaluated based on the protection characteristics of the network components and the topology of the network. The automotive communication network topologies are represented as undirected weighted graphs, and their vulnerability is estimated based on the specific characteristics of the generated graph. Thirteen different vehicle models have been investigated to compare the vulnerability levels of the in-vehicle network using the Dijkstra's shortest route algorithm. An important advantage of the proposed method is that it is in accordance with the most relevant security evaluation models. On the other hand, the newly introduced approach considers the Secure-by-Design concept principles.

Is Network Structure Important for Protest Mobilization? Findings from Agent-Based Modeling

In recent decades, the focus of civic engagement research has shifted towards studying social environments’ effects on individuals’ decisions on whether to participate in a given activity or not. Online communication has been increasingly influencing the scale of social environments as well as the features of both online and offline interpersonal communications. Surely, then, individuals’ decisions concerning protest mobilization are bound to be affected by network properties. Using a series of ABM models with different network structures, we try to identify the structural factors of networks that can influence individuals who are deciding whether to join a protest. The established research in this field traditionally points to two structural factors: network topology and homophily. To our knowledge, however, the literature has not considered two above-mentioned structural factors in combination. In other words, their joint influence on protest mobilization has not been tested. To fill this research gap, we combine several network topologies with enabled/disabled homophily and examine how the combination influences protest turnout and survival. Numerical experiments show that homophily is positively associated with the survival of the protest, but negatively with its size for any network topology. Since we infer this conclusion from a theory-based computational model, we also propose how empirical testing can be conducted. Acknowledgments: This research is supported by the Russian Science Foundation under grant no. 20-18-00274, HSE University.

Fluid-Flow Approximation in the Analysis of Vast Energy-Aware Networks

The paper addresses two issues: (i) modeling dynamic flows transmitted in vast TCP/IP networks and (ii) modeling the impact of energy-saving algorithms. The approach is based on the fluid-flow approximation, which applies first-order differential equations to analyze the evolution of queues and flows. We demonstrate that the effective implementation of this method overcomes the constraints of storing large data in numerical solutions of transient problems in vast network topologies. The model is implemented and executed directly in a database system. It can analyze transient states in topologies of more than 100,000 nodes, i.e., the size which was not considered until now. We use it to investigate the impact of an energy-saving algorithm on the performance of a vast network. We find that it reduces network congestion and save energy costs but significantly lower network throughput.

Leader-following Synchronization Control of Multiple Electrohydraulic Actuators Under Switching Network Topologies

A leader-following quasi-synchronization control is proposed in multiple electrohydraulic actuators (MEHAs) under different switching network topologies to guarantee the follower electrohydraulic actuators (EHAs) tracking the leader motion. Firstly, each electro-hydraulic actuator (EHA) has a 3-order nonlinear dynamics with unknown external load. Then by using Lie derivative technique, the MEHAs nonlinear models with $n+1$ nodes are feedback linearized for convenient control design. Furthermore, the leader node is constructed as a virtual simulation model to be stabilized by PI controller. Meanwhile, a quasi-synchronized controller together with a disturbance observer is designed by LMI and Lyapunov techniques to guarantee that the synchronization errors between the n follower nodes and the leader node 0 are uniformly ultimate boundaries. Finally, the effectiveness of the leader-following quasi-synchronized controller is verified by a MEHAs experimental bench with 3 EHAs under switching network topologies.