Critical Nodes Detection in IoT-Based Cyber-Physical Systems

The new generation of fast, small, and energy-efficient devices that can connect to the internet are already used for different purposes in healthcare, smart homes, smart cities, industrial automation, and entertainment. One of the main requirements in all kinds of cyber-physical systems is a reliable communication platform. In a wired or wireless network, losing some special nodes may disconnect the communication paths between other nodes. Generally, these nodes, which are called critical nodes, have many undesired effects on the network. The authors focus on three different problems. The first problem is finding the nodes whose removal minimizes the pairwise connectivity in the residual network. The second problem is finding the nodes whose removal maximizes the number of connected components. Finally, the third problem is finding the nodes whose removal minimizes the size of the largest connected component. All three problems are NP-Complete, and the authors provide a brief survey about the existing approximated algorithms for these problems.

Evaluating the Efficacy of Sustainability Initiatives in the Canadian Port Sector

Maritime ports are critical nodes in the Canadian resource-based economy that can have significant environmental impacts near coastal communities and marine ecosystems. To address these impacts, Canadian Port Authorities (CPAs) assess their environmental performance using the Green Marine Environmental Program (GMEP). Reliance on this program necessitates its evaluation as an effective initiative to address sustainability in its broader context. An analysis was performed to identify links between United Nations Sustainable Development Goals (UN SDG) targets relevant to the Canadian Port Sector and GMEP performance indicators. Results indicate that there are significant gaps in the GMEP, with only 14 of 36 relevant SDG targets directly linked to the program. Findings suggest either an expansion of the GMEP to incorporate these broader sustainability goals, or the development and inclusion of a new framework for CPAs to bridge gaps between the GMEP and SDG targets to improve sustainability in their maritime port operations.

Articulations of workplace precarity: Challenging the politics of segmentation in warehouse logistics

As critical nodes for global commodity flows, warehouses are an important example of segmented labour regimes which partition workers into groups with different conditions of security or its opposite, precarity. An emerging literature on warehouse work has tended to place segmentation in the context of managerial despotism based upon low wages, high labour turnover and job insecurity. However, the literature has, thus far, tended to pay comparatively less attention to workers’ collective resistance and its relationship to intra-labour divisions reproduced through segmentation. In refocusing attention to this problem, this article addresses the theoretical status of intra-labour groups, the nature of horizontal worker-to-worker relations, and their interaction with workers’ social identities and vertical capital–labour relations. It argues that the Gramscian concept of articulation provides the most promising frame for understanding these networked relations and for addressing how the politics of segmentation can be challenged by building common cause among divided workers.

Patent Analysis in the 5G Network

In recent years, 5G has been the focus of research and development in the telecom industry. This paper aims to understand the development trend and technical hot spots of 5G technology through the patent analysis and build a citation network at the assignee organization level. The workflow of the paper is divided into four steps: patent data collection and cleaning, patent overview analysis, network creation and analysis, O-I index analysis. This article collected the patent data from the United States patent and trademark office (USPTO). We understand the application trend, technical hot spots, and leading players in the 5G domain through the patent overview analysis. We comprehend the structure and characteristics of the network and critical nodes from network topology analysis. By using O-I index analysis, we learn the flow of 5G technology knowledge between the organizations. This paper provides a useful analytical model for the patent analysis and technological knowledge flow in a specific field, which can be applied to patent analysis in other fields.

Patent analysis in the 5G network

In recent years, 5G has been the focus of research and development in the telecom industry. This paper aims to understand the development trend and technical hot spots of 5G technology through the patent analysis and build a citation network at the assignee organization level. The workflow of the paper is divided into four steps: patent data collection and cleaning, patent overview analysis, network creation and analysis, O-I index analysis. This article collected the patent data from the United States patent and trademark office (USPTO). We understand the application trend, technical hot spots, and leading players in the 5G domain through the patent overview analysis. We comprehend the structure and characteristics of the network and critical nodes from network topology analysis. By using O-I index analysis, we learn the flow of 5G technology knowledge between the organizations. This paper provides a useful analytical model for the patent analysis and technological knowledge flow in a specific field, which can be applied to patent analysis in other fields.

Approaching the bi-objective critical node detection problem with a smart initialization-based evolutionary algorithm

Determining the critical nodes in a complex network is an essential computation problem. Several variants of this problem have emerged due to its wide applicability in network analysis. In this article we study the bi-objective critical node detection problem (BOCNDP), which is a new variant of the well-known critical node detection problem, optimizing two objectives at the same time: maximizing the number of connected components and minimizing the variance of their cardinalities. Evolutionary multi-objective algorithms (EMOA) are a straightforward choice to solve this type of problem. We propose three different smart initialization strategies which can be incorporated into any EMOA. These initialization strategies take into account the basic properties of the networks. They are based on the highest degree, random walk (RW) and depth-first search. Numerical experiments were conducted on synthetic and real-world network data. The three different initialization types significantly improve the performance of the EMOA.

PINC: Pickup Non-Critical Node Based k-Connectivity Restoration in Wireless Sensor Networks

A Wireless Sensor Network (WSN) is connected if a communication path exists among each pair of sensor nodes (motes). Maintaining reliable connectivity in WSNs is a complicated task, since any failure in the nodes can cause the data transmission paths to break. In a k-connected WSN, the connectivity survives after failure in any k-1 nodes; hence, preserving the k-connectivity ensures that the WSN can permit k-1 node failures without wasting the connectivity. Higher k values will increase the reliability of a WSN against node failures. We propose a simple and efficient algorithm (PINC) to accomplish movement-based k-connectivity restoration that divides the nodes into the critical, which are the nodes whose failure reduces k, and non-critical groups. The PINC algorithm pickups and moves the non-critical nodes when a critical node stops working. This algorithm moves a non-critical node with minimum movement cost to the position of the failed mote. The measurements obtained from the testbed of real IRIS motes and Kobuki robots, along with extensive simulations, revealed that the PINC restores the k-connectivity by generating optimum movements faster than its competitors.