Open Standard Development Platforms for Distributed Sensor Networks

In the development of distributed security sensor networks a large variety of prototype systems have been implemented and tested. However these systems tend to be developer specific and require substantial overhead in demonstrating more than one application. To bridge the gap between embedded, networked systems and desktop simulation environments, systems are necessary which are easily deployable and allow extended operation of distributed sensor networks, while allowing the flexibility to quickly test and evaluate a variety of operational algorithms. To enable fast optimization by leveraging the widest development community, open standards for such a portable development system are desired. An open development system allows individual developers and small groups to focus on and optimize specific aspects of a distributed sensor network within realistic deployment constraints, prior to complete integration and deployment of a system within a specific application. By providing an embedded sensor and processing platform with integrated wired and wireless networking, a modular software suite separating access and control of individual processes, and open APIs, algorithm development and software optimization can be greatly accelerated and more robustly tested. To meet the unique needs of distributed sensor network applications, additional separation must be provided between the access to various subsystems, for example real-time embedded control versus tasks with less stringent timing requirements. An open platform that separates these requirements allows developers to accelerate testing and development of application

Methods for scalable self-assembly of ad hoc wireless sensor networks

Abstract—In distributed wireless sensing applications such as unattended ground sensor systems, remote planetary exploration, and condition-based maintenance, where the deployment site is remote and/or the scale of the network is large, individual emplacement and configuration of the sensor nodes is difficult. Hence, network self-assembly and continuous network self-organization during the lifetime of the network in a reliable, efficient, and scalable manner are crucial for successful deployment and operation of such networks. This paper provides an overview of the concept of network self-assembly for ad hoc wireless sensor networks at the link layer, with descriptions of results from implementation of a novel network formation mechanism for wireless unattended ground sensor applications using a multicluster hierarchical topology and a novel dual-radio architecture. Index Terms—Distributed networks, wireless communication, protocol architecture, access schemes, sensor networks, ad hoc networks.

Energy-aware Networked Embedded Systems for Tactical Unattended Ground Sensors

A system architecture, and a hardware implementation leveraging the architecture, has been developed for energy-aware, networked, embedded systems designed for use in tactical unattended ground sensor (UGS) applications. This modular system architecture is designed around a flexible bus design that meets the needs for low-power embedded systems, incorporating support for 32-bit inter-module data transfers, module synchronization, power control, and power distribution. A Linux-based software framework operating on the main system processor has been developed to provide application developers with the ability to easily leverage the hardware functionality of the system. The low-power design methods employed in the system design are discussed along with a system implementation using these methods

Risk of COVID-19 after natural infection or vaccinationResearch in context

Summary: Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health

Risk of COVID-19 after natural infection or vaccinationResearch in context

Background: While vaccines have established utility against COVID-19, phase 3 efficacy studies have generally not comprehensively evaluated protection provided by previous infection or hybrid immunity (previous infection plus vaccination). Individual patient data from US government-supported harmonized vaccine trials provide an unprecedented sample population to address this issue. We characterized the protective efficacy of previous SARS-CoV-2 infection and hybrid immunity against COVID-19 early in the pandemic over three-to six-month follow-up and compared with vaccine-associated protection. Methods: In this post-hoc cross-protocol analysis of the Moderna, AstraZeneca, Janssen, and Novavax COVID-19 vaccine clinical trials, we allocated participants into four groups based on previous-infection status at enrolment and treatment: no previous infection/placebo; previous infection/placebo; no previous infection/vaccine; and previous infection/vaccine. The main outcome was RT-PCR-confirmed COVID-19 >7–15 days (per original protocols) after final study injection. We calculated crude and adjusted efficacy measures. Findings: Previous infection/placebo participants had a 92% decreased risk of future COVID-19 compared to no previous infection/placebo participants (overall hazard ratio [HR] ratio: 0.08; 95% CI: 0.05–0.13). Among single-dose Janssen participants, hybrid immunity conferred greater protection than vaccine alone (HR: 0.03; 95% CI: 0.01–0.10). Too few infections were observed to draw statistical inferences comparing hybrid immunity to vaccine alone for other trials. Vaccination, previous infection, and hybrid immunity all provided near-complete protection against severe disease. Interpretation: Previous infection, any hybrid immunity, and two-dose vaccination all provided substantial protection against symptomatic and severe COVID-19 through the early Delta period. Thus, as a surrogate for natural infection, vaccination remains the safest approach to protection. Funding: National Institutes of Health