Breadcrumb systems (BCS) have been proposed to aid firefighters inside buildings by communicating their physiological parameters to base stations outside the buildings. In this paper, we describe the design, implementation and evaluation of an automatic and robust breadcrumb system for firefighter applications. Our solution includes a breadcrumb dispenser with an optimized link estimator that is used to decide when to deploy breadcrumbs to maintain reliable wireless connectivity. The solution includes accounting for realities of buildings and dispensing such as the height difference between where the dispenser is worn and the floor where the dispensed nodes are found. We also include adaptive power management to maintain link quality over time.Experimental results from our study show that compared to the state of the art solution [14], our breadcrumb system achieves 200% link redundancy with only 23% additional deployed nodes. Our deployed crumb-chain can achieve 90% probability of end-to-end connectivity when one node fails in the crumb-chain and over 50% probability of end-to-end connectivity when up to 3 nodes fail in the crumb-chain. In addition, by applying adaptive transmission power control at each node after the crumb-chain deployment, we solve the link quality variation problem by avoiding significant variations in packet reception ratio (PRR) and maintain PRR of over 90% at the link level.

The renewable electricity-driven electrocatalytic oxidation of biomass represents a pathway to produce value-added chemicals from waste biomass such as glycerol (a byproduct of industrial biodiesel production). However, it remains difficult to design an efficient electrocatalyst with explicit structure–property relationships. Herein, we report a single-atom bismuth (Bi)-doping strategy to endow Co3O4 with enhanced activity and selectivity toward electrocatalytic glycerol oxidation reaction (GOR). Experimental characterizations and theoretical calculations reveal that single-atom Bi substitutes cobalt at octahedral sites (CoOh 3+) in Co3O4, facilitating the generation of reactive hydroxyl species (OH*) at adjacent tetrahedral Co sites (CoTd 2+). Mechanism studies demonstrate that OH* accelerates the oxidation of hydroxyl groups and carbon–carbon (C–C) bond cleavage, achieving GOR activity (400 mA cm–2 at 1.446 V vs reversible hydrogen electrode, RHE) and high faradaic efficiency of formate (97.05 ± 2.55%). Our study shows a promising way to promote the electro-oxidation activity of spinel oxides for biomass valorization by a single-atom doping strategy.

This paper describes a novel group based programming abstraction called a 'Bundle' for cyber physical systems (CPS). Similar to other programming abstractions, a Bundle creates logical collections of sensing devices. However, previous abstractions were focused on wireless sensor networks (WSN) and did not address key aspects of CPS. Bundles elevate the programming domain from a single WSN to complex systems of systems by allowing the programming of applications involving multiple CPSs that are controlled by different administrative domains and support mobility both within and across CPSs. Bundles can seamlessly group not only sensors, but also actuators which constitute an important part of CPS. Bundles support heterogeneous devices, such as motes, PDAs, laptops and actuators according to the applications' requirements. They allow different applications to simultaneously use the same sensors and actuators. Bundles facilitate feedback control mechanisms by dynamic membership update and requirements reconfiguration based on feedback from the current members. The Bundle abstraction is implemented in Java which ensures ease and conciseness of programming. We present the design and implementation details of Bundles as well as a performance evaluation using 32 applications written with Bundles. This set includes across-network applications that have sophisticated sensing and actuation logic, mobile nodes that are heterogeneous, and feedback control mechanisms. Each of these applications is programmed in less than 60 lines of code.

This paper describes the design and implementation of a pervasive computing framework, named Physicalnet. Essentially, Physicalnet is a generic paradigm for managing and programming world-wide distributed heterogeneous sensor and actuator resources in a multi-user and multi-network environment. Using a four-tier light-weight service oriented architecture, Physicalnet enables global uniform access to heterogeneous resources and decouples applications from particular resources, locations and networks. Through a negotiator module, it allows a large number of applications to concurrently execute on the same resources and to span multiple physical networks and logical administrative domains. By providing a fine-grained usebased access rights control and conflict resolution mechanism, Physicalnet not only ensures owners having total control of sharing and protecting their resources, but also dramatically increases the number of applications that can concurrently execute on the devices. Furthermore, Physicalnet supports resource dynamic location-aware mobility, application run-time reconfigurability and on-the-fly access rights specification. To quantify the performance, we evaluate Physicalnet based on memory usage, the number of concurrent applications, and dynamic responsiveness. The results show Physicalnet has excellent performance, but low overheads.