Sensory data is only meaningful if correctly associated with originating locations, e.g., in three-dimensional wireless sensor systems inside an aircraft cabin. Received signal strength is a cost-effective option to locate low-cost sensors due to its universal availability, but suffers from coarse ranging accuracy with multiplicative errors. This paper presents a new received signal strength-based approach to locating a large number of low-cost sensors given their possible three-dimensional installation points. Our approach achieves the accuracy which has not been achieved in the literature. The approach first cooperatively locates the sensors in the continuous three-dimensional spaces, then associates the continuous location estimates to the installation points, and finally refines the association with likelihood ascent search. A new convex relaxation-based optimization is designed for cooperative localization in continuous three-dimensional spaces. The Kuhn-Munkres algorithm is generalized for the association. Cramér-Rao Lower Bounds are derived to specify the local three-dimensional regions in which refinement is carried out to improve the final accuracy with little complexity overhead. The proposed approach is validated experimentally with signal strength measurements collected in a Fokker 100 passenger plane, achieves 100% accuracy in all experiments conducted, and outperforms state-of-the-art metaheuristics significantly with much shorter execution time. Note to Practitioners—This paper is motivated by a goal to realize various aircraft automation applications through three-dimensional localization and association of wireless sensors. For example, automatic identification of seat locations can be implemented efficiently with wireless sensors, which enables effortless re-association between control buttons in the seats and the corresponding functions after cabin refurbishment. Meanwhile, automatic detection of missing/misplaced safety equipment can be carried out to improve the efficiency of flight preparation. There currently lacks an received signal strength-based three-dimensional sensor association method in indoor environments. The theoretical framework proposed in this paper aims to utilize the readily available received signal strength measurements to associate Commercial-Off-The-Shelf sensors to their possible installation points. This approach avoids the requirement of labor-intensive fingerprinting effort and high-cost equipment. The proposed approach has been tested and evaluated using both synthetic data and real data collected in a passenger plane as a proof of concept.

Sensory data is only meaningful if correctly associated with originating locations. Received signal strength (RSS) is a cost-effective option to locate low-cost sensors due to its universal availability, but yet to be practical because of its coarse ranging accuracy with multiplicative errors. This paper presents a new RSS-based approach to the localization and association of a large number of low-cost sensors given their possible 3D installation locations. The approach addresses the mathematically challenging combinatorial optimization of association by first co-operatively locating the sensors in the continuous 3D spaces, then associating the continuous location estimates to the installation points, and finally refining the association with likelihood ascent search. A new convex relaxation-based optimization is designed for cooperative localization in continuous 3D spaces. The Kuhn-Munkres algorithm is generalized for the association. Cramer-Rao Lower Bounds are derived to specify the local 3D regions in which refinement is carried out to improve the final accuracy with little complexity overhead. The proposed approach is validated through both computer simulation and lab test. It achieves close-to-100% accuracy in all experiments conducted, and outperforms state-of-the-art metaheuristics significantly.

Radio connectivity in wireless sensor networks is highly intermittent due to unpredictable and time-varying noise and interference patterns in the environment. Because link qualities are not predictable prior to deployment, current deterministic solutions to unreliable links, such as increasing network density or transmission power, require overprovisioning of network resources and do not always improve reliability. We propose a new dual-radio network architecture to improve communication reliability in wireless sensor networks. Specifically, we show that radio transceivers operating at well-separated frequencies and spatially separated antennas offer robust communication, high link diversity, and better interference mitigation. We derive the optimal parameters for the dual-transceiver setup from frequency and space diversity in theory. We observe that frequency diversity holds the most benefits as long as the antennas are sufficiently separated to prevent coupling. Our experiments on an indoor/outdoor testbed confirm the theoretical predictions and show that radio diversity can significantly improve end-to-end delivery rates and network stability at only a small increase in energy cost over a single radio. Simulation experiments further validate the improvements in multiple topology configurations, but also reveal that the benefits of radio diversity are coupled to the number of available routing paths to the destination.

Critically examines a number of issues related to the management of emerging software technologies. Some working guidelines are provided. It is recommended that any management process used be measured and consistently analyzed to improve one's competitive edge. In the area of metrics for managing object technology, there is an almost total lack of information. The current focus of the Consortium for the Management of Emerging Software Technologies (COMSOFT) is an object-oriented technology and the related area of software reuse. The new environment must be implemented piecemeal and frequently structures and procedures must be implemented that are only operational bridges, because during the transition two operational methodologies and philosophies will exist.>