326,879 research outputs found
Doctor of Philosophy
dissertationIn the era of big data, many applications generate continuous online data from distributed locations, scattering devices, etc. Examples include data from social media, financial services, and sensor networks, etc. Meanwhile, large volumes of data can be archived or stored offline in distributed locations for further data analysis. Challenges from data uncertainty, large-scale data size, and distributed data sources motivate us to revisit several classic problems for both online and offline data explorations. The problem of continuous threshold monitoring for distributed data is commonly encountered in many real-world applications. We study this problem for distributed probabilistic data. We show how to prune expensive threshold queries using various tail bounds and combine tail-bound techniques with adaptive algorithms for monitoring distributed deterministic data. We also show how to approximate threshold queries based on sampling techniques. Threshold monitoring problems can only tell a monitoring function is above or below a threshold constraint but not how far away from it. This motivates us to study the problem of continuous tracking functions over distributed data. We first investigate the tracking problem on a chain topology. Then we show how to solve tracking problems on a distributed setting using solutions for the chain model. We studied online tracking of the max function on ""broom"" tree and general tree topologies in this work. Finally, we examine building scalable histograms for distributed probabilistic data. We show how to build approximate histograms based on a partition-and-merge principle on a centralized machine. Then, we show how to extend our solutions to distributed and parallel settings to further mitigate scalability bottlenecks and deal with distributed data
STATIC AND DYNAMIC BEHAVIOUR ASSESSMENT OF THE TRAJAN ARCH BY MEANS OF NEW MONITORING TECHNOLOGIES
An effective assessment of the static and dynamic structural behavior of historical monuments requires the development and validation of suitable adaptive structural models using high-quality experimental data acquired with an effectively continuous and distributed monitoring. Furthermore, the adaptive strategy allows an efficient evaluation of the health status and of the evolution along the time of a historical monument, providing relevant information to plan appropriate actions for its long-term preservation. The Trajan Arch in Benevento chosen as a case of study to develop and apply this new adaptive strategy in cultural heritage conservation. The paper, after a description of the innovative monitoring system, based on state-of-the-art mechanical sensors, presents and discusses the results of two tests, comparing the measurements with the predictions of an adaptive structural FEM model developed for the dynamical simulation of the Trajan Arch
MEDUSA: Scalable Biometric Sensing in the Wild through Distributed MIMO Radars
Radar-based techniques for detecting vital signs have shown promise for
continuous contactless vital sign sensing and healthcare applications. However,
real-world indoor environments face significant challenges for existing vital
sign monitoring systems. These include signal blockage in non-line-of-sight
(NLOS) situations, movement of human subjects, and alterations in location and
orientation. Additionally, these existing systems failed to address the
challenge of tracking multiple targets simultaneously. To overcome these
challenges, we present MEDUSA, a novel coherent ultra-wideband (UWB) based
distributed multiple-input multiple-output (MIMO) radar system, especially it
allows users to customize and disperse the into sub-arrays.
MEDUSA takes advantage of the diversity benefits of distributed yet wirelessly
synchronized MIMO arrays to enable robust vital sign monitoring in real-world
and daily living environments where human targets are moving and surrounded by
obstacles. We've developed a scalable, self-supervised contrastive learning
model which integrates seamlessly with our hardware platform. Each attention
weight within the model corresponds to a specific antenna pair of Tx and Rx.
The model proficiently recovers accurate vital sign waveforms by decomposing
and correlating the mixed received signals, including comprising human motion,
mobility, noise, and vital signs. Through extensive evaluations involving 21
participants and over 200 hours of collected data (3.75 TB in total, with 1.89
TB for static subjects and 1.86 TB for moving subjects), MEDUSA's performance
has been validated, showing an average gain of 20% compared to existing systems
employing COTS radar sensors. This demonstrates MEDUSA's spatial diversity gain
for real-world vital sign monitoring, encompassing target and environmental
dynamics in familiar and unfamiliar indoor environments.Comment: Preprint. Under Revie
Synthesis of decision making in a distributed intelligent personnel health management system on offshore oil platform
This paper proposes a methodological approach for the decision synthesis in a geographically distributed intelligent health management system for oil workers working in offshore industry. The decision-making methodology is based on the concept of a person-centered approach to managing the health and safety of personnel, which implies the inclusion of employees as the main component in the control loop. This paper develops a functional model of the health management system for workers employed on offshore oil platforms and implements it through three phased operations that is monitoring and assessing the health indicators and environmental parameters of each employee, and making decisions. These interacting operations combine the levels of a distributed intelligent health management system. The paper offers the general principles of functioning of a distributed intelligent system for managing the health of workers in the context of structural components and computing platforms. It presents appropriate approaches to the implementation of decision support processes and describes one of the possible methods for evaluating the generated data and making decisions using fuzzy pattern recognition. The models of a fuzzy ideal image and fuzzy real images of the health status of an employee are developed and an algorithm is described for assessing the deviation of generated medical parameters from the norm. The paper also compiles the rules to form the knowledge bases of a distributed intelligent system for remote continuous monitoring. It is assumed that embedding this base into the intelligent system architecture will objectively assess the trends in the health status of workers and make informed decisions to eliminate certain problem
- …