RESOURCE AWARE SELECTION OF USER GENERATED CONTENT IN CONSTRAINED MOBILE NETWORKS

Ph.DDOCTOR OF PHILOSOPH

Seamless Positioning and Navigation in Urban Environment

L'abstract è presente nell'allegato / the abstract is in the attachmen

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin

A survey on reconfigurable intelligent surfaces: wireless communication perspective

Using reconfigurable intelligent surfaces (RISs) to improve the coverage and the data rate of future wireless networks is a viable option. These surfaces are constituted of a significant number of passive and nearly passive components that interact with incident signals in a smart way, such as by reflecting them, to increase the wireless system's performance as a result of which the notion of a smart radio environment comes to fruition. In this survey, a study review of RIS-assisted wireless communication is supplied starting with the principles of RIS which include the hardware architecture, the control mechanisms, and the discussions of previously held views about the channel model and pathloss; then the performance analysis considering different performance parameters, analytical approaches and metrics are presented to describe the RIS-assisted wireless network performance improvements. Despite its enormous promise, RIS confronts new hurdles in integrating into wireless networks efficiently due to its passive nature. Consequently, the channel estimation for, both full and nearly passive RIS and the RIS deployments are compared under various wireless communication models and for single and multi-users. Lastly, the challenges and potential future study areas for the RIS aided wireless communication systems are proposed

Cooperative Radio Communications for Green Smart Environments

The demand for mobile connectivity is continuously increasing, and by 2020 Mobile and Wireless Communications will serve not only very dense populations of mobile phones and nomadic computers, but also the expected multiplicity of devices and sensors located in machines, vehicles, health systems and city infrastructures. Future Mobile Networks are then faced with many new scenarios and use cases, which will load the networks with different data traffic patterns, in new or shared spectrum bands, creating new specific requirements. This book addresses both the techniques to model, analyse and optimise the radio links and transmission systems in such scenarios, together with the most advanced radio access, resource management and mobile networking technologies. This text summarises the work performed by more than 500 researchers from more than 120 institutions in Europe, America and Asia, from both academia and industries, within the framework of the COST IC1004 Action on "Cooperative Radio Communications for Green and Smart Environments". The book will have appeal to graduates and researchers in the Radio Communications area, and also to engineers working in the Wireless industry. Topics discussed in this book include: • Radio waves propagation phenomena in diverse urban, indoor, vehicular and body environments• Measurements, characterization, and modelling of radio channels beyond 4G networks• Key issues in Vehicle (V2X) communication• Wireless Body Area Networks, including specific Radio Channel Models for WBANs• Energy efficiency and resource management enhancements in Radio Access Networks• Definitions and models for the virtualised and cloud RAN architectures• Advances on feasible indoor localization and tracking techniques• Recent findings and innovations in antenna systems for communications• Physical Layer Network Coding for next generation wireless systems• Methods and techniques for MIMO Over the Air (OTA) testin

SPATIAL SENSOR DATA PROCESSING AND ANALYSIS FOR MOBILE MEDIA APPLICATIONS

Ph.DDOCTOR OF PHILOSOPH

Exploiting intrinsic flash properties to enhance modern storage systems

The longstanding goals of storage system design have been to provide simple abstractions for applications to efficiently access data while ensuring the data durability and security on a hardware device. The traditional storage system, which was designed for slow hard disk drive with little parallelism, does not fit for the new storage technologies such as the faster flash memory with high internal parallelism. The gap between the storage system software and flash device causes both resource inefficiency and sub-optimal performance. This dissertation focuses on the rethinking of the storage system design for flash memory with a holistic approach from the system level to the device level and revisits several critical aspects of the storage system design including the storage performance, performance isolation, energy-efficiency, and data security. The traditional storage system lacks full performance isolation between applications sharing the device because it does not make the software aware of the underlying flash properties and constraints. This dissertation proposes FlashBlox, a storage virtualization system that utilizes flash parallelism to provide hardware isolation between applications by assigning them on dedicated chips. FlashBlox reduces the tail latency of storage operations dramatically compared with the existing software-based isolation techniques while achieving uniform lifetime for the flash device. As the underlying flash device latency is reduced significantly compared to the conventional hard disk drive, the storage software overhead has become the major bottleneck. This dissertation presents FlashMap, a holistic flash-based storage stack that combines memory, storage and device-level indirections into a unified layer. By combining these layers, FlashMap reduces critical-path latency for accessing data in the flash device and improves DRAM caching efficiency significantly for flash management. The traditional storage software incurs energy-intensive storage operations due to the need for maintaining data durability and security for personal data, which has become a significant challenge for resource-constrained devices such as mobiles and wearables. This dissertation proposes WearDrive, a fast and energy-efficient storage system for wearables. WearDrive treats the battery-backed DRAM as non-volatile memory to store personal data and trades the connected phone’s battery for the wearable’s by performing large and energy-intensive tasks on the phone while performing small and energy-efficient tasks locally using battery-backed DRAM. WearDrive improves wearable’s battery life significantly with negligible impact to the phone’s battery life. The storage software which has been developed for decades is still vulnerable to malware attacks. For example, the encryption ransomware which is a malicious software that stealthily encrypts user files and demands a ransom to provide access to these files. Prior solutions such as ransomware detection and data backups have been proposed to defend against encryption ransomware. Unfortunately, by the time the ransomware is detected, some files already undergo encryption and the user is still required to pay a ransom to access those files. Furthermore, ransomware variants can obtain kernel privilege to terminate or destroy these software-based defense systems. This dissertation presents FlashGuard, a ransomware-tolerant SSD which has a firmware-level recovery system that allows effective data recovery from encryption ransomware. FlashGuard leverages the intrinsic flash properties to defend against the encryption ransomware and adds minimal overhead to regular storage operations.Ph.D

NASA/ASEE Summer Faculty Fellowship Program

This document is a collection of technical reports on research conducted by the participants in the 1993 NASA/ASEE Summer Faculty Fellowship Program at KSC. The basic common objectives of the Program are: to further the professional knowledge of qualified engineering and science faculty members; to stimulate an exchange of ideas between participants and NASA; to enrich and refresh the research and teaching activities of participants' institutions; and to contribute to the research objectives of the NASA centers. 1993 topics include wide band fiber optic communications, a prototype expert/information system for examining environmental risks of KSC activities, alternatives to premise wiring using ATM and microcellular technologies, rack insertion end effector (RIEE) automation, FTIR quantification of industrial hydraulic fluids in perchloroethylene, switch configuration for migration to optical fiber network, and more