Time Reversed Electromagnetic Wave Propagation as a Novel Method of Wireless Power Transfer

We investigate the application of time-reversed electromagnetic wave propagation to transmit energy in a wireless power transmission system. “Time reversal” is a signal focusing method that exploits the time reversal invariance of the lossless wave equation to direct signals onto a single point inside a complex scattering environment. In this work, we explore the properties of time reversed microwave pulses in a low-loss ray-chaotic chamber. We measure the spatial profile of the collapsing wavefront around the target antenna, and demonstrate that time reversal can be used to transfer energy to a receiver in motion. We demonstrate how nonlinear elements can be controlled to selectively focus on one target out of a group. Finally, we discuss the design of a rectenna for use in a time reversal system. We explore the implication of these results, and how they may be applied in future technologies.

Augmented Dissent: The Affordances of ICTs for Citizen Protest (A Case Study of the Ukraine Euromaidan Protests of 2013-2014).

This dissertation research project uses the Euromaidan protests in Ukraine to inform and shape a theory of augmented dissent to help explain the complex ways in which protest participants guided by the political, social, and cultural contexts engage in dissent augmented by ICTs in a reality where both the physical and the digital are used in concert. The purpose of this research is to conceptualize the use and perception of ICTs in protest activity using the communicative affordances framework. Through a mixed-method research approach involving interviews with protest participants, as well as qualitative and thematic analysis of online content from social media pages of several key Euromaidan protest communities, the research project examines the role ICTs played in the information and media landscape during the Euromaidan protest. The findings of the online content analysis were used to inform the questions for the 59 semi-structured, open-ended interviews with Euromaidan protest participants in Ukraine and abroad. The research findings provide in-depth insights about how ICTs were used and perceived by protest participants, and their role as vehicles for information and civic media content. The study employs the theoretical framework of social media affordances to interpret the data gathered during the interviews and content analysis to better understand how digital media augmented citizens’ protest activity through affording them new possibilities for dissent, and how they made meaning of said protest activity as augmented by ICTs. The findings contribute towards shaping a theory of digitally augmented dissent that conceptualizes the complex relationship between citizens and ICTs during protest activity as an affordance-driven one, where online and offline tools and activity merge into a unified dissent space and extend or augment the possibilities for action in interesting, and sometimes unexpected ways. Such a conceptual model could inform broader theories about civic participation and digital activism in the post-Soviet world and beyond, as ICTs become an inseparable part of civic life.