Improving intelligibility and control in Ubicomp

Users often become frustrated when they are unable to understand and control a ubicomp environment. Previous work has suggested that ubicomp systems should be intelligible to allow users to understand how the system works and controllable to let users intervene when the system makes a mistake. In my thesis, I focus on novel user interfaces and interaction techniques to support intelligibility and control. Author Keywords intelligibility; explanations; control; end-user configuration; ubicomp; feedback; feedforward

SenseBelt:a belt-worn sensor to support cross-device interaction

Mobile interaction is shifting from a single device to simultaneous interaction with ensembles of devices such as phones, tablets, or watches. Spatially-aware cross-device interaction between mobile devices typically requires a fixed tracking infrastructure, which lim- its mobility. In this paper, we present SenseBelt – a sensing belt that enhances existing mobile interactions and enables low-cost, ad hoc sensing of cross-device gestures and interactions. SenseBelt enables proxemic interactions between people and their personal devices. SenseBelt also supports cross-device interaction be- tween personal devices and stationary devices, such as public displays. We discuss the design and implementation of SenseBelt together with possible applications. With an initial evaluation, we provide insights into the benefits and drawbacks of a belt-worn mediating sensor to support cross-device interactions

Cross-surface:challenges and opportunities of spatial and proxemic interaction

In this workshop, we will review and discuss open issues, technical challenges and conceptual models for multi-device spatial or proxemic interaction. We aim to bring together researchers, students and practitioners working on technical infrastructures, studies and designs of spatial interfaces, or domain specific multi-device applications that use space as a unit of analysis. We focus specifically on analysing how such interfaces, tools and tracking technology can be deployed "in the wild". The workshop will facilitate knowledge exchange about the current state of spatial and proxemic interactive systems, identify application domains and enabling technologies for cross-surface interactions in the wild, and establish a research community to develop effective strategies for successful design of cross-device interactions

Cross-surface:challenges and opportunities of spatial and proxemic interaction

In this workshop, we will review and discuss open issues, technical challenges and conceptual models for multi-device spatial or proxemic interaction. We aim to bring together researchers, students and practitioners working on technical infrastructures, studies and designs of spatial interfaces, or domain specific multi-device applications that use space as a unit of analysis. We focus specifically on analysing how such interfaces, tools and tracking technology can be deployed "in the wild". The workshop will facilitate knowledge exchange about the current state of spatial and proxemic interactive systems, identify application domains and enabling technologies for cross-surface interactions in the wild, and establish a research community to develop effective strategies for successful design of cross-device interactions

Endosomal size and membrane leakiness influence proton sponge-based rupture of endosomal vesicles

In gene therapy, endosomal escape represents a major bottleneck since nanoparticles often remain entrapped inside endosomes and are trafficked toward the lysosomes for degradation. A detailed understanding of the endosomal barrier would be beneficial for developing rational strategies to improve transfection and endosomal escape. By visualizing individual endosomal escape events in live cells, we obtain insight into mechanistic factors that influence proton sponge-based endosomal escape. In a comparative study, we found that HeLa cells treated with JetPEI/pDNA polyplexes have a 3.5-fold increased endosomal escape frequency compared to ARPE-19 cells. We found that endosomal size has a major impact on the escape capacity. The smaller HeLa endosomes are more easily ruptured by the proton sponge effect than the larger ARPE-19 endosomes, a finding supported by a mathematical model based on the underlying physical principles. Still, it remains intriguing that even in the small HeLa endosomes, <10% of the polyplex-containing endosomes show endosomal escape. Further experiments revealed that the membrane of polyplex-containing endosomes becomes leaky to small compounds, preventing effective buildup of osmotic pressure, which in turn prevents endosomal rupture. Analysis of H1299 and A549 cells revealed that endosomal size determines endosomal escape efficiency when cells have comparable membrane leakiness. However, at high levels of membrane leakiness, buildup of osmotic pressure is no longer possible, regardless of endosomal size. Based on our findings that both endosomal size and membrane leakiness have a high impact on proton sponge-based endosomal rupture, we provide important clues toward further improvement of this escape strategy

Vapor nanobubble is the more reliable photothermal mechanism for inducing endosomal escape of siRNA without disturbing cell homeostasis

Strategies for controlled delivery of therapeutic siRNA into living cells are in high demand as endosomal escape remains the most prominent bottleneck at the intracellular level. Photothermal properties of gold nanoparticles (AuNP) can be used to overcome the endosomal membrane barrier upon laser irradiation by two mechanisms: endosomal rupture by mechanical energy from water vapor nanobubbles (VNBs), or permeabilization of the endosomal membrane by heat diffusion. Here we evaluated how both mechanisms influence cargo release, transfection efficiency, acute cytotoxicity and cell homeostasis. Using a siRNA/AuNP drug delivery system we found that the in vitro release of siRNA from the AuNP carrier occurs equally efficiently by VNB formation or heat generation. Heat-mediated endosomal escape happened more efficiently in cells that had more particles per endosome, resulting in variable siRNA-induced downregulation (20-50%). VNB-mediated endosomal escape did not dependent on the number of AuNP per endosome, yielding high downregulations (50-60%) independent of the cell type. Effects on cell homeostasis by whole transcriptome analysis, showed a quick recover after 24 h or 48 h for either of both photothermal mechanisms. We conclude that VNBs are more consistent to induce efficient endosomal escape and gene silencing independent of the cell type without long lasting effects on cell homeostasis