Our understanding of the world comes from our engaged interaction with it. Through embodied interaction we reveal our knowledge and skill; our knowing-in-action. This skill is tacit and typically non-vocalisable. This perspective of Embodied Interaction has long influenced HCI. Through reflection, however, we surface and interrogate this knowledge, changing our actions on-the-go. This reflection is intuitive and dynamic. This reflection is embodied. The existing literature on reflection in HCI has tended to consider a reflection that is separated from the action, emphasising a thoughtful and conceptual consideration. This thesis breaks from this tradition through its embodied perspective; considering purposeful reflection-on-action (after the activity) in physical tasks. Through a consideration of physical tasks, comes an emphasis on tacit knowledge. Yet reflection-on-action does not benefit from any of the tacit richness of the activity under consideration. This body of work explores tools and techniques to bring embodied and tacit knowledge to reflection-on-action, facilitating richer reflective practices. In combination with the already embodied reflection-in-action (during the activity), this thesis explores Designing for Embodied Reflection. Through an aim to support and enhance existing reflective practices, this thesis examines: the specifics of reflection in-the-world; technologies as a tool to assist reflective practice; the tensions of streamlining these tools into existing practice; and the facilitated novel opportunities for reflection. This thesis contributes a novel embodied perspective on reflection to HCI, highlighting the link between reflection and embodied interaction in the social science literature, providing a novel definition and feature set of reflection and using these to conduct an exploration of reflection in-the-wild, in domains emphasising different scales of physicality and reflective· rhythms. These works highlight: the burden of reflection; planning-for-reflection; the materiality of reflection; the opportunities in reflective coaching; the ambiguities of reflection-in-action and reflection-on-action; the interplay of social and individual reflection in real-world settings; and the complex relationship between the features of reflection. From this, a series of design considerations for embodied reflection and an updated definition of reflection are presented.

Smart Card devices are commonly used on many secure applications where there is a need to identify the card holder in order to provide a personalised service. The value of access to locked data and services makes Smart Cards a desirable attack target for hackers of all sorts. The range of attacks a Smart Card and its environment can be subjected to ranges from social engineering to exploiting hardware and software bugs and features. This research has focused on several hardware related attacks and potential threats. Namely, power glitch attack, power analysis, laser attack, the potential effect on security of memory power consumption reduction techniques and using a re-configurable instruction set as method to harden opcode interpretation. A semi-automated simulation environment to test designs against glitch attacks and power analysis has been developed. This simulation environment can be easily integrated within Atmel’s design flow to bring assurance of their designs’ behaviour and permeability to such attacks at an early development stage. Previous power analysis simulation work focused on testing the implementation of part of the cryptographic algorithm. This work focuses on targeting the whole algorithm, allowing the test of a wider range of countermeasures. A common glitch detection approach is monitoring the power supply for abnormal voltage values and fluctuations. This approach can fail to detect some fast glitches. The alternative approach used in this research monitors the effects of a glitch on a mono-stable circuit sensitive to fault injection by glitch attacks. This work has resulted in a patented glitch detector that improves the overall glitch detection range. The use of radiation countermeasures as laser countermeasures and potential sensors has been investigated too. Radiation and laser attacks have similar effects on silicon devices. Whilst several countermeasures against radiation have been developed over the years, almost no explicit mention of laser countermeasures was found. This research has demonstrated the suitability of using some radiation countermeasures as laser countermeasures. Memory partitioning is a static and dynamic power consumption reduction technique successfully used in various devices. The nature of Smart Card devices restricts the applicability of some aspects of this power reduction technique. This research line has resulted in the proposal of a memory partitioning approach suitable to Smart Cards.

The purpose of this research work is to propose an improved method for real-time sensitivity analysis (SA) applicable to large-scale complex systems. Borrowed from the EventTracker principle of the interrelation of causal events, it deploys the Rank Order Clustering (ROC) method to automatically group every relevant system input to parameters that represent the system state (i.e. output). The fundamental principle of event modelling is that the state of a given system is a function of every acquirable piece of knowledge or data (input) of events that occur within the system and its wider operational environment unless proven otherwise. It therefore strives to build the theoretical and practical foundation for the engineering of input data. The event modelling platform proposed attempts to filter unwanted data, and more importantly, include information that was thought to be irrelevant at the outset of the design process. The underpinning logic of the proposed Event Clustering technique (EventiC) is to build causal relationship between the events that trigger the inputs and outputs of the system. EventiC groups inputs with relevant corresponding outputs and measures the impact of each input variable on the output variables in short spans of time (relative real-time). It is believed that this grouping of relevant input-output event data by order of its importance in real-time is the key contribution to knowledge in this subject area. Our motivation is that components of current complex and organised systems are capable of generating and sharing information within their network of interrelated devices and systems. In addition to being an intelligent recorder of events, EventiC could also be a platform for preliminary data and knowledge construction. This improvement in the quality, and at times the quantity of input data, may lead to improved higher level mathematical formalism. It is hoped that better models will translate into superior controls and decision making. It is therefore believed that the projected outcome of this research work can be used to predict, stabilize (control), and optimize (operational research) the work of complex systems in the shortest possible time. For proof of concept, EventiC was designed using the MATLAB package and implemented using real-time data from the monitoring and control system of a typical cement manufacturing plant. The purpose for this deployment was to test and validate the concept, and to demonstrate whether the clusters of input data and their levels of importance against system performance indicators could be approved by industry experts. EventiC was used as an input variable selection tool for improving the existing fuzzy controller of the plant. Finally, EventiC was compared with its predecessor EventTracker using the same case study. The results revealed improvements in both computational efficiency and the quality of input variable selection.

The verification of real-time systems has gained much interest in the formal verification community during the past two decades. In this thesis, we investigate two real-time verification problems that benefit from the techniques normally used in untimed verification. The first part of this thesis is concerned with the monitoring of real-time specifications. We study the expressiveness of metric temporal logics over timed words, a problem that dates back to early 1990s. We show that the logic obtained by extending Metric Temporal Logic (MTL) with two families of new modalities is expressively complete for the Monadic First-Order Logic of Order and Metric (FO[<,+1]) in time-bounded settings. Furthermore, by allowing rational constants, expressive completeness also holds in the general (time-unbounded) setting. Finally, we incorporate several notions and techniques from LTL monitoring to obtain the first trace-length independent monitoring procedure for this logic. The second part of this thesis concerns a decision problem regarding UAVs: given a set of targets (each ascribed with a relative deadline) and flight times between each pair of targets, is there a way to coordinate a flock of k identical UAVs so that all targets are visited infinitely often and no target is ever left unvisited for a time longer than its relative deadline? We show that the problem is PSPACE-complete even in the single-UAV case, thereby corrects an erroneous claim from the literature. We then complement this result by proposing an efficient antichain-based approach where a delayed simulation is used to prune the state space. Experimental results clearly demonstrate the effectiveness of our approach.