Beyond representations: towards an action-centric perspective on tangible interaction

In the light of theoretical as well as concrete technical development, we discuss a conceptual shift from an information-centric to an action-centric perspective on tangible interactive technology. We explicitly emphasise the qualities of shareable use, and the importance of designing tangibles that allow for meaningful manipulation and control of the digital material. This involves a broadened focus from studying properties of the interface, to instead aim for qualities of the activity of using a system, a general tendency towards designing for social and sharable use settings and an increased openness towards multiple and subjective interpretations. An effect of this is that tangibles are not designed as representations of data, but as resources for action. We discuss four ways that tangible artefacts work as resources for action: (1) for physical manipulation; (2) for referential, social and contextually oriented action; (3) for perception and sensory experience; (4) for digitally mediated action

Setting the stage – embodied and spatial dimensions in emerging programming practices.

In the design of interactive systems, developers sometimes need to engage in various ways of physical performance in order to communicate ideas and to test out properties of the system to be realised. External resources such as sketches, as well as bodily action, often play important parts in such processes, and several methods and tools that explicitly address such aspects of interaction design have recently been developed. This combined with the growing range of pervasive, ubiquitous, and tangible technologies add up to a complex web of physicality within the practice of designing interactive systems. We illustrate this dimension of systems development through three cases which in different ways address the design of systems where embodied performance is important. The first case shows how building a physical sport simulator emphasises a shift in activity between programming and debugging. The second case shows a build-once run-once scenario, where the fine-tuning and control of the run-time activity gets turned into an act of in situ performance by the programmers. The third example illustrates the explorative and experiential nature of programming and debugging systems for specialised and autonomous interaction devices. This multitude in approaches in existing programming settings reveals an expanded perspective of what practices of interaction design consist of, emphasising the interlinking between design, programming, and performance with the system that is being developed

Socioeconomic status and out-of-hospital cardiac arrest

Background: Out-of-hospital cardiac arrest (OHCA) is a common cause of death. Around 6000 people in Sweden suffer OHCA each year and only about 10% survive. Historically, the focus of OHCA research has been on different treatments such as improved cardiopulmonary resuscitation (CPR) and early defibrillation. Less is known about how underlying risk factors such as socioeconomic status (SES) affect both the incidence and the chance of surviving an OHCA. Methods: The primary data source for this thesis was the Swedish Register of Cardiopulmonary Resuscitation (SRCR). Study I and Study II included consecutive cases of EMS-treated OHCAs in the Stockholm Region between the years 2006–2015 (Study I) and 2006–2017 (Study II). For these two studies the OHCAs were geocoded and linked to area-level SES data from Statistics Sweden. In Study III and Study IV SRCR OHCA data from the whole of Sweden for the years 2010–2017 were used. Data were linked to individual-level socioeconomic variables such as disposable household income and educational level from Statistics Sweden, comorbidity data from the National Patient Register and medication data from the Swedish Prescribed Drug Register. Specific aims and results: The aim of Study I was to investigate if socioeconomic characteristics in the area of residence affect the chance of survival after out-of-hospital cardiac arrest. A total of 7431 OHCAs were included in the study. The results suggested a significant association between a higher proportion of university-educated people and 30-day survival. Compared with patients in the lowest educational quintile, the highest quintile showed an adjusted odds ratio (OR) of 1.70 (95% CI=1.15 to 2.51). No significant relationship was seen for area-level income when adjusted for education. The aim of Study II was to investigate the association between area-level SES and the incidence of OHCA, and to investigate if this relationship is dependent on age. A total of 10 574 OHCAs in the Stockholm Region were included in the study. The OHCAs were distributed over 1349 areas which represented the main unit of analysis. Areas characterized by high SES showed an incidence rate ratio (IRR) of 0.56 (95% CI=0.45–0.70) among persons in the age group 0–44. The corresponding number for persons in the 45–64 age group was 0.53 (95% CI=0.45–0.62) and it was 0.59 (0.49–0.0) among persons in the 65–74 age group. In the two oldest age groups (75–84 and 85+) there was no significant association between area-level SES and the incidence of OHCA. The aim of Study III was to examine how individual-level disposable income and educational level is related to 30-day survival following an OHCA. A total of 31 489 OHCAs were included in the study. In the main model, disposable income level followed a gradientlike increase in chance of survival, with the highest estimate in the highest income quintile (OR = 1.89, 95% CI = 1.64–2.17). This relationship remained after adjusting for comorbidity resuscitation factors and initial rhythm. As regards educational level, the highest OR for 30- day survival was found among persons with four or more years of post-secondary education (OR 1.62, 95% CI=1.36–1.92). The aim of Study IV was to investigate the relationship between disposable income and the chance of having a shockable initial rhythm. A total of 18 099 witnessed OHCAs were included in the study. In the low-income tercile, the proportion with shockable rhythm was 30.2%, compared with 51.4% in the high-income tercile when the EMS response time was less than five minutes. The corresponding numbers were 15.9% vs. 27.6% when the EMS response time was more than 20 minutes. In adjusted logistic regression analyses (using restricted cubic splines) the relationship between income and the probability of shockable initial rhythm followed an S-shaped curve, with a small increase in the first income tercile, a steep increase in the second tercile, that levelled out in the third income tercile. This relationship was seen regardless of potential confounders, comorbidities, cardiac-arrest characteristics and previous medication. Conclusions: The current studies confirm associations between SES, incidence of OHCA, and survival following an OHCA. The results from Study I suggest that individuals living in areas with a higher proportion of university-educated people have a higher probability of surviving to 30 days following an OHCA. In Study II, areas characterized by low SES showed a higher incidence of OHCA. This relationship, however, was dependent on age, and the SESincidence relationship disappeared among people over 75 years of age. In Study III both individual-level income and education were associated with the probability of 30-day survival after OHCA. In Study IV, income was associated with the probability of having a shockable initial rhythm. Initial rhythm may work as a mediator in the relationship between socioeconomic status and survival after OHCA

Transmitting qubits through relativistic fields

Wireless communication derives its power from the simultaneous emission of signals in multiple directions. However, in the context of quantum communication, this phenomenon must be reconciled carefully with the no-cloning principle. In this context, we here study how wireless communication of quantum information can be realized via relativistic fields. To this end, we extend existing frameworks to allow for a non-perturbative description of, e.g., quantum state transfer. We consider, in particular, the case of 1+1 spacetime dimensions, which already allows a number of interesting scenarios, pointing to, for example, new methods for tasks similar to quantum secret sharing.Comment: v2: published versio

The capacitance of the circular parallel plate capacitor obtained by solving the Love integral equation using an analytic expansion of the kernel

The capacitance of the circular parallel plate capacitor is calculated by expanding the solution to the Love integral equation into a Fourier cosine series. Previously, this kind of expansion has been carried out numerically, resulting in accuracy problems at small plate separations. We show that this bottleneck can be alleviated, by calculating all expansion integrals analytically in terms of the Sine and Cosine integrals. Hence, we can, in the approximation of the kernel, use considerably larger matrices, resulting in improved numerical accuracy for the capacitance. In order to improve the accuracy at the smallest separations, we develop a heuristic extrapolation scheme that takes into account the convergence properties of the algorithm. Our results are compared with other numerical results from the literature and with the Kirchhoff result. Error estimates are presented, from which we conclude that our results is a substantial improvement compared with earlier numerical results.Comment: 15 pages, 3 figure

Circuit Satisfiability and Constraint Satisfaction around Skolem Arithmetic

We study interactions between Skolem Arithmetic and certain classes of Circuit Satisfiability and Constraint Satisfaction Problems (CSPs). We revisit results of Glaßer et al. [1] in the context of CSPs and settle the major open question from that paper, finding a certain satisfiability problem on circuits—involving complement, intersection, union and multiplication—to be decidable. This we prove using the decidability of Skolem Arithmetic. Then we solve a second question left open in [1] by proving a tight upper bound for the similar circuit satisfiability problem involving just intersection, union and multiplication. We continue by studying first-order expansions of Skolem Arithmetic without constants, (N;×), as CSPs. We find already here a rich landscape of problems with non-trivial instances that are in P as well as those that are NP-complete