Background Most adults do not engage in sufficient physical activity to maintain good health. Smartphone apps are increasingly used to support physical activity but typically focus on tracking behaviors with no support for the complex process of behavior change. Tracking features do not engage all users, and apps could better reach their targets by engaging users in reflecting their reasons, capabilities, and opportunities to change. Motivational interviewing supports this active engagement in self-reflection and self-regulation by fostering psychological needs proposed by the self-determination theory (ie, autonomy, competence, and relatedness). However, it is unknown whether digitalized motivational interviewing in a smartphone app engages users in this process. Objective This study aimed to describe the theory- and evidence-based development of the Precious app and to examine how digitalized motivational interviewing using a smartphone app engages users in the behavior change process. Specifically, we aimed to determine if use of the Precious app elicits change talk in participants and how they perceive autonomy support in the app. Methods A multidisciplinary team built the Precious app to support engagement in the behavior change process. The Precious app targets reflective processes with motivational interviewing and spontaneous processes with gamified tools, and builds on the principles of self-determination theory and control theory by using 7 relational techniques and 12 behavior change techniques. The feasibility of the app was tested among 12 adults, who were asked to interact with the prototype and think aloud. Semistructured interviews allowed participants to extend their statements. Participants’ interactions with the app were video recorded, transcribed, and analyzed with deductive thematic analysis to identify the theoretical themes related to autonomy support and change talk. Results Participants valued the autonomy supportive features in the Precious app (eg, freedom to pursue personally relevant goals and receive tailored feedback). We identified the following five themes based on the theory-based theme autonomy support: valuing the chance to choose, concern about lack of autonomy, expecting controlling features, autonomous goals, and autonomy supportive feedback. The motivational interviewing features actively engaged participants in reflecting their outcome goals and reasons for activity, producing several types of change talk and very little sustain talk. The types of change talk identified were desire, need, reasons, ability, commitment, and taking steps toward change. Conclusions The Precious app takes a unique approach to engage users in the behavior change process by targeting both reflective and spontaneous processes. It allows motivational interviewing in a mobile form, supports psychological needs with relational techniques, and targets intrinsic motivation with gamified elements. The motivational interviewing approach shows promise, but the impact of its interactive features and tailored feedback needs to be studied over time. The Precious app is undergoing testing in a series of n-of-1 randomized controlled trials.

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The Internet of Things is evolving around a plethora of vertical platforms, each specifically suited to a given scenario and often adopting proprietary communications, device and resource control protocols. The emerging need for crossdomain IoT applications and services highlights the necessity of interoperability across IoT platforms for a unified and secure sharing of and access to sensing/actuating resources. This position paper describes the current state of the IoT landscape, the opportunities that appear towards its sustainable evolution as well as the challenges that need to be addressed. In this context, the vision and objectives of the H2020 symbIoTe project are also presented; symbIoTe aims at the interoperability of IoT platforms by offering a flexible interoperability framework that will allow i) vertical IoT platforms to cooperate, ii) collaborative IoT platforms to form IoT-platform federations for exchange of resources and iii) independent developers to create innovative and cross-domain applications.

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While with traditional QoS-based charging the pricing structure mainly reflects the delivered QoS in order to regulate the demand, the role of service prices in a Quality of Experience (QoE) context is more complex. Amongst others, the charged price may in addition have a direct impact on the user's quality perception. In this paper, we analyze the structure of the resulting fixpoint problem and discuss the corresponding equilibrium. Based on recent user trials, additional insight into the characteristics of the related feedback loops is provided, before we conclude with outlining some consequences for future QoE-based charging mechanisms.

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In contrast to traditional QoS-based charging, charges for QoE (Quality of Experience) play a double role both as part of the evaluation context and as counterpart of the user's willingness-to-pay for service quality. To further investigate this link between pricing and QoE, we combine some unexpected results from empirical quality perception experiments with the socio-psychological theory of cognitive dissonance. With this approach, we are able to explain the influence of active user decisions on QoE. Moreover, economical implications, further research opportunities and practical advices for quality testing are presented.

Within the current paradigm change from Quality-of-Service (QoS) towards Quality-of-Experience (QoE), the question of how to charge for QoE is widely neglected in the research community despite of its obvious importance. In this paper, we present and analyze a fixed point model which specifically reflects the double role of prices, i.e. as regulating factor for demand size and at the same time as part of the QoE-based user context. The model is validated through comprehensive user trial results which allow interesting insights into the temporal behavior of end users who are confronted with a fine-grained scale of choices on video quality and corresponding tariffs.