The proposed system proved to be efficient by improving the user engagement and exercise performance outcomes. The results also suggest that the use of biomechanical standards to recognize movements is valuable in guiding users during rehabilitation exercises.

Over the last fifty years, research into street networks has gained prominence with a rapidly growing number of studies across disparate disciplines. These studies investigate a wide range of phenomena using a wealth of data and diverse analytical techniques. Starting within the fields of transport or infrastructure engineering, street networks have commonly been treated as sets of more or less homogeneous linear elements, connecting locations and intersecting at junctions. This view is commonly represented as a graph, which provides a common and rigorous formalisation accessible across disciplines and is particularly well-suited for problems such as flow optimisation and routing. Street networks are, however, complex objects of investigation and the way we model and then represent them as graphs has fundamental effects on the outcomes of a study. Many approaches to modelling street networks have been proposed, each lending itself to different analyses and supporting insights into diverse aspects of the urban system. Yet, this plurality and the relation between different models remains relatively obscure and unexplored. The motivations for adopting a given model of the network are also not always clear and often seem to follow disciplinary traditions. This paper provides an overview of key street network models and the prima facie merits of pertinent alternative approaches. It suggests greater attention to consistent use of terms and concepts, of graph representations and practical applications, and concludes with suggestions for possible ways forward.

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With the rise of sensors such as the Microsoft Kinect, Leap Motion, and hand motion sensors in phones (i.e., Samsung Galaxy S6), gesture-based interfaces have become practical. Unfortunately, today, to recognize such gestures, applications must have access to depth and video of the user, exposing sensitive data about the user and her environment. Besides these privacy concerns, there are also security threats in sensor-based applications, such as multiple applications registering the same gesture, leading to a conflict (akin to Clickjacking on the web). We address these security and privacy threats with Prepose, a novel domain-specific language (DSL) for easily building gesture recognizers, combined with a system architecture that protects privacy, security, and reliability with untrusted applications. We run Prepose code in a trusted core, and only return specific gesture events to applications. Prepose is specifically designed to enable precise and sound static analysis using SMT solvers, allowing the system to check security and reliability properties before running a gesture recognizer. We demonstrate that Prepose is expressive by creating a total of 28 gestures in three representative domains: physical therapy, tai-chi, and ballet. We further show that runtime gesture matching in Prepose is fast, creating no noticeable lag, as measured on traces from Microsoft Kinect runs. To show that gesture checking at the time of submission to a gesture store is fast, we developed a total of four Z3-based static analyses to test for basic gesture safety and internal validity, to make sure the socalled protected gestures are not overridden, and to check inter-gesture conflicts. Our static analysis scales well in practice: safety checking is under 0.5 seconds per gesture; average validity checking time is only 188 ms; lastly, for 97% of the cases, the conflict detection time is below 5 seconds, with only one query taking longer than 15 seconds.