Björn A. Johnsson

An On-Demand WebRTC and IoT Device Tunneling Service for Hospitals

In this paper we present the implementation of a WebRTC gateway service that can forward ad-hoc RTP data plane traffic from a browser inside a local hospital network to a browser on a local home network. The gateway leverages the same infrastructure used by the hospital to tunnel sensor and control data for medical devices in home-care deployments. In our use case, doctors at hospitals can only access port 80 through the hospital firewall on external machines, and they need to communicate with patients who are typically behind a NAT in a local WiFi network. VPN solutions only work for staff but not between patients and staff. Our solution solves this problem by redirecting all WebRTC traffic through a gateway service on the local network that has a secure tunnel established with a public gateway. The public gateway redirects traffic from multiple concurrent streams securely between local gateway services that connect to it. The local gateways also communicate with browsers on their local network to mimic a direct browser-to-browser connection without having to change the browser runtime. We have demonstrated that this technique works well within the hospital network and arbitrary patient networks, without the need for any individual host configuration. In our evaluation we show that the latency overhead is 18-20 ms for each concurrent stream added to the same gateway service, which is not discernible with a naked eye until you have more than 10 concurrent streams.

Supporting collaborative healthcare using PalCom — The itACiH system

Healthcare is increasingly a collaborative effort involving caregivers from several different organizations providing services to the same patient. This is particularly the case in care for the elderly and chronically ill, where a preference for care in the home is common. Current systems lack support for care scenarios that require mobility and intra-organizational collaboration. This results in an inefficient work situation that relies on old technologies - paper notes, phones calls, fax - for communication, which ultimately threaten the medical safety of patients. In this paper we present a system designed for this collaborative situation covering both mobile work in a single organization (home care) and collaboration across organizations, as well as connecting devices to people. Although developed as part of a research project, the use of participatory design and iterative development has resulted in early adoption of the system which is now in professional use by both the participating hospital and municipality.

Some like it hot: automating an electric kettle using PalCom

In this demo we will show how devices from different vendors, using different protocols, can be combined and made to work together without detailed low-level programming by the user. The small example we have chosen uses a radio-controlled power socket from one vendor and a temperature sensor from another vendor. We use these to create a remotely controlled electric kettle, which keeps the water at the point of boiling, ready to make tea at any time. We also show how we very easy can use a mobile phone for remote control and monitoring of the kettle. It is all built with a simple-to-use graphical user interface offered by the PalCom middleware, and will be modified as part of the demo.

Evaluating a GUI Development Tool for Internet of Things and Android

In the emerging field of Internet of Things (IoT), where computerized devices are combined in creative new ways, there is a need to create Graphical User Interfaces (GUIs) for the systems being built, e.g. in the form of Android “apps”. This is generally a complicated, time consuming task. We report from a controlled experiment that evaluates a new approach for building GUIs that aims to make it easier for more people to build quality GUIs. A tool supporting the new approach (GPE) was compared to Android Studio (AS\({}_{}\)), the industry standard for Android development. Our data analysis shows that GPE is more effective than AS\({}_{}\) when performing certain tasks, with no measurable degrade in the quality of the produced GUIs. We conclude that non-Android developers and Android developers alike should consider using GPE rather than AS\({}_{}\) when building Android GUIs for PalCom based IoT systems.

End-User Composition of Graphical User Interfaces for PalCom Systems

In ubiquitous computing, end-user composition allows users to combine multiple single-purpose devices into new, interesting constellations. In PalCom – a ubiquitous middleware – this is achieved without the need to write program code. In this paper we present a solution that in the same way allows users to create Graphical User Interfaces (GUIs) for such systems without coding. The approach is to focus on presenting functionality in a GUI rather than attaching functionality to manually added components. We see this as an inverted way of working with GUI development. The solution was realized in the form of a graphical editor for a PalCom specific User Interface Description Language. The tool produces platform independent GUI descriptions that can be interpreted on any platform. When compared to another common tool, the presented editor exhibited roughly 10x shorter development times. The learning time for new users was also evaluated with positive outcome, and a scalability evaluation showed that the solution can be used to create professional grade GUIs.

Evaluating a Dynamic Keep-Alive Messaging Strategy for Mobile Pervasive Systems

Abstract: Timely loss-of-contact detection between devices in pervasive systems using mobile networks is an important aspect for both functionality and user experience. Traditional schemes where time-to-live is defined by the service provider are not adequate in mobile networks where communication failures are frequent. On the other hand, schemes using keep-alive messaging tend to increase the communication overhead, in particular if the time to detect a loss of contact needs to be short. We introduce a strategy where the time between keep-alive messages is adjusted dynamically according to the need in a particular application. Our solution was evaluated with usage data from a professional application built on the PalCom framework. The measurements show a 96 % decrease of the communication overhead while still maintaining the same system responsiveness.