Reactive Context-Aware Programming

Using state of the art tools, context-aware applications are notified of relevant changes in their environment through event handlers which are triggered by dedicated middleware. The events signalled by the middleware should percolate through the entire application, requiring a carefully crafted network of observers combined with complex synchronization code to address the inherent concurrency issues. This paper proposes the adoption of reactive programming techniques to bridge the gap between the event-driven middleware and the application

Quality-Aware Reactive Programming for the Internet of Things

© 2017, IFIP International Federation for Information Processing. The reactive paradigm recently became very popular in user-interface development: updates — such as the ones from the mouse, keyboard, or from the network — can trigger a chain of computations organised in a dependency graph, letting the underlying engine control the scheduling of these computations. In the context of the Internet of Things (IoT), typical applications deploy components in distributed nodes and link their interfaces, employing a publish-subscribe architecture. The paradigm for Distributed Reactive Programming marries these two concepts, treating each distributed component as a reactive computation. However, existing approaches either require expensive synchronisation mechanisms or they do not support pipelining, i.e., allowing multiple “waves” of updates to be executed in parallel. We propose Quarp (Quality-Aware Reactive Programming), a scalable and light-weight mechanism aimed at the IoT to orchestrate components triggered by updates of data-producing components or of aggregating components. This mechanism appends meta-information to messages between components capturing the context of the data, used to dynamically monitor and guarantee useful properties of the dynamic applications. These include the so-called glitch freedom, time synchronisation, and geographical proximity. We formalise Quarp using a simple operational semantics, provide concrete examples of useful instances of contexts, and situate our approach in the realm of distributed reactive programming.FCT - Fuel Cell Technologies Program(732505 LightKone)Partially financed by the personal FCT grant SFRH/BPD/91908/2012. The research leading to these results has received funding from the European Union’s Horizon 2020 - The EU Framework Programme for Research and Innovation 2014-2020, under grant agreement No. 732505.Project “TEC4Growth - Pervasive Intelligence, Enhancers and Proofs of Concept with Industrial Impact/NORTE-01- 0145-FEDER-000020” is financed by the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, and through the European Regional Development Fund (ERDF).info:eu-repo/semantics/publishedVersio

AtomsMasher: Personal Reactive Automation for the Web

The rise of "Web 2.0" has seen an explosion of web sites for the social sharing of personal information. To enable users to make valuable use of the rich yet fragmented sea of public, social, and personal information, data mashups emerged to provide a means for combining and filtering such information into coherent feeds and visualizations. In this paper we present AtomsMasher (AM), a new framework which extends data mashups into the realm of context-aware reactive behaviors. Reactive scripts in AM can be made to trigger automatically in response to changes in its world model derived from multiple web-based data feeds. By exposing a simple state-model abstraction and query language abstractions of data derived from heterogeneous web feeds through a simulation-based interactive script debugging environment, AM greatly simplifies the process of creating such automation in a way that is flexible, predictable, scalable and within the reach of everyday Web programmers

The Environment as an Argument

Context-awareness as defined in the setting of Ubiquitous Computing [3] is all about expressing the dependency of a specific computation upon some implicit piece of information. The manipulation and expression of such dependencies may thus be neatly encapsulated in a language where computations are first-class values. Perhaps surprisingly however, context-aware programming has not been explored in a functional setting, where first-class computations and higher-order functions are commonplace. In this paper we present an embedded domain-specific language (EDSL) for constructing context-aware applications in the functional programming language Haskell. © 2012 Springer-Verlag

Event-driven Adaptation in COP

Context-Oriented Programming languages provide us with primitive constructs to adapt program behaviour depending on the evolution of their operational environment, namely the context. In previous work we proposed ML_CoDa, a context-oriented language with two-components: a declarative constituent for programming the context and a functional one for computing. This paper describes an extension of ML_CoDa to deal with adaptation to unpredictable context changes notified by asynchronous events.Comment: In Proceedings PLACES 2016, arXiv:1606.0540

Mixing the reactive with the personal: Opportunities for end-user programming in personal information management

The transition of personal information management (PIM) tools off the desktop to the Web presents an opportunity to augment these tools with capabilities provided by the wealth of real-time information readily available. In this chapter, we describe a personal information assistance engine that lets end-users delegate to it various simple context- and activity-reactive tasks and reminders. Our system, Atomate, treats RSS/ATOM feeds from social networking and life-tracking sites as sensor streams, integrating information from such feeds into a simple unified RDF world model representing people, places and things and their time-varying states and activities. Combined with other information sources on the web, including the user's online calendar, web-based e-mail client, news feeds and messaging services, Atomate can be made to automatically carry out a variety of simple tasks for the user, ranging from context-aware filtering and messaging, to sharing and social coordination actions. Atomate's open architecture and world model easily accommodate new information sources and actions via the addition of feeds and web services. To make routine use of the system easy for non-programmers, Atomate provides a constrained-input natural language interface (CNLI) for behavior specification, and a direct-manipulation interface for inspecting and updating its world model