An Avatar Architecture for the Web of Things Mrissa, Michael; Medini, Lionel; Jamont, Jean-Paul ...
IEEE internet computing,
2015-Mar.-Apr., 2015-3-00, 20150301, 2015-03, Volume:
19, Issue:
2
Journal Article
Peer reviewed
The Web of Things extends the Internet of Things by leveraging Web-based languages and protocols to access and control each physical object. In this article, the authors summarize ongoing work ...promoting the concept of an avatar as a new virtual abstraction to extend physical objects on the Web. An avatar is an extensible and distributed runtime environment endowed with an autonomous behavior. Avatars rely on Web languages, protocols, and reason about semantic annotations to dynamically drive connected objects, exploit their capabilities, and expose user-understandable functionalities as Web services. Avatars are also able to collaborate together to achieve complex tasks.
•We propose an approach based on fuzzy logic for adaptation planning middleware.•Addressed problem: the explosion in the number of rules that increases execution time.•We separately calculate each ...QoS value of an ideal variant for a given context state.•We define a fuzzy similarity method to select the most similar variant to the ideal.•Experiments show our approach both reduces the number of rules and execution time.
Mobile applications require an adaptation phase to adapt to the user's and application context. Utility functions or rules are most often used to make the adaptation planning or decision, i.e. select the most adapted variant for each required service. Fuzzy controllers are used when it is difficult or even impossible to construct precise mathematical models. In the case of mobile applications, the large number of Quality of Service (QoS) and context parameters causes an exponential increase in the number of rules (aka. rule explosion problem), that increases the processing time of the adaptation planning. To reduce the processing time and simplify the fuzzy control system, we propose the concept of ideal QoS. Fuzzy values of ideal QoS parameters are calculated using several fuzzy control systems to fit the context state and user preferences. A fuzzy logic similarity metric based on fuzzy sets and fuzzy operators is proposed to select the service variant having the nearest QoS values to the ideal. Experiments show that our approach can significantly improve both the number of rules and the processing time when selecting the variant that well adapts to environment changes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
As the number of connected objects increases, there is a need to offer rich user experience and facilitate communication between physical objects with Web-based solutions. Our work relies on the ...notion of avatar to extend an object on the Web. We herein propose a model for the avatar to expose functionalities based on the capabilities objects offer. We motivate our work with a temperature regulation scenario and we evaluate the applicability of our proposal with an implementation.
Enabling and automating interoperability in the Semantic Web of Things involves complex semantic reasoning tools to process knowledge graphs. To improve performance and energy efficiency, such tools ...should be deployed as close as possible to the devices, ideally on any available edge node. However, edge nodes often lack sufficient resources, especially memory. We propose a method to distribute reasoning in this context. We then evaluate three algorithms to plan the distribution over a network of heterogeneous nodes. These algorithms take into account architectural constraints such as the position of sensors and actuators and the available resources on each node, while minimizing costly data exchanges on the network.
Web Reasoning Using Fact Tagging Terdjimi, Mehdi; Médini, Lionel; Mrissa, Michael
Companion Proceedings of the The Web Conference 2018,
04/2018
Conference Proceeding
Open access
Today's Web applications tend to reason about cyclic data (i.e. facts that re-occur periodically) on the client side. Although they can benefit from efficient incremental maintenance algorithms ...capable of handling frequent data updates, existing rule-based algorithms cause successive re-derivations of previously inferred information. In this paper, we propose an incremental maintenance approach for rule-based reasoning that prevents successive re-computations of fact derivations. We tag (i.e. annotate) facts to keep trace of their provenance and validity. We compare our solution with the DRed-based incremental reasoning algorithm and show that it significantly outperforms this algorithm for fact updates in re-occurring situations, to the cost of tagging facts at their first insertion. Our experiments show that this cost can be recovered within a small number of cycles of deletions and reinsertions of explicit facts. We discuss the utility and limitations of our approach on Web clients and provide implementation packages of this reasoner that can be directly integrated in Web applications, on both server and client sides.
An Avatar-Based Adaptation Workflow for the Web of Things Terdjimi, Mehdi; Medini, Lionel; Mrissa, Michael ...
2016 IEEE 25th International Conference on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE),
06/2016
Conference Proceeding
The Web of Things (WoT) extends the Internet of Things to provide users with high-level features, involving physical objects connected through Web technologies and standards. Avatar-based ...infrastructures is one of the most promising solution for the WoT. Avatars are component-based software agents that extend physical objects and are able to reason about contextual information. A major challenge of the WoT is to allow applications to adapt to their environment. In this paper, we propose an approach to process multi-purpose adaptation in an avatar-based WoT infrastructure. Our approach relies on a context meta-model that offers accurate granularity levels of information required for the different types of adaptation involved in WoT applications. We show how avatar components pre-process data from different sources, handle an operational context model, and respond to adaptation requests. We evaluate the performance of our approach and compare the effects of our adaptation process in different experimental conditions.
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