Christophe Jacquet

Bridging the Chasm between Executable Metamodeling and Models of Computation

The complete and executable definition of a Domain Specific Language (DSL) includes the specification of two essential facets: a model of the domain-specific concepts with actions and their semantics; and a scheduling model that orchestrates the actions of a domain-specific model. Metamodels can capture the former facet, while Models of Computation (MoCs) capture the latter facet. Unfortunately, theories and tools for metamodeling and MoCs have evolved independently, creating a cultural and technical chasm between the two communities. Consequently, there is currently no framework to explicitly model and compose both facets of a DSL. This paper introduces a new framework to combine a metamodel and a MoC in a modular fashion. This allows (i) the complete and executable definition of a DSL, (ii) the reuse of a given MoC for different domain-specific metamodels, and (iii) the use of different MoCs for a given metamodel, to account for variants of a DSL.

A Fault Detection and Diagnosis Framework for Ambient Intelligent Systems

Ambient intelligence (AmI) systems are smart interactive systems that perceive their surroundings using sensors and act upon them using actuators. One of the most common applications of such systems is Smart Homes. In this context, the ambient system can offer a great level of dependability if it is able to exploit available sensor data in order to autonomously perform diagnosis. However, ambient environments are dynamic in a sense that components, in general, and actuators and sensors, in particular, can be added or removed from the system at run-time. This dynamicity raises new challenges not addressed in the state of the art of fault detection and diagnosis techniques. Unlike classical control theory methods, control-loops between ambient system components cannot be pre-determined at design time. In this paper we propose a new approach based on the modeling of physical phenomena, allowing one to use available resources to predict the values that are supposed to be read by sensors. Comparing the predictions and the real readings allows us to detect potential faults. Fault detection may be followed by fault isolation, which tries to identify the faulty component precisely.

Semantic adaptation using CCSL clock constraints

When different parts of a system depend on different technical domains, the best suitable paradigm for modeling each part may differ. In this paper, we focus on the semantic adaptation between parts of a model which use different modeling paradigms in the context of model composition. We show how CCSL, a language for defining constraints and relations on clocks, can be used to define this semantic adaptation in a formal and modular way.

From Data to Events: Checking Properties on the Control of a System

We present a component-based description language for heterogeneous systems composed of several data flow processing components and a unique event- based controller. Descriptions are used both for generating and deploying implementation code and for checking safety properties on the systems. The only constraint is to specify the controller in a synchronous reactive language. We propose an analysis tool which transforms temporal logic properties of the system as a whole into properties on the events of the controller, and hence into synchronous reactive observers. If checks succeed, the final system is therefore correct by construction. When properties cannot be translated exactly into observers of the control, our tool is capable of generating approximate observers. In this case, the results are subject to interpretation, but can prove useful and help detect defects or even guarantee the correctness of a system.

An Architecture Description Language for Verification in Component-Based Software

In the context of component-based design, we propose ADLV, an architecture description language based on IDL3, which allows the specification of properties that should hold on the system. The joint description of both the structure of the application and the properties it should satisfy allows us to derive the properties that should be formally checked on the control component of the system. We focus here on the ADLV language and tool and on code generation for the CCM platform from ADLV descriptions. Code generation must preserve the semantics of special components that are in charge of interfacing the control and the processing parts of the application.

Dynamic cooperative information display in mobile environments

We introduce an interaction scenario in which users of public places can see relevant information items on public displays as they move. Public displays can dynamically collaborate and group with each other so as to minimize information clutter and redundancy. We analyse the usability constraints of this scenario in terms of information layout on the screens. This allows us to introduce a decentralized architecture in which information screens as well as users are modeled by software agents. We then present a simulator that implements this system.

Aides électroniques pour le déplacement des personnes non-voyantes: vue d'ensemble et perspectives

In this paper, we present an overview of current electronic locomotion aids for the blind and perspectives for future systems. We start with the two main issues raised by locomotion assistance for the blind : how to capture and present information. Then, we explain how these issues have been dealt with in existing devices, and we describe the techniques that have been used to solve them : infrared, ultrasonic and laser sensors to capture information; tactile and audio modalities to present information. After that, we expose some current ideas and results about a new generation of context-aware, semantics-enhanced locomotion assistance devices, that are expected to provide higher-level information than current ones do.

TESL: A language for reconciling heterogeneous execution traces

Various formalisms deal with time, and each of them has its own notion of time. When designing a system, it is often desirable to combine several of these formalisms to model different parts. Therefore one has to reconcile execution traces that may use different kinds of time (discrete, continuous, periodic) and different time scales (e.g. minutes, microseconds or even angles in degrees). In this article, we present a deterministic model of time which allows the specification of the coincidence of events that occur on different time scales, as well as instantaneous causality between events. This model supports both event-driven and time-driven specifications.

Multimodal Presentation of Information in a Mobile Context

This chapter deals with the design of multimodal information systems in the framework of ambient intelligence . Its agent architecture is based on KUP, an alternative to traditional software architecture models for human–computer interaction . The KUP model is accompanied by an algorithm for choosing and instantiating interaction modalities. The model and the algorithm have been implemented in a platform called PRIAM, with which we have performed experiments in pseudo-real scale.

A system for user task monitoring and assistance in ambient intelligent settings

Existing task models are generally static (not used at runtime) and are used for the design or predictive evaluation of interactive systems. We propose to use the task model at runtime, in order to monitor user actions, check that they have not made any mistakes and give help when needed. We present a task model suitable for ambient environments that dynamically assigns states to tasks at the runtime. We also describe a monitoring and assistance system that uses our dynamic task model. Finally, we present a validation of our system through a simulation that shows how the interactions with the task model at runtime results in a dynamic system capable of providing assistance to users while they are carrying out their daily tasks.