Yann Gripay

A simple (yet powerful) algebra for pervasive environments

Querying non-conventional data is recognized as a major issue in new environments and applications such as those occurring in pervasive computing. A key issue is the ability to query data, streams and services in a declarative way. Our overall objective is to make the development of pervasive applications easier through database principles. In this paper, through the notion of virtual attributes and binding patterns, we define a data-centric view of pervasive environments: the classical notion of database is extended to come up with a broader notion, defined as relational pervasive environment, integrating data, streams and active/passive services. Then, the so-called Serena algebra is proposed with operators to homogeneously handle data and services. Moreover, the notion of stream can also be smoothly integrated into this algebra. A prototype of Pervasive Environment Management System has been implemented on which first experiments have been conducted to validate our approach.

UbiWare: web-based dynamic data & service management platform for AmI

The surrounding space is constantly augmented by a myriad of devices that expose heterogeneous data, like slower-changing data, dynamic data streams and functionalities. Developing applications that cope with heterogeneous data and diverse communication protocols is a tedious task. The success of such applications depends on the performance of data access and on the easy management of available data. To address these challenges, we propose UbiWare, a middleware that facilitates application development for ambient intelligence. We abstract the surrounding space as a database-like environment and the heterogeneous entities and devices as data services that produce data. To query the distributed data services and access their data, we introduce an API that greatly simplifies application development and is compatible with the different operators used by query engines in Data Stream Management Systems or Pervasive Environment Management Systems.

ColisTrack: testbed for a pervasive environment management system

One of the leading challenges for pervasive computing is to ease the application development to smoothly handle the surrounding environment. We consider the case where the environment produces heterogeneous and continuous data, e. g. temperature readings, car positions... We have defined a scenario for containers transportation tracking in a medical context involving the transportation of fragile biological matter in sensor-enhanced containers. This scenario has been simulated as a testbed and offers a very nice setting to measure the agility of data-centric application development. On top of this scenario, we have built a pervasive application using a Pervasive Environment Management System called SoCQ (Service oriented Continuous Queries). SoCQ provides a data-oriented perspective of the pervasive environment, mixing classical data, streams and functionalities. For the demo, our objective is twofold: first, from the application developer point of view, she has access to the underlying SoCQ-schema and she may pose her own SQL-like queries to the simulated environment. Second, from the end-user point of view, she may quite easily interact with the environment either through a general dynamic visualization with Google Maps of hospitals, cars moving along roads and medical containers waiting or being transported, or by getting SMS notifications on her own phone of results of predefined queries.

Context-Sensitive Security Framework for Pervasive Environments

Pervasive systems enable us to have an overview of what digital environments will look like in the future. Opportunities given by pervasive systems, both in terms of applications and services to the user are manifold and very promising. From the user point of view, privacy and security of her personal data is a real issue, which must be addressed to make pervasive systems accepted. A wide adoption of pervasive systems can not be possible without an integrated approach to security. We propose a model of security and privacy for pervasive environments, integrated with an architecture, namely PerSE, in which privacy is a main concern and is at the core of the conception

SoCQ: A Framework for Pervasive Environments

Querying non-conventional data sources is recognized as a major issue in new environments and applications such as those occurring in pervasive computing. A key issue is the ability to query data, streams and services in a declarative way. In this paper, we propose a framework that defines a data-centric view of pervasive environments: the classical notion of database is extended to come up with a broader notion, defined as relational pervasive environment, homogeneously integrating data, streams and active/passive services. It allows declarative definitions of service-oriented continuous queries using a SQL-like language, based on the so-called Serena algebra. We also tackle the design of a Pervasive Environment Management System that handles non-conventional data sources and service-oriented continuous queries.

Energy Enhancement of Multi-application Monitoring Systems for Smart Buildings

High energy consumption of sensor devices is a major problem in smart building systems, since it strongly impacts the system lifetime. However, existing approaches are often fitted to a single monitoring application and rely on static configurations for sensor devices: optimization of their acquisition and transmission frequencies to actual multiple application requirements is not tackled. In this paper, we focus on energy-aware dynamic sensor device re-configuration to lower energy consumption while fulfilling real-time application requirements. We introduce the Smart-Service Stream-oriented Sensor Management (3SoSM) that binds together sensor configuration and management of sensor data streams. We present a multi-application monitoring system architecture that optimizes application requirements for data streams into sensor device configurations, and we relate the experiments with our experimental platform.

Management of data sources and services in pervasive environments

Our daily environment contains more and more computerized devices, and tends to become a pervasive environment. Pervasive applications allow the end user to use a large number of heterogeneous devices, potentially invisible to him/her. To manage such kinds of applications, a distributed and modular architecture is required to handle the devices heterogeneity and their dynamicity, concerning their availability as well as the nature of data and services they can provide. In this article, we propose an architecture integrated in our SoCQ project [16] that builds an abstraction of the environment and thus simplifies the development of pervasive applications based on this abstraction. We also detail the current implementation of our architecture that includes the use of the UPnP technology.

Extending conceptual data model for dynamic environment

The design of data-centric pervasive applications in dynamic environments is raising more and more interests in many application domains. To design pervasive applications, we take advantage of recent advances in database management systems dealing with streams and services: new systems exist that simplify pervasive application deployment. We believe that the field is now mature and that conceptual data models like Entity-Relationship models could be revisited at the light of the pervasive application requirements. In this paper, we propose to extend an Entity-Relationship model to a new conceptual model, the so-called XD-ER equipped with some key notions: dynamic datasource types to model both streams and services and dynamic relationship types to link dynamic datasource types to classical entity types. Based on the SoCQ data model, we point out how to transform a conceptual XD-ER schema into XD-Relations straightly implementable in the SoCQ engine. The use of our model is shown through a running example.

Managing Pervasive Environments through Database Principles: A Survey

As initially envisioned by Mark Weiser, pervasive environments are the trend for the future of information systems. Heterogeneous devices, from small sensors to framework computers, are all linked though ubiquitous networks ranging from local peer-to-peer wireless connections to the world-wide Internet. Managing such environments, so as to benefit from its full potential of available resources providing information and services, is a challenging issue that covers several research fields like data representation, network management, service discovery. . . However, some issues have already been tackled independently by the database community, e.g. for distributed databases or data integration. In this survey, we analyze current trends in pervasive environment management through database principles and sketch the main components of our ongoing project SoCQ, devoted to bridging the gap between pervasive environments and databases.

Towards service-oriented continuous queries in pervasive systems

Pervasive information systems give an overview of what digital environments should look like in the future. From a data-centric point of view, traditional databases have to be used alongside with non-conventional data sources like data streams, services and events. In this paper, we tackle the definition of continuous queries combining standard relations, data streams and services in a declarative language extending SQL. We first define virtual tables with binding patterns as a way to get a unified view of the pervasive environment. Relations, data streams and services can be homogeneously queried using a SQL-like language, on top of which query optimization can be performed. We also introduce a new clause defining the optimizing criteria to dynamically choose the best way to handle each event.