Ubiquitous Computing, Location-Awareness and Query ... - Horizons

Ubiquitous Computing. Context and Location-Awareness. Location-Based Services. Query Processing. Overview. Pyramidal Presentation ...
1MB taille 5 téléchargements 318 vues
Self-Introduction Who am I ?

Country Affiliation

Sokendai (1st-year PhD student)

Supervisor

Prof. Ichiro Satoh

Research

Ubiquitous Computing

Homepage

web.mac.com/christianhoareau

クリスチャン ワロー

Christian  Hoareau

Self-Introduction Who am I ?

クリスチャン ワロー

Christian   Hoareau Paris

Saint-Denis

2006

2005

2003 B.Sc. in CS

Tokyo

M.Sc. in CS Distributed Systems

System Engineer (IBM)

PhD student

Réunion なに?

• One of the four overseas départements of France • The outermost region of European Union • Volcanic island • Population : 800, 000+ • ....

Réunion Just a glance

Ubiquitous Computing, Location-Awareness and Query Processing Christian Hoareau

Overview

Pyramidal Presentation

Query Processing Location-Based Services Context and Location-Awareness Ubiquitous Computing

A little of Lexical Semantics What does it mean ?

ubiquitous ¦yoō bikwətəs¦ present, appearing, or found everywhere. -- Oxford English Dictionnary

The computation has become ubiquitous or .... • pervasive • ambient • sentient • everyware • ...

?

1960~1970s

1980~1990s

2000 ~

size

one computer for many people

one computer for everyone many computing devices for everyone

?

number 1960~1970s

1980~1990s

2000 ~

Ubiquitous computing

Information Processing Capabilities

• Embedded processors • smaller, cheaper and faster • lightweight • more energy efficient • Wireless communications • ad/hoc • low power • high bandwidth • Storage • bigger and faster • Sensors

Context-Awareness

Overview

Pyramidal Presentation

Query Processing Location-Based Services Context and Location-Awareness Ubiquitous Computing

Context Some Definitions

• Location and identity of nearby people and object [Schilit and Theimer, 1994] • Location, identity, environment and time [Ryan et al., 1994] • Any information that can be used to characterize the situation of entities [Dey et al., 1996]

• Context encompasses more than just the user’s location, because other things of interest are also mobile and changing. Context includes lighting, noise level, network connectivity, communication costs, communication bandwidth, and even the social situation; e.g., whether you are with your manager or with a coworker [Schilit, 1998]

Context-Aware Services • Context Value Chain [Hegering et al., 2003]

Overview

Pyramidal Presentation

Query Processing Location-Based Services Context and Location-Awareness Ubiquitous Computing

Location-Based Services (LBS) Overview Prominent applications of Ubiquitous Computing... • Location provides relevant information on users’ context • Numerous location tracking systems now widely available (GPS, RFID-tags, WiFi-based positioning, etc.) • Many application domains (e.g., maps & way finding, tracking, social mobile apps, location-specific content) ... but : • tend to be application-specific • usually rely on centralized, and inadequate, database systems

LBS Query Processing [Becker et al. , 2005] • simple position queries, e.g. ”where is the conference room ?” • nearest neighbor queries, e.g. ”where is the closest sushi restaurant ?” • naviguation queries, e.g. ”how to reach the bus terminal ?” • range queries, e.g. ”what are the conbinis located in my neighboorhood ?”

Goal : Provide a query framework for LBS, by exploring the connection between decentralized location model and query processing

Query Processing for LBS Why ?

Query Processing for LBS Why ?

indoor query processing

? Goal : Provide a query framework for indoor LBS, by exploring the connection between decentralized location model and query processing

Query Processing for LBS Location Modeling

Hospital

place entity

Floor 1

Elevator

Nurse

PDA-1

.....

........

Surgery

Roof

device

Helicopter Pilot

Victim

First aider

PDA-2

Query Processing as Dynamic graph search

Query Processing for LBS Approach

1. From Model Checking to Query Processing 2. Hybrid Logic-Based Query Language

Model Checking

Computer-Aided Verification [Clarke et al. , 2000] Goal : to verify that a system satisfies its specification by (1) representing the system as a graph (i.e. Kripke structure) (2) writing the specification in a suitable modal logic formula (3) algorithmically check that the graph is a model of the specification formula

Sucessfully applied in both hardware and software verification • Industrial standard tool for hardware design • Communication & security protocols “Bug-Fixer” • ...... • Foundations for a location query language ?

Model Checking-Based Query Language Computer-Aided Verification

Model Checking

Database

Evaluating Logic Formulas (specification)

Evaluating Logic Formulas (SQL queries)

Finite Structures (Kripke structures)

Finite Structures (Relational Databases) [Negri et al. , 1991]





We propose : (1) Kripke-like Structure, as an extension of the location model itself (2) A Modal Logic-based Query Language

Query Processing for LBS Location Modeling

Hospital

place entity

Floor 1

Elevator

Nurse

PDA-1

.....

........

Surgery

Roof

device

Helicopter Pilot

Victim

First aider

PDA-2

Data Model Hierarchal Space Graph

Hospital

Place

Floor 1

Roof

! Nurse

Elevator

! child 1

! Helicopter

...

! Elevator ! Surgery

! Floor 1 ! Roof

Surgery

Helicopter

! child n ! Pilot ! Victim ! First Aider

R# transition R" transition

! PDA-2

! PDA-1

Nurse

PDA-1

Pilot

Victim

Label

First aider

PDA-2

Query Processing Hybrid Logics • Nominals : propositional variables that are true at exactly one node in the state graph • Access operator : it gives random access to a node of the state graph • Downarrow binder : it creates a brand new name n and assigns it to the current node. q location query q

user's location

...... "here"

location model

Query language Definition

Context

Query

Meaning of a formula = a satisfaction relation connecting the hierarchical graph with the formula.

Query language Semantics

!x

p

p x

Query language Example 1 G, b, hospital |= E↓ surgery

Hospital

Place

Floor 1

Roof

! Nurse

Elevator

! child 1

! Helicopter

...

! Elevator ! Surgery

! Floor 1 ! Roof

Surgery

Helicopter

! child n ! Pilot ! Victim ! First Aider

R# transition R" transition

! PDA-2

! PDA-1

Nurse

PDA-1

Pilot

Victim

Label

First aider

PDA-2

Query language Example 2

Hospital

Place

Floor 1

Roof

! Nurse

Elevator

! child 1

! Helicopter

...

! Elevator ! Surgery

! Floor 1 ! Roof

Surgery

Helicopter

! child n ! Pilot ! Victim ! First Aider

R# transition R" transition

! PDA-2

! PDA-1

Nurse

PDA-1

Pilot

Victim

Label

First aider

PDA-2

Implementation Prototype Architecture

Interaction Shell Context

Query Evaluation

Location Query

Current Location

Tree Graph Networked-Files Tree Structure

Binders

Checkery Core System

HL Model Checker

Query Parsing

OCAML Runtime

Model Builder

Conclusion Roadmap

• Experiments in a real environment (museum) • From static to dynamic locations • Security policy • Access control mechanisms • Privacy • Human-readable query language encapsulation • GUI for mobile search

References

“Stand on the shoulders of giants” [Negri et al. , 1991] M. Negri, G. Pelagatti and L. Sbattella, Formal Semantics of SQL

Queries, ACM Trans. on Database Systems, vol.16, no.3, pp.513-534, ACM Press, 1991.

[Clarke et al. , 2000] E. Clarke O. Grumberg, D. Andpeled, Model Checking, MIT Press, 2000.

[Franceschet et al. , 2004] M. Franceschet, A. Montanari and M. de Rijke, Model Checking for Combined Logics with an Application to Mobile Systems, Automated Software Engineering, vol.11, no.3, pp.289-321, Kluwer Academic Publishers, 2004.

[Becker et al. , 2005] M. Bauer, C. Becker and K. Rothermel, Location Models from the

Perspective of Context-Aware Applications and Mobile Ad Hoc Networks, Personal and Ubiquitous Computing, vol.6, no.5-6, pp.322-328, Springer-Verlag, 2002.

[Areces et al., 2005] C. Areces and B. ten Cate, Hybrid Logics, Handbook of Modal Logic, P. Blackburn, F. Wolter and J. van Benthem, ed., 2005.

Questions

?

Overview

Pyramidal Presentation

Thank You ! Query Processing Location Modeling Context and Location-Awareness Ubiquitous Computing