ubiquitous computing and active spaces the gaia approach fabio kon [email protected] department of...

Ubiquitous Computing and Active Spaces

The Gaia Approach

Fabio [email protected]

Department of Computer ScienceUniversity of São Paulo, Brazil

http://www.ime.usp.br/~kon

University of Tromsø 2

Ubiquitous Computing

“We believe that people live through their practices and tacit knowledge so that the most powerful things are those that are effectively invisible in use”.

“For 30 years most interface design, and most computer design, has been headed down the path of the ‘dramatic’ machine”.

Mark Weiser


Active Spaces

“This is a challenge that affects all of computer science. Our preliminary approach: Activate the World”.

Mark Weiser

Active Spaces: Physical spaces augmented with computing devices and software to enhance its capabilities.

Examples: offices, lecture and meeting rooms, homes, hospitals, campuses, airports, cities, highways, ...


Priority #1:Managing Dynamism

Mobile users Mobile devices Mobile Software Evolving Software

new component versions new configurations

Evolving Hardware Replacing old devices by new ones Reconfiguring devices


Our Approach

2K Network-Centric OS: a meta-OS that provides support for any kind of dynamic, heterogeneous environment.

Gaia: provides services directly related to supporting physical active spaces.


The 2k Network-Centric OS

Runs as middleware on top of Solaris, Linux, Windows.

Goal: Facilitate the management of dynamic, heterogeneous systems by developers, system administrators, and users.


Scope of 2K Research

1. Interoperability (IDL, CORBA, reflective ORBS, minimal ORBs)

2. Naming and Trading (OMG standard)

3. Component-based services and

applications

4. Dynamic (re)configuration

5. Security and Privacy


Scope of 2K Research

6. Distributed Resource Management7. Quality of Service8. Monitoring9. Fault-Tolerance

But, remember: Not all these features are required all

the time. So, configurability is the key.


Gaia: Getting Physical

In addition to the 2K functionality, must have: Federation of Name Servers and Traders Framework to represent heterogeneous

devices Data Object Service Location Service (for things that move) Event Service Discovery Service Security Service Bridges/adapters to other models (e.g. Jini)


Representing Physical Spaces


Using the Trader FederationTo Locate Devices

printerOffer =

DCLTrader->query(“printer”,

“Postscript == True and PagesPerMinute > 10”,

“min (Price)”);

myPrinter = printerOffer.reference;

myPrinterProperties = printerOffer.properties;

myPrinter->print (myFile);

cout << “Your file is being printed in room ” << myPrinterProperties[ROOM] << endl;


Framework for Representing Heterogeneous Devices

Plan9 and UNIX use a single FILE interface for accessing all devices. Many times this is not appropriate.

Other extreme: having an independent interface for each new device. Difficult to manage and to program.

Intermediate approach: Object-Oriented Framework for

Devices.


Inheritance Diagram for Active Space Entities


The Data Object Service

Christopher Hess (Illinois) inspired by Francisco Ballesteros (Madrid).

Motivation: Growing use of heterogeneous devices connected

to a single global network, accessing the same data.

Some devices possess limited resources and may not be able to render data in original format.

Using an Adaptable Data Service devices access data source in the format they require.

Service handles complex tasks ordinarily left to the application developer.


Data Object ServiceOverview

Applications open data as desired type dynamically typed file system.

Information delivered as data objects. Data sources represented as

containers. Access to data gained via iterators. System sets up data flow paths. Modules in flow path may alter data.


MPEGContainer

MPEG

WordContainer

Word

Example

GrepProcessor

Pixel2BitmapConverter

Text2AudioConverter

GIF2PixelConverter

GIF2PixelConverter

Pixel2BitmapConverter

BitmapContainer

AudioContainer

PixelContainer

MailContainer

PowerPointContainer

MailPowerPoint

BitmapContainerGrepContainer


Architecture Overview

ContainerManager

[room]Layout

Manager

XML Database

Application

Component Repository

ClientLibrary


Container Categories

File containers – access to native operating system files.

Processor containers – files with “dynamic content”.

Converter containers – transform content.

Partition containers – creates chunks for “streamable” containers.


Path Generator

Interface Map

Converter/Processor Containers

bitmap

pixelBitmapContainer

MPEGContainer

PowerPointContainer

PixelContainer

ByteContainer

DirectoryContainer

WordContainer

TextContainer

FileContainers

dirent

byte

.ppt

*

.mpg

.gif

gif

mpeg

.txt

.doc

text

ByteContainer

DirectoryContainer

TextContainer

WordContainer

GIF2PixelContainerPixel2BitmapConverter

MPEGContainer

GIF2PixelConverter PowerPointContainer


Uses of Containers

Data storage – files and directories. Devices - printer, whiteboard, X10. Shared memory - tuple spaces. Proxies – remote transformations. Change interfaces of data sources –

whiteboard to mouse. Services – news.


Ongoing Work

Port to small devices (e.g., PalmPilot).

Dynamic placement for load balancing.

Streaming of container contents. Use as location-specific storage:Layout

Manager


Gaia Kernel Discovery Service

Tracks entities entering and leaving the space: Software Components People Physical entities

Keeps information about active entities

Exports information using the Event Service.


Stores and exports information about entities contained in the space.

Automatically updates a trading service with entity information (includes object reference). Keeps a list of entities up-to-date by

listening on the Discovery Channel. At bootstrap, parses an XML file containing

a list of entities to be started automatically.

Gaia Kernel Space Repository


Gaia Kernel Security Service

Binny Gill and Prashant Viswanathan: Authentication and Credentials

Access Control

Secure Loading of Components

Secure Bootstrapping of Active Spaces

Tracking and Privacy



Authentication: In an ubiquitous computing environment

different mechanisms of authentication will exist

Swipe Cards. Smart Badges. Fingerprinting, Voice recognition, etc. Traditional login/password authentication.



Authentication: Problems addressed

Delegation of authority to trusted programs. Delegation of authority to untrusted

programs. Simple authentication – a user authenticating

himself to a service

Mechanisms Credentials: Generic, Restricted and Non-

Delegatable.



Access Control: Users can be assigned:

Roles and Role Attributes. (student , new employee)

Value Attributes. (Age = 23)

Policies for resources: Specified in terms of roles and attributes. Support method-level policies. Associated with every resource and are used by

the Access Control Service in conjunction with credentials to grant/deny access.



Secure component loading:

All components are downloaded from a Component Repository and are loaded in a Component Container.

Policies in the Component Container determine which user can load components within it.

The Component Repository also has policies associated with it determining which user can upload/download components.

Components can be signed to verify authenticity.



Secure bootstrap (two levels):

First Level consists of boot-strapping Security Services, Naming Service and other basic services.

The services started in the first level constitute the Trusted Computing Base for GAIA.

Second Level boots an active space after verifying the integrity of the first level.


Gaia KernelSecurity Service

Tracking and privacy:

Tracking: the system is aware of the location of users and devices.

Privacy: the location information should not be made public unless explicitly desired by the user.


UIC:Universally Interoperable Core

Component-based communication middleware by Manuel Román (Ubicore)

Motivation Ubiquitous Computing requires a very

flexible and dynamically configurable distributed object model (e.g. dynamicTAO).

But CORBA (and dynamicTAO) is too big Unfortunately [?] CORBA is not the only

model


UIC and WYNIWYG

What You Need is What You Get The ORB is broken small components.

Only the required ones are loaded.

Components can be loaded and unloaded dynamically to customize functionality.

Result: the middleware can fit in very small devices.


Different interoperability mechanisms require different object implementations.

Object1

Object1

Object1

Object1

CorbaJavaRMI

SOAP

Current Approach


Changes in the interoperability mechanisms should not affect the implementation of the object.

Object1

Object1

CorbaJavaRMI

SOAP

UIC: Object is Always the Same


Customization

Transport protocol and Connection establishment

Marshaling and demarshaling strategies Memory Management Method invocation protocols Data streaming protocols Method dispatching scheduling Object reference generation and parsing Object registration and method dispatching Client and Server Interface Thread strategies


skeleton

UIC-CORBA UIC-SOAP

Commoninfrastructure

UIC Personalities

UIC-RTP

UIC™-Multipersonality


Assemble the UIC at link time.

No reconfiguration allowed.

Best size results.

Static Configuration


Assemble the UIC at runtime. Replace components at runtime. Reconfigure architecture at runtime. Size increases (dynamic manipulation

infrastructure). Recommended for dynamic scenarios. Service provider can update UIC

remotely.

Dynamic Configuration


UIC-CORBA Sizes

PalmOS Static Library

WindowsCE (SH3 proc.) Release DLL

WindowsNT Release DLL

UIC-CORBA Client-Side

13 KB 24 KB 68 KB

UIC-CORBA Server-Side

31.5 KB 84 KB

UIC-CORBA Client/Server

37 KB 92 KB


Ongoing Work

Integration of all current services in experimental Active Spaces at the U. of Illinois

Sensing / Tracking / Visual Recognition Adaptive Networking Power Management for Mobile Devices Rendering Realistic 3D Models U. São Paulo:

Supporting Adaptive Applications Distributed Information Services for Mobile Users


Project SIDAM:Traffic Information System

São Paulo is a city of 17M people

Street and road traffic is a complete chaos.

Goal: develop a prototype of a very-large-scale

system to provide relevant information about traffic conditions in real-time to mobile users.


Research Topics

Scalability, replication, data consistency Protocols for mobile computing Data obsolescence Dynamic Reconfiguration for

fault-tolerance load balance mobility (change of context) promoting data locality


The Java Prototype

Information Servers (traffic information). Location Servers (a directory service of

Information Servers). ComponentConfigurators manage the

dependencies between ISs and LSs. Also hold information about alternatives. Failure of an Information Server triggers

automatic reconfiguration.


Project SIDAM:Ongoing Work

Trigger automatic reconfiguration when any component in the system fails.

Creation and destruction of Information and Location Servers according to system load.

Migration of components according to load and phisical location of clients.

Goal: increase availability and response time of the Traffic Information System.


For more information

Roy Campbell: [email protected] Kon: [email protected]

2K Web site:http://choices.cs.uiuc.edu/2K

Gaia Web site: http://choices.cs.uiuc.edu/gaia

SIDAM Web site: http://www.ime.usp.br/~sidam

ubiquitous computing and active spaces the gaia approach fabio kon [email protected] department of...

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