Novel Component Middleware for Building Dependable Sentient Computing Applications

Maomao Wu, Adrian Friday, Gordon Blair,Thirunavukkarasu Sivaharan, Paul Okanda, and Hector Duran LimonLancaster University

Carl-Fredrik SørensenNorwegian University of Science and Technology

Gregory Biegel and René MeierUniversity of Dublin, Trinity College

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Introduction

Advances in Ubiquitous ComputingNovel applications without direct human

control Intelligent vehiclesTraffic management systemsSmart working/living environment

Activity from automobile industryBMW, DaimlerChrysler, General Motors,

etc.

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Research Challenges

Application requirements Sentience or context-aware Autonomy Decentralisation Proactivity Adaptivity Time and Safety Criticality

Appropriate computational model Programming abstraction Middleware support

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CORTEX Project

EU funded collaborative projectCO-operating Real-time senTient objects:

architecture and EXperimental evaluationUniversidade de Lisboa (Portugal)Lancaster University (United Kingdom)Trinity College (Ireland)Universität Ulm (Germany)

Sentient object modelMiddleware and demo application

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Sentient Object Model

Consume Produce

Sensory Capture

and Fusion

Context Representation

Inference Engine

Sensor

Sensor

Actuator

Actuator

Sentient Object

Event

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Component Model (1)

Dynamic configuration and reconfiguration OpenCOM

Is built atop of a subset of Microsoft’s COM Keeps COM’s core feature

Binary level interoperability standard Microsoft IDL COM’s globally unique identifiers IUnknown Interface

Fundamental Concepts Interface: a unit of service provision Receptacle: a unit of service requirement Connection: binding between interface and receptacle

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Component Model (2)

OpenCOM standard runtime Manage the creation and deletion of components Act upon requests to connect and disconnect components A system graph of running components is maintained to

support the introspection of a platform’s structure Component Frameworks (CFs)

“collections of rules and interfaces that govern the interaction of a set of components plugged into them”

Targeted to a specific domain Publish-Subscribe CF, Context CF, Resource and QoS

Management CF.

http://www.comp.lancs.ac.uk/computing/research/mpg/reflection/opencom.php

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Publish-Subscribe CF

A componentised prototype of the STEAM P-S system Implicit event model for mobile and ad-hoc network

environments Decentralised approach: does not rely on the

presence of any separate infrastructure Event filtering: subject, content, and context. Event are represented in XML, and an XML profile

defines the generic event dialect Underlying communication

Group communication CF: probabilistic ad-hoc multicast protocol, IP-multicast based protocol, and a local (shared memory based) group communication protocol

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Context CF (1)

Sensor capture and fusion Multivariate Gaussian modelling Bayesian networks Dead-reckoning

Inference engine A program that reasons about a set of rules (a

knowledge base) in order to derive an output. The knowledge is encoded as a set of production

rules, contexts are represented as “fact”. CLIPS – C Language Integrated Production

System, its internal implementation is based on RETE net.

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Context CF (2)

CLIPS rule sample

The paradigm facilitates uniform treatment of both context and QoS Rules to trigger adaptations and actuations based on

changes in measure of QoS data CLIPS DLL and OpenCOM component for

WinXP and WinCE

(defrule rule-obstacle-near "CLIPS rule for obstacle near" (car-id (id ?id)) ?f1 <- (obstacle (distance near)) => (retract ?f1) (publish ?id stop))

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Autonomous Cooperative Vehicles

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Demo Application

Vehicles travel on virtual circuitsPredefine a set of GPS waypoints

Second car follows the leading oneCollision avoidanceObey traffic light rulesPedestrian/obstacle detectionQoS adaptation: network coverage

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Software Components Configuration

Ultrasonic Sensor

GPS Sensor

Consume Produce

Steer Actuator

Speed Actuator

Digital Compass Sensor

Other Vehicle Sentient Object

Software Event

Interface

Component

Receptacle

Ultrasonic Fusion 2

Obstacle Sensing Service

Location Sensing Service

Direction Sensing Service

Ultrasonic Fusion 1

GPS Fusion 2

GPS Fusion 1

Digital Compass

Fusion

Inference Service

CLIPS Inference Engine CLIPS

rule files

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Concluding Remarks

The sentient object model has proved to be an excellent programming abstraction for

the development of real-time, cooperative, context-aware applications.

The component-oriented approach offers benefits of flexible configuration and reconfiguration of

the middleware components, supporting the development of context and QoS adaptive applications.

The middleware architecture also provides the management of non-functional concerns

such as timeliness and reliability properties. Our middleware is reusable

we are keen to investigate the generality of our approach by applying our middleware to other application domains involving embedded autonomous components.