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Modelbased approaches for the design of safety critical interactive systems

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Title: Modelbased approaches for the design of safety critical interactive systems


1
Model-based approaches for the design of safety
critical interactive systems
  • Philippe Palanque
  • LIIHS-IRIT
  • University Paul Sabatier
  • Toulouse France
  • http//liihs.irit.fr/palanque
  • palanque_at_irit.fr

Rio de Janeiro 18-19 september 2007
2
Overview of the lectures
  • Overview of LIIHS Research Group
  • State of the art in MBA for HCI
  • System modeling
  • Task modeling
  • Design rationale
  • Research Themes and Productions
  • A Roadmap on FM HCI

3
A bit of History about LIIHS
1 - Overview of LIIHS
  • Started in 1988 at University Toulouse 1 (law and
    economics) gathering all the computer scientists
    at UT1
  • In 1993 main research theme is HCI and name
    changed to LIHS (group size about 15 people)
  • From research on software engineering
    methodologies
  • From research on notations for modeling
    activities
  • 20 PhDs

4
Research at LIIHS
1 - Overview of LIIHS
  • Mono-disciplinary research Human Computer
    Interaction
  • Computer Scientists,
  • Human Factors, Ergonomics,
  • HCI specialists
  • Special point of view Software Engineering for
    Human-Computer Interaction
  • Usability (methods for design and evaluation of
    computer systems)
  • Reliability (formal specification, human error
    assessment, …)
  • Traceability (Design rationale)
  • Special application domain (safety) critical
    interactive systems cost of development much
    lower than the cost of a failure

5
Safety Critical Interactive Systems
1 - Overview of LIIHS
  • Safety Critical Systems
  • Software Engineers
  • System centered
  • Reliability
  • Safety requirements (certification)
  • Formal specification
  • Verification / Proof
  • Waterfall model / structured
  • Archaic interaction techniques
  • Interactive Systems
  • Usability experts
  • User centered
  • Usability
  • Human factors
  • Task analysis modeling
  • Evaluation
  • Iterative process / Prototyping
  • Novel Interaction techniques

6
Modeling
  • Tasks models
  • Abstract description of users' planned activities
    (goal)
  • Scenarios
  • Concrete description of users' planned activities
  • Temporal organization of actions (and related
    information)
  • System models
  • Both structure (object oriented approach) and
    behavioral description
  • How user's actions change system state
  • How system state (rendering)
  • Reduces authorized user's actions
  • Is presented to the user
  • Designing options rationally

7
Research Projects
1 - Overview of LIIHS
  • Current projects
  • ReSIST EU Network of Excellence Project
    (Resilience for Information Society)
    (01-2006/12-2008)
  • COST NSF EU action MAUSE (Maturing Usability)
    (01-2005/12-2008)
  • Recently completed
  • INTUITION Project (Multimodal Interfaces military
    aircrafts) (02-2003/02-2006)
  • MISC Project (Multimodal Interfaces for
    Safety-critical Command and Control)
    (01-2003/01-2007)
  • Research Training Network EU ADVISES (11-2002/
    12-2006)
  • Capes/ Cofecub SPIDER WEB (07-2002/07-2005)
  • Previous relevant projects
  • DoD Drones Project (Unmanned Aerial Vehicles)
    (03-2001/09-2002)
  • EUD-Net EU Network of Excellence
    (07-2002/07-2002)
  • EVALWEB Project Building ergonomic web sites by
    design (1999-2002)
  • Project CNET SERPICO Specifications for CORBA
    Components Engineering (1998-2001)
  • Esprit Project LTR MEFISTO n24963 Modeling
    Evaluation and Formalizing Interactive Systems
    using Tasks and Objects (1997-2001)
  • ERGOVAL (1995)

8
EvalWeb
1 - Overview of LIIHS
  • 1998-2002
  • Ergonomic application web by design
  • Partners Univ. Louvain la neuve (J.
    Vanderdonckt) INRIA (D. Scapin)
  • Funding CNRS GIS Cogniscience (1999)

9
MEFISTO (overview)
  • Modeling, Evaluating and Formalizing Interactive
    Systems using Tasks and interaction Objects
  •  ESPRIT Reactive LTR 24963 Project (EC)
  • Air Traffic Control domain
  • Multi disciplinary team
  • Computer Scientists (F. Paterno CNUCE, LIIHS)
  • Psychologists (P. Wright Univ. York, P. Marti
    Univ. Sienna)
  • Industrial partners (DERA UK, CENA F, Alenia I)
  • Users (ENAV I ATC association)

10
UAV Project (1/2)
1 - Overview of LIIHS
11
UAV Project (2/2)
1 - Overview of LIIHS
  • Design, implementation and evaluation of user
    interfaces for drones command and control
  • Performance and user capabilities
  • Authority sharing
  • From several controllers per drone to one
    controller for several drones

12
MISC Project
1 - Overview of LIIHS
  • Multimodal Interaction for Command and Control of
    Safety critical Systems
  • Starting beginning 01/2003
  • Finances DGA (French Department of Defense ,
    CNES (National center for spatial studies), and
    LIIHS

13
Project SPIDER WEB
1 - Overview of LIIHS
  • Specification and Prototyping for user Interface
    Design, Engineering and Re-engineering for the
    Web
  • France- Brazil cooperation
  • Partners LIIHS and Instituto de Informatica
    (Porto Alegre)
  • Beginning Feb. 2002
  • In conjunction with a CNPq funding of Marco
    Winckler PhD about "model-based approaches for
    wed application evaluation"

14
ADVISES Analysis Design and Validation of
Interactive Safety-critical and Error-tolerant
Systems
  • Type de projet Research Training Network
  • Sponsors EU (Fifth Framework Improving Human
    Potential Programme)
  • 8 sites Delft University of Technology (NL),
    ISTI-CNR(I), Risø National Laboratory (DK),
    Université de Liège (B), Université Paul Sabatier
    Toulouse (F), University of Glasgow (UK),
    University of York (UK), Universität Paderborn
    (D)
  • Objectifs
  • Étudier et développer des méthodes outils et
    techniques pour l'analyse, la conception et la
    validation de systèmes interactifs fiables et
    tolérants aux erreurs humaines
  • Principes
  • Approche pluridisciplinaire intégrant des
    spécialistes facteurs humains (ergonomie
    cognitive, psychologie du travail) des
    spécialistes informatiques (génie logiciel,
    méthodes formelles, approches à objets et
    distribuées) des spécialistes en interaction
    homme-machine (méthodes de conception centrée
    utilisateur) et des spécialistes en systèmes
    critiques (analyse d'incidents/accidents,
    systèmes embarqués civil et militaires,
    nucléaire)
  • Formation à la recherche et par la recherche
  • Formation des jeunes chercheurs dans ces domaine
    par la mobilité au sein du réseau

Durée (4 ans) Oct. 02 ? Oct. 06
Budget LIIHS 160 K HT
15
EUD-Net
1 - Overview of LIIHS
  • The EUD-NET Network of Excellence is financed by
    European Community and started in July, 1st 2002.
  • Goal help the European Commission to prepare a
    research agenda in the end-user development field
  • Related to previous work on notations and tools
    for visual programming

16
Project INTUITION
  • Financed by DoD. THALES avionic in charge. LIIHS
    team 240K HT.
  • Start January 2003. 3 years
  • Definition and construction of a platform for the
    design, specification and development of
    multimodal interactive systems
  • Application domains
  • Rafale Cockpit
  • Air Traffic Control multimodal Interfaces

17
Cockpit Rafale
Visu tête haute
Ecran tactile
Joystick
18
MAUSE Towards the MAturation of Information
Technology USability Evaluation
  • Type de projet action COST
  • Sponsors ESF (European Science Foundation) et
    COST (European Cooperation in the field of
    Scientific and Technical research)
  • 19 pays UE (AT, BE, CY, CZ, DK, FI, FR, DE, GR,
    IS, NL, NO, PL, RO, SI, ES, SE, CH and UK)
  • Objectifs
  • Étudier, développer, évaluer et comparer les
    Méthodes dEvaluation de lUtilisabilité (MEU)s
  • Activités
  • WG 1 Révision et Analyse de (MEU)s
  • WG 2 Comparaison de (MEU)s Stratégies et
    Implémentation
  • WG 3 Validation de Schèmes de Classification de
    Problèmes dutilisabilité
  • WG 4 Révision des approches assistées par
    lordinateurs pour lévaluation de
    lutilisabilité
  • (SIG) E-Learning
  • Dissémination de résultats (Coordination)
    LIIHS-IRIT, P. Palanque, M. Winckler

Durée (4 ans) Déc. 04 ? Nov. 08
Budget Défini en fonctions des missions et des
activités des participants
19
ReSIST
1 - Overview of LIIHS
  • http//www.resist-noe.eu/
  • Resilience
  • Diversity
  • Usability
  • Evolvability
  • Assessability
  • DependabilitySafetySecurityUsability
  • Duration 3 years

20
Members of LIIHS working in that field
1 - Overview of LIIHS
Regina BERNHAUPT Visiting Professor
Joseph Xiong PhD Student 4th year
Jean-François LADRY PhD Student 1st year
Eric BARBONI Post Doc
Florence Pontico PhD Student 4th year
Sandra BASNYAT Post Doc
21
Outline of the presentation
  • Overview of LIIHS Research Group
  • State of the art in MBA for HCI
  • Specificities of Interactive System
  • What is modeling?
  • What kind of modelling in HCI?
  • What has still to be done?
  • System modelling
  • Task modelling
  • Design rationale
  • Research Themes and Productions
  • A Roadmap on FM HCI

22
Interactive Systems
2 State of the art
23
"Classical" Design Process SS
2 State of the art
Informal requirements
Manual
Spec 1
...
Specification
Spec n
Design 1
Design
...
Design n
User testing
Prog. 1
Coding
...
Prog. n
24
What is a "Model" ?
2 State of the art
  • Concepts relationships between concepts
  • Example Entity Relationship Model
  • Concepts Entity types, Relationship Types,
    Attributes, Domain of Values, Identifiers, ...
  • Relationships between concepts "A Relationship
    type is a sub set of the Cartesian product of two
    Entity Type"
  • An entity e1 cannot have more than one
    relationship with another entity e2 through the
    same relationship type

25
What can we Expect from a Model ?
2 State of the art
  • Completeness (we can express all the information
    we need to)
  • Consistency (Contradictory elements cannot be
    expressed)
  • Generality (Independent from a given application
    domain … always ?)

26
What is a "formalism" ?
2 State of the art
  • A set of conventions for representing the
    concepts of a Model
  • Lexical elements (graphical or textual)
  • Concrete Syntax (separators, terminators, ...)
  • A formal definition of these conventions
    (otherwise just a notation)

Person
Flat
0,n
1,1
Owns
27
What can we expect from a "formalism" ?
2 State of the art
  • Expressiveness
  • Conciseness
  • Closeness of the representation to the
    application domain
  • Completeness wrt the Model (counter example
    Graphical formalism of the Entity Relationship
    Model)
  • L. Lamport "the only difficult problem the author
    solved was understanding his own notation"
  • L. Lamport "Automaton is a formal description
    technique dedicated to the specification of
    stacks"

28
Bug With a "Formalism" we build "models"
Modelling
2 State of the art
  • model ideal representation of a given situation
    form the real world restrained to the concepts
    covered by the Model
  • Goal analyze the model to draw conclusions about
    the actual state of the real world
  • Meta-model model representing the concepts of
    the Model using the formalism (done for E/R and
    UML using class diagrams)

29
What and why modeling systems?
2 State of the art
  • An abstract description of the system
  • independent from the implementation
  • that do not deal too early with details
  • Describe what are the outputs of the system
    according to the inputs
  • To allow discussions between the various actors
    (at a time, along the design process)
  • to store results of discussions

30
What is a system model for Interactive Systems ?
2 State of the art
  • Represents the system data and actions
  • Represents behaviour of the system
  • what actions are offered by the system
  • when an action is available (according to the
    state of the system)
  • what is the effect of an action on the state of
    the system
  • Represents both how the system is presented to
    the user and how the user interacts with it

31
Design process for IS ?
2 State of the art
Informal requirements
Manual
Spec 1
Goal 1
User requirements
...
Specification
...
Spec n
Goal n
Design 1
Task 1
Task Analysis
Design
...
...
Design n
Task n
User testing
Prog. 1
Coding
...
Prog. n
32
Why Modelling Interactive Systems Formally ?
2 State of the art
  • To cope with the complexity
  • To avoid a human observer (checking models)
  • To avoid a human translator (writing code)
  • To reason (verification, validation)
  • To meet three basic requirements
  • Reliability generic and specific properties
  • Efficiency performance of the system, the user
    (workload, …) and the couple (user, system) tasks
  • Usability

33
Design process using FM
2 State of the art
Automatic
Informal requirements
Manual
Spec 1
Verification
...
Specification
Spec n
Validation
Design 1
Design
...
Generic properties
Verification
Design n
Informal validation
Coding
Prog. 1
...
Progr.
Gener.
Prog. n
34
The design process of models
2 State of the art
35
Examples of models (requirements)
2 State of the art
  • A need for a declarative formalismRequirements
  • Every clearance sent by a controler to a plane p
    is received by this plane
  • " p Planes, " req DLRequest,
  • AGsend(req,p)AFltreceive(req,p)gttrue
  • A data-link clearance sent by a controler to a
    plane p will only be received by that plane
  • " p,p' Planes, " req DLRequest,
  • AGsend(req,p)AGnot(receive(req,p')true

36
Temporal Logic CTL (Computational Tree Logic
Star)
2 State of the art
  • A state has one or mode successors
  • The set of possible states is infinite
  • Operators
  • A (all the possible future) E (one possible
    future) F eventually, G always, X next, U
    until
  • Logical connectors
  • ? (and) ? (or) ? (not) ? (implies)

37
Temporal Logic CTL
2 State of the art
si
si AGp
si AFp
si
si EGp
si EFp
p formula is true if the system is in red state
false otherwise
38
Temporal Logic CTL
2 State of the art
si
si
si AXp
si EXp
si
si
si E(p U q)
si A(p U q)
39
Relating tasks and system
2 State of the art
Maintain task and system
models consistency
Formal task modelling
Formal system modelling
Preliminary
Preliminary
th
th
system model
i
iteration
i
iteration
task model
Quantitative
analysis
Ok
Towards
Not Ok
Proposals for
Check
Usability
improving the
Objectives
Testing
system model
40
Proving compatibility of models
2 State of the art
  • All the objects in the tasks model are part of
    the data model of the system model
  • All the actions in the tasks model are offered by
    the system model
  • All the actions in the system model exist in the
    tasks models
  • All the sequences of actions in the tasks model
    are "legal" in the system model

41
Fundamental elements for formal methods for IS
2 State of the art
  • Describe both state and events
  • Describe both data structure and control
    structure
  • Provide structuring mechanisms (80 of the code
    is dedicated to UI Myers 90)
  • Take into account concurrency (multimodal
    systems)
  • Deals with temporal aspects (temporal windows)
  • Do it formally (it is easier to prove than to
    test)

42
State versus Events (Dix 91)
2 State of the art
  • Reactive systems
  • Event driven
  • Slicing of code into event handlers require
    explicit state representations
  • Approaches
  • Approaches coming from Reactive Systems
  • Reactive or synchronous languages (esterel,
    Lotos)
  • Methodological use of Petri nets

43
Data Structure / Control Structure
2 State of the art
  • Software crisis has shown limitations of
    separation (maintainability, modifiability,
    reusability, ...)
  • Approaches
  • Mix two dedicated approaches (CSP-Z, Object-Z, …)
  • Integrate two approaches (Full LOTOS, Petri nets
    with objects)

44
Structuring Mechanisms
2 State of the art
  • Handling of complex components
  • Understandability of models
  • Reusability
  • Modifiability
  • Approaches
  • composition (aggregation, association, …)
  • communication (client-server, actors)
  • macros and plugs

45
Concurrence
2 State of the art
  • Concurrency between input and output devices (
    multimodality)
  • Groupware
  • Multi threaded dialogues
  • Approaches
  • Textual formalisms (CSP, CCS, LOTOS, Temporal
    Logic)
  • Graphical formalisms (Petri nets, Statecharts)
  • Only Petri nets feature full concurrency semantics

46
Temporal Aspects
2 State of the art
  • Multimodal systems
  • Animation (time based evolution)
  • Alarms
  • Calendar events
  • Approaches
  • Procedural (Petri nets, Lotos, ... )
  • Declarative (Temporal Logics, ...)

47
Formal Aspects
2 State of the art
  • Easier to prove than to test
  • Critical Systems
  • Completeness, concision et non-ambiguity
  • Executability
  • Approaches
  • Mathematical validation
  • Test case generation
  • Automatic code generation

48
A Small Example/Exercise
  • Model of a Mouse behaviour (one button, no wheel)
  • Model of the interaction technique
  • Click
  • Double click
  • Extensions
  • Several buttons
  • Behaviour of the wheel
  • Several mice

49
A Small Example
2 State of the art
  • Requirement
  • Whatever state the system is in, Move is always
    available

50
A Small Example
2 State of the art
51
A Small Example
2 State of the art
Adding Time
52
A Small Example
2 State of the art
Taking Movements into account
53
State of the Art in FM for HCI
2 State of the art
  • Understanding interactive systems
  • What is an IS ?
  • What are the generic properties of IS ?
  • Specific properties of IS ?
  • Engineering interactive systems
  • What are the components of IS ?
  • How to model components and their relationships ?
  • Relationships with design process ?

54
Understanding IS
2 State of the art
  • Generic architectures for IS
  • PIE and red-PIE models (Dix 91)
  • Seeheim (Green 85) and Arch/Slinky (Bass 92)
  • Generic properties for IS
  • (Sufrin He 90), (Dix 91)
  • External and internal prop. (Gram Cockton 96)
  • Between understanding and engineering
  • CNUCE interactors (Paternò Faconti 92)
  • York interactors (Duke Harrison 93)

55
Engineering IS
2 State of the art
  • Dialogue modelling WIMP
  • (Bastide Palanque 90)
  • (Beck et al. 95)
  • Model-Based UIMS (WIMP) (CADUI'96)
  • UIDE (Foley et al. 93)
  • Tadeus (Elwert Schlungbaum 95)
  • PetShop (Bastide Palanque 95)
  • TRIDENT (Vanderdonckt 95)
  • Design Patterns PAC (Coutaz 87) MVC
  • Model-Driven Interactive Systems Engineering
    (Vanderdonckt 2002, Paterno 2004) targeting at
    multiplatform UI (One model many interfaces)
    Paterno 98

56
Generic properties
2 State of the art
  • Generic properties for Software Systems
  • Liveness
  • Safety
  • Ability to wear
  • Generic properties for Interactive Systems
  • Predictability
  • Observability
  • Reachability
  • Insistence
  • Honesty, …

57
Verification of properties
2 State of the art
  • Observability
  • the system makes all relevant information
    potentially available to the user
  • Insistence
  • the dialogue structure ensures that necessary
    information is perceived
  • Predictibility
  • users can predict future states and system
    response time from current and prior observable
    states

58
References (books)
2 State of the art
  • Formal Methods in HCI, Harrison Thimbleby 90,
    Cambridge University Press
  • Formal Methods for Interactive Systems, Dix 91,
    Cambridge University Press
  • Formal Methods in HCI, Palanque Paterno 97,
    Springer Verlag

59
References (conferences)
2 State of the art
  • Eurographics workshops DSV-IS (Design,
    Specification and Verification of Interactive
    Systems) since 94 published by Springer Verlag
    (LNCS)
  • CHI 96 workshop on Formal Methods and HCI
  • CHI 98 workshop on designing user interfaces for
    safety critical systems
  • CHI 05 SIG on Safety Critical Interaction
  • CHI 07 SIG Beyond Usability for Safety Critical
    System
  • HCI Aero 2000 SUCA (Safety and Usability concerns
    in Aeronautics)
  • Mini-track of World Congress on FM 99
  • FMIS workshop series (Formal Methods for
    Interactive Systems)
  • MDAUI workshop series at MODELS conference
    (formerly UML conference)

60
References (journals)
2 State of the art
  • No dedicated journal
  • Software engineering journals
  • HCI journals
  • Some "special issues"
  • Interacting with Computers vol 9, n3, 1997
  • Journal of Visual Language and Computing (vol 10,
    n3, 1999)
  • ACM Transactions on Computer Human Interaction
    (2001)

61
Research Work carried out at LIIHS
62
Outline of the presentation
  • Overview of LIIHS Research Group
  • State of the art in FM for HCI
  • Research Themes and Productions
  • Formalisms and tools
  • Demos
  • A Roadmap on FM HCI

63
Main Results Relevant to FM in HCI
3 Research results
  • Vilage (work with S. Chatty at CENA)
  • A notation Whizz
  • A case tool Whizz'ed
  • SpiderWeb (work with Marco Winckler)
  • A notation StateWebCharts
  • A tool SWC Environment
  • PetShop
  • A formal notation ICOs
  • A case tool PetShop
  • User-centered design methods
  • Linking tasks, scenarios, system and user models
  • Design rationale (lecture on that topic on
    Wednesday morning)

64
VILAGE (1)
3 Research results
  • Initially developed for Air Traffic Controllers
  • Interactive prototyping of highly interactive
    applications (post-WIMP)
  • Build and test prototypes in a modeless way

65
VILAGE (2)
3 Research results
  • A data flow model
  • A set of basic building bricks
  • Strongly typed connection
  • Event listeners

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66
VILAGE (3)
3 Research results
Tool Palete
Dialogue Zone
Editing Zone
Simulation Zone
67
Overview of the Interactive Cooperative Objects
(1)
3 Research results
  • Petri nets with objects
  • Petri nets inside objects
  • Objects inside Petri nets
  • Petri nets for dynamic aspects
  • Objects for structuring
  • Specific aspects for Interactive Systems
  • Activation
  • Rendering
  • Tool support
  • Editing, Execution, Analysis, Prototyping

68
Overview of the Interactive Cooperative Objects
(2)
3 Research results
  • Set of cooperating classes
  • For each class
  • Behaviour (places and transitions) in the Petri
    net
  • Software Services (availability)
  • States (distribution AND value of tokens)
  • Presentation
  • Rendering function
  • Activation function
  • User services

69
Verification
3 Research results
  • What ?
  • Safety nothing bad will ever happen
  • Liveness something good will eventually happen
  • "Smooth functioning"
  • "good cooperation between Models"
  • Efficiency (both local and global)
  • How ?
  • Based on Petri nets theory (the basic brick of
    our system modelling technique)
  • Cross execution of models
  • Performance evaluation techniques

70
PetShop Fundamental Principles
3 Research results
  • Highly interactive tool support for the ICO
    notation
  • Formal methods can be usable (and useful beyond
    n! calculation)
  • Shortening the Path from Specification to
    Prototype
  • … to practically nothing
  • Model-Based
  • The specification model is embedded and
    interpreted at run-time WYMIWYR (what you model
    is what you run) to reduce gaps in interpretation
    (Norman's model)
  • No Modes no automation surprises
  • The model is editable and interpretable at any
    time
  • Allows for interactive prototyping of new
    interaction scenarios

71
PetShop Architecture
3 Research results
72
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73
Requirements
3 Research results
  • A voice request sent to a plane p is received by
    all the planes in the sector
  • " p Planes, " req VRequest,
  • send (p, req) " p' Planes, receive (p', req)
  • It is not possible to build several orders at a
    time
  • " p Planes, " req, req' DLRequest,
  • AFstart_send(req,p)ATruenot(start_send(req',p)
    U(end_send(req,p)true

74
A demonstration ?
75
ATM in France
3 Research results
  • Systems currently used
  • A radar screen
  • A board of paper strips
  • Limited interaction with the radar screen (zoom)
  • Few systems - a lot of prototypes

76
ATM
3 Research results
77
An Air Traffic Management Case Study Current
System
3 Research results
  • VHF communication
  • all the pilots listen to all the communications
  • limited bandwidth
  • low quality
  • Manual stripping
  • the controller has to write down by hand all the
    information given to pilots
  • only a note pad and an aide memoire

78
Envisioned ATM System
79
A demonstration !
80
User Centered Design Methods
81
User Centered Design Methods
3 Research results
Mapping
A demonstration ?
Input
82
Routine Scenario
3 Research results
  • Several aircrafts in my sector
  • I assume two of them
  • I have to transfer both of them
  • 2 slips then first aircraft transferred
  • Second plane directly transferred

83
A small case study a timer controlled light
switch
3 Research results
  • The system
  • use of a timer controlled switch (30 sec period)
  • very simple
  • hardware based (but same as screen saver)
  • Users goal
  • maintain the light on 3 minuts
  • dont press the button more than necessary
  • Two iterations on the life cycle

84
Task model
3 Research results
  • What ?
  • both activity and planned tasks
  • based on the notion of goal
  • several task models for a given goal
  • sequence of users actions on the system
  • How ?
  • temporal relationships in Petri nets
  • invocation of actions offered by the system

85
User Model
3 Research results
  • Only basic user Models (human processor)
  • Possibility to describe user learning
  • Cooperation and/or merging with tasks and system
    models
  • Currently working on higher level user models
    (ICS)

86
Initial System
3 Research results
  • the light bulb
  • the timer
  • not possible to reach the goal

87
First Improvement
3 Research results
  • Add a stop-watch
  • Require hand and eyes

WatchOff
Press
Press
WatchOn
CurrentTime
lttgt
88
The Task model
3 Research results
t gt 25
T1
ReadyTo
P1
StopWatch
  • Goal reachable
  • Really complex for the user

Watch.Press
CountDown
T2
ReadyTo
StartLight
ReadyTo
P2
P3
P4
StartWatch
Watch.Press
lttgt
Light.PressSwitch
T4
T3
Light
Started
Watch
Started
CurrentTime
P6
P7
P5
lttgt
StartCounting
t lt 25
T6
lttgt
T5
lt0gt
lttgt
T7
ReadyTo
lttgt
t
Watch.CurrentTime
ReadTime
P8
89
Second Improvement
3 Research results
  • Add a bell
  • Remove stop watch

PressSwitch
AutoSwitchOff
5
LightOn,
AutoBeep
Beeping
25
PressSwitch
PressSwitch
90
The Task model
3 Research results
  • Less complex
  • Less pooling

Start/ Elapsed
CountDown
Light.PressSwitch
Waitting
Hear beep
91
User model
3 Research results
  • The perceptual system
  • boundary with the environment
  • eye between 50 and 200 ms (average 100 ms)
  • The motor system
  • physical mouvement
  • hand between 30 and 100 ms (average 70 ms)
  • The cognitive sytem
  • interface between motor and perceptual
  • brain between 25 and 125 ms (average 70 ms)

92
Performance Evaluation of the first System
3 Research results
(0,n,1,1,0,0,0,0)
T3 / ngt1
T4
nn-1
(0,n,0,1,0,1,0,0)
(0,n,1,0,0,0,1,0)
  • based on marking graph of the Petri net
  • based on the previous user model
  • Initial state n7

T3 / ngt1
T4
nn-1
(0,n,0,0,0,1,1,0)
T6
(0,n,0,0,0,0,0,1)
T5
T7
(0,n,0,0,1,0,0,0)
T1
(1,n,1,0,0,0,0,0)
T3 / ngt1
T2
nn-1
(0,n,1,1,0,0,0,0)
(1,n,0,0,0,1,0,0)
T3 / ngt1
T4
T3 / ngt1
nn-1
T2
nn-1
T4
(0,n,0,1,0,1,0,0)
(0,n,1,0,0,0,1,0)
93
Performance Evaluation of the first System (2)
3 Research results
T1
Cognitive
Comparison of values
T2
Motor
Press button (Stop Watch)
T3
Motor
Press button (Light)
T4
Motor
Press button (Stop Watch)
T5
Cognitive
Comparison of values
T6
-
Nothing
T7
Perceptual
Look at the Stop Watch
94
Performance Evaluation of the second System(1)
3 Research results
T1
Motor
Press button (Stop Watch)
T2
Perceptual
Hear the beep
95
Results
3 Research results
  • First upgrade
  • Min Time (Goal) 7165 60 1205 ms
  • Mean Time(Goal) 7380 140 2800 ms
  • Max Time(Goal) 7625 200 4575 ms
  • Second upgrade
  • Min Time (Goal) (830) (750) 590 ms
  • Mean Time(Goal) (870) (7100) 1260 ms
  • Max Time(Goal) (8200) (7100) 2300 ms

96
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