Introduction to Modeling (Modeling 1) - Universitetet i Oslo · Introduction to Modeling (Modeling...

INF 5150

29-Aug-14 INF5150 – Unassailable IT-systems 1

Introduction to Modeling (Modeling 1)

What is modeling? Motivation (Edward A. Lee's slides)

ICU0 and ICU1 Version 140829

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Øystein Haugen <[email protected]> University and Research Inst. 80-81: UiO, Research assistant for

Kristen Nygaard 81-84: Norwegian Computing

Center – Simula-machine

97: Practitioners’ verification of SDL systems (Dr. scient.)

98-03: Ifi, UiO as Part time Associate Professor

04-07 : Associate Professor at Ifi (100%)

07- : Senior Researcher SINTEF – Projects on modeling languages e.g. for

variability, train control and pay rolls

07- : Assoc. Professor at Ifi (20%) 10: General Chair MODELS 2010 12 - 15: VARIES (Variability),

Arrowhead (Cyber-Physical), DREAMS (Mixed Criticality)

Industry and Standardization 84-88: SimTech, typographical

applications 88-90: ABB Technology

– SDL, prototype SDL tool, ATC

91-97: Independent Consultant 96-00: Rapporteur ITU for MSC 97-03: Ericsson, NorARC 99-11: OMG wrt. UML 2.0

– Responsible for UML 2.x chapter on Interactions

09 - 13: OMG CVL – Common Variability Language

– Coordinates joint submission team

29-Aug-14 INF5150 INFUIT Haugen / Stølen 2

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What's a Model?

3

Term Phenomenon

Concept

UML1

Mathematics and Physics

Models@runtime

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Modeling a system

A system is a part of the world – which we choose to regard as a whole, separated from the rest of

the world during some period of consideration, a whole which we choose to consider as containing a collection of components, each characterized by a selected set of associated data items and patterns, and by actions which may involve itself and other components

Mental systems – Systems existing in the human mind, physically materialized as

states of the cells of our brains

Mental and manifest models – when a limited set of properties is selected from a system

These definitions are from K. Nygaard and his DELTA team (in 1977)

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Modeling levels revisited

5

Referent system

System reporter

System description

System Generator

Model System

Language Meta Language

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FORTRAN Algol Pascal

C Norwegian Computing Center

SIMULA (Nygaard, Dahl)

Xerox PARC SmallTalk (Kay)

Apple MacIntosh

OOA(Yourdon)

Objectory (Jacobsson) Booch

OMT (Rumbaugh)

UML 1.x (Rational/OMG)

SDL-88

Microsoft Windows

Hoare-logic

CSP Hoare Jones

VDM Milner CCS

LOTOS (ISO)

COBOL

SQL

ER-model

SDL-92 (ITU)

Bell Labs C++

Sun

OODB

JAVA

A history of modeling languages

Broy/Stølen Focus

Corba

UML 2.0 (OMG)

SDL-2000 (ITU)

MSC-2000 (ITU) EJB Web services

MSC-92 (ITU) ROOM

(Objectime)

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The founding fathers





Apple MacIntosh

OOA(Yourdon)


OMT (Rumbaugh)


SDL-88

Microsoft Windows

Hoare-logic

CSP Hoare Jones

VDM Milner CCS

LOTOS (ISO)

COBOL

SQL

ER-model

SDL-92 (ITU)

Bell Labs C++

Sun

OODB

JAVA

Broy/Stølen Focus

Corba

UML 2.0 (OMG)

SDL-2000 (ITU)


MSC-92 (ITU) ROOM

(Objectime)

Conceptual base of OO: Classes with Inheritance, Polymorphism (virtual), Co-routines Garbage Collection

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Making OO Popular and Commercial





Apple MacIntosh

OOA(Yourdon)


OMT (Rumbaugh)


SDL-88

Microsoft Windows

Hoare-logic

CSP Hoare Jones

VDM Milner CCS

LOTOS (ISO)

COBOL

SQL

ER-model

SDL-92 (ITU)

Bell Labs C++

Sun

OODB

JAVA

Broy/Stølen Focus

Corba

UML 2.0 (OMG)

SDL-2000 (ITU)


MSC-92 (ITU) ROOM

(Objectime)

Experimental programming: Runtime checks Graphical in/out

Effective programming and Efficient programs: Explicit memory control

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The Three Amigos





Apple MacIntosh

OOA(Yourdon)


OMT (Rumbaugh)


SDL-88

Microsoft Windows

Hoare-logic

CSP Hoare Jones

VDM Milner CCS

LOTOS (ISO)

COBOL

SQL

ER-model

SDL-92 (ITU)

Bell Labs C++

Sun

OODB

JAVA

Broy/Stølen Focus

Corba

UML 2.0 (OMG)

SDL-2000 (ITU)


MSC-92 (ITU) ROOM

(Objectime)

Visual Language Analysis phase Standardization

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Influences on UML 2.0





Apple MacIntosh

OOA(Yourdon)


OMT (Rumbaugh)


SDL-88

Microsoft Windows

Hoare-logic

CSP Hoare Jones

VDM Milner CCS

LOTOS (ISO)

COBOL

SQL

ER-model

SDL-92 (ITU)

Bell Labs C++

Sun

OODB

JAVA

Broy/Stølen Focus

Corba

UML 2.0 (OMG)

SDL-2000 (ITU)


MSC-92 (ITU) ROOM

(Objectime)

Class diagrams, Use Cases

Internal structure (Parts and Ports) Improved State Machines

Structured Sequence Diagrams Improved Components

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Modeling Needs – It's simplicated

Must be simple yet modeling complicated matters Must be precise but capture fuzzy requirements Must be visual while modeling invisible properties Must be lightweight even when modeling Airbus 380 Must combine domain specific with general, proprietary with

standardized Must be executable and compete with programming Must be dynamical and adaptable at runtime Must be suited for V&V through empirics and analytics Must have tooling that is worth the money Must be taught with enthusiasm and dedication Must be applied by industry especially in times of financial

crisis

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Why make a language?

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Domain Specific Language characteristics

A language is a precise and well-defined way to describe an area of concern – We have a long tradition for making languages and for making

supporting tools and frameworks for that

There are domain specific languages wherever you turn – like the London metro map pioneered by Beck in 1931 – like architectural drawings of buildings and train stations

“Make everything as simple as possible, but not simpler” – General languages are just too much of everything

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The business case for DSLs

“Small is beautiful” – You have full control and rely on nobody

Much easier to make code generation that can produce 100% of the code – because there are few elements and they are all well known to

you

Well documented company-wide understanding – good for bringing new employees into the company

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Why use a general standardized language?

Common terms and interpretation – across persons, teams, companies and cultures

Experience SISU project – Very large SDL specification ported from Alcatel to Kongsberg

Experience MSC – We have a Korean translation of MSC 2000

– across computers! portability Experience Simula

– We ported the exact same code on at least 5 machines without changing a single line of code around 1980

Common teaching material Common libraries Common and open reviewing process

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We will apply modeling for several purposes


Behavioral Requirements of Interaction

Product Lines (Variability)

Executable models

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Disciplined Heterogeneous Modeling

The following slides are borrowed from: Edward A. Lee

Robert S. Pepper Distinguished Professor

EECS Department UC Berkeley

Invited Keynote Talk

MODELS 2010 Oslo, Norway, October 6-8, 2010

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UML Notations: Unified?

[Image from Wikipedia Commons. Author: Kishorekumar 62]

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The Truly Unified Modeling Language TUML

A model in TUML is a function of the form

(notice how nicely formal the language is!)

Tools already exist.

With the mere addition of a TUML profile, every existing UML notation is a special case!

0

h

0 w

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Examples of TUML Models

[Image from Wikipedia Commons. Author: Kishorekumar 62]

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Drawbacks of TUML

Most importantly: It is not standardized (yet)

Models are not executable (but there is nothing new here…) A model may not have the same meaning for all

observers (but there is nothing new here…)

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My [Edward A. Lee's] Claim

Modeling languages that are not executable, or where the execution semantics is vague or undefined are not much better than TUML. We can do better.

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Assumptions of this Talk

I am interested only in executable models (I will not comment about descriptive models)

I focus on concurrent components that communicate via ports (as one might describe in SysML, AADL, or UML Component Diagrams & Communication Diagrams, though my take is more specific than any of these)

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Concurrent Components that Communicate via Ports

An alternative: Actor oriented:

actor name data (state)

ports

Input data

parameters

Output data

What flows through an actor is

evolving data

class name data

methods

call return

What flows through an object is

sequential control

Component interactions in object-oriented programming:

The use of the term “actors” for this dates back at least to the 1970s [Hewitt, Agha, Dennis, Kahn, etc.]

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Examples of Actor-Oriented Modeling Frameworks & Languages from Outside the UML Community ASCET (time periods, interrupts, priorities, preemption, shared variables ) Autosar (software components w/ sender/receiver interfaces) CORBA event service (distributed push-pull) Dataflow languages (many variants over the years) LabVIEW (structured dataflow, National Instruments) Modelica (continuous time, constraint-based, Linkoping) MPI (message passing interface, parallel programming) Occam (rendezvous) OPNET (discrete events, Opnet Technologies) SCADE (synchronous, based on Lustre and Esterel) SDL (process networks) Simulink (continuous time, The MathWorks) SPW (synchronous dataflow, Cadence, CoWare) VHDL, Verilog (discrete events, Cadence, Synopsys, ...) …

The semantics of these differ considerably in their approaches to concurrency and time. Some are loose (ambiguous) and some rigorous. Some are strongly actor-oriented, while some retain much of the flavor (and flaws) of threads.

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First(?) Executable Actor-Oriented Modeling Language The On-Line Graphical Specification of Computer Procedures W. R. Sutherland, Ph.D. Thesis, MIT, 1966

MIT Lincoln Labs TX-2 Computer

Bert Sutherland with a light pen

Partially constructed iterative square-root program with a class definition (top) and instance (below).

Bert Sutherland used one of the first acknowledged object-oriented frameworks (Sketchpad, created by his brother, Ivan Sutherland) to create the first actor-oriented modeling language (which had a visual syntax and a stream-based semantics).

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ICU0 – your very first ”I see you” system

surveillance at your fingertips, first we only observe ourselves

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Tools for executable modeling in INF5150

JavaFrame

UML compiler

UML2

pluginSeDi

PATS Oracle

3.0Windows+

Linux

Commercial big, imperfect

open source – our own executable

modeling

UML 2 runtime system

hybrid systems

third party sw: simple interfaces

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Agile modeling

”agile” – = having a quick resourceful and adaptable character

executable models! very stepwise approach

– each step will have its specification and executable model – each step should be tested

We shall use one example throughout the course – with many steps – intended to be mirrored by the project exercise model

Every week a working program!

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Manifesto for Agile Software Development

We are uncovering better ways of developing software by doing it and helping others do it.

Through this work we have come to value: – Individuals and interactions over processes and tools – Working software over comprehensive documentation – Customer collaboration over contract negotiation – Responding to change over following a plan

That is, while there is value in the items on the right, we value the items on the left more.

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Dialectic Software Development

Software Development is a process of learning – once you have totally understood the system you are building, it is done

Learning is best achieved through conflict, not harmony – discussions reveal problematic points – silence hides critical errors

By applying different perspectives to the system to be designed – inconsistencies may appear – and they must be harmonized

Inconsistencies are not always errors! – difference of opinion – difference of understanding – misunderstanding each other – a result of partial knowledge

Reliable systems are those that have already met challenges

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Buzzzzz 1: Agility – Pros and Cons

Give reasons for why agile modeling/programming is a good approach

Give possible problems for an agile approach

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UML Use Cases – very very simple

subject : our system

use case: a service

actor: the outsiders

note: an informal text

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Use cases in a separate package

Diagram

Package

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UML Sequence Diagrams: a more precise way

Interaction

Sequence diagram

Lifeline

Message

State inv.

Signature

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Packages, Collaboration, Composite Structure Package

Collaboration Composite structure

Part

Port

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Run validation !

Model-time Consistency!

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Structure hierarchy

Part

type

Part

type

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A State Machine defining the system behavior

local variables

State

Initial

Decision

Transition Trigger

Effect

Guard

State machine

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JavaFrame action language

In principle all java can be used – but we try only to use simple constructs – we prefer to use Activity constructs for loops/choices etc.

output (Signal, Port, csm) – sends a signal through a local port. – typically the signal is like ”new S(parm1, parm2)” – typically the port is like ”csm.toSomewhere” – ”csm” is like a keyword meaning ”current state machine”

To read from the most recent consumed signal, use ”sig” – sig has been cast to the right type (normally) – Example: ”sig.parm1” when sig is consumed as object of class S

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Transition Effect – Activity Diagram

Initial

Opaque Action

where the name is

java code

Control flow Final

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Runtime Consistency!

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KML: using GoogleEarth to place mobiles

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Testing ICU0

by using the UML Testing Profile

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Testing is …

A technical process

Performed by experimenting with a system

In a controlled environment following a specified procedure

With the intent of observing one or more characteristics of the system

By demonstrating the deviation of the system’s actual status from the required status/specification.

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Goals of the UML Testing Profile

Definition of a testing profile to capture all information that would be needed by different test processes

– To allow black-box testing (i.e. at UML interfaces) of computational models in UML

A testing profile based upon UML 2.0 – That enables the test definition and test generation based on structural

(static) and behavioral (dynamic) aspects of UML models, and – That is capable of inter-operation with existing test technologies for black-

box testing Define

– Test purposes for computational UML models, which should be related to relevant system interfaces

– Test components, test configurations and test system interfaces – Test cases in an implementation independent manner

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Test Case

Test Concepts: Black-Box Testing

Stimulus Response

System Under Test (SUT)

Port

• Assignment of a Test Verdict

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ICU0 test context test package imports

def of system

System Under Test

Test component

Test case

Test case

returns

Test configuration

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Test context and system context are similar

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Test behavior and context behavior are similar

Verdict Verdict

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Why both context behavior and tests?

Why do we need tests when we have context behavior – We do not always only want pass verdicts

we could also use the neg fragments in Sequence Diagrams – We may want more tests than context behaviors

Tests should be explicit – Identify the SUT and the Test components

this distinction is not done in the context behavior sequence diagrams

– Clearly specify the verdicts context behaviors usually specify potential positive behaviors only

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How to execute the tests

Generated test components – we could specify the behavior of the test components – then compile and run the total test management system – and have the tool verify the test cases by comparison

Manual execution on real environment – you operate the mobile phone, and observe the resulting SMSes – you observe also the GoogleEarth results – Disadvantage: slow procedure since you need to physically move – Advantage: it is the real thing

Manual execution on simulated environment – FakePATS made by Frank Davidsen – Advantage: quicker turn-around, easier manipulation, cheaper

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fakepats.jar is also a stand-alone program!

Actor

Tel. no.

Bus 37 route Bus stop

Send SMS from actor

Start fakepats, then application

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The verdict of the fake mobile

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Verdict of GoogleEarth

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About operations and methods (ICU1)

In order to keep the low-level java code away from the beautiful symbols of our UML

models, we may want to separate some of the nitty, gritty details in out in chunks

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We will introduce operations/methods

parsepos

deccoords

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UML distinguish between operation and method

parsepos – the method

parsepos – the operation

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