Using knowledge in model-based software development

Enn Tyugu

Institute of Cybernetics of Tallinn University of Technology

Why another SW technology?

• Software engineering (SE), being often a part of the development of high-tech products, still lacks high-tech tools for its own usage. Much manual and routine work has to be performed in order to get a software product.

• Software development is a knowledge-intensive process, but knowledge usage is little supported by the technology.

SW technologies

Waterfall:

Reqirements spec.

Design

Implementation

Testing

Spiral:Req. spec.

Design

Implementaion

Testing

Agile (XP):Req. & architecture

Impl. Impl. Impl. Impl.

Testing

Model-Based:

Domain engineering

Application engineering

Model-Based SW Technology

Domain engineering Software assets

Application engineering Application

(Domain knowledge acquisition)

(Domain knowledge application)

Software assets

Software assets are the reusable resources used in application engineering:

• Domain specific language (textual and visual)• Domain specific SW components• Domain specific models

History

• Simula

• FGCS and Prolog

• Knowledge-based system projects

• Using metamodels

Best of existing MBSE

• Simulation tools: Simulink, ...

• NASA ISS SW technology

• Visual modeling tools: EMF, MetaEdit, ...

• UML-based methods

Using metamodels

This approach includes the usage of UML-based models and metamodels. It concentrates either on

• research of transformation rules for transforming an initial specification (a model) into another model or an executable code

• or development of rules that represent the operational semantics that enables one immediately to perform the required computations.

Dynamic metamodeling example

SyntaxDefinition

Metamodel

Semantics Definition

Semanticmetamodeling

Runtime metamodel

Operational rules

Graphtransformation rules

Expression

Model

Transition System

States

conforms to

conforms to conforms to conforms to

typedover

semanticmapping

Gregor Engels

What is needed?

• Knowledge representation and handling methods• Easy access to conventional programming tools --

a general purpose programming environment• DSL implementation tools• DSL application environment

What is critical?

• Using knowledge for getting automatically a program (or computations) out of available material (from the assets) that are specs, components, models, ... .

• If this is achieved, then – the program will be bug-free with respect to its

specification (model and goal)– considerable amount of routine work (coding) will be

avoided– maintenance and amendment of programs will be

easy.

Cooke, D. E., Barry, M., Lowry, M., Green, C. NASA’s Exploration Agenda and Capability Engineering. IEEE Computer, vol 39, no. 1, 2006.

Requirements for development • A crucial part of the model-based software development is

automation of the usage of software assets in the application engineering phase. If we consider the result of the application engineering just as a program, then we can say that an efficient program synthesis method that uses the knowledge must be available.

• A tool developed in this way should be supported by a software technology that must have sufficient advantages compared to the existing and widely used ones. (Consider all efforts already invested in the development of various software technologies, e.g. the UML-based ones.)

• To become a generally applicable technology, model-based software development must provide at least the same programming support as the existing general purpose frameworks (Java, .NET etc.) give us.

Ideas for development 1

• A way to achieve this is to develop a framework that merges knowledge-based technique with general purpose programming.

• One can imagine building a knowledge-based tool on top of Java by extending the Java language, for example, just with comments that include the knowledge usable by the tool. Doing this, one should carefully preserve all Java possibilities for program development.

Ideas for development 2

• A tool can be useful only if it adds essential features to the existing platform. These features could be: visual development of models (specifications), user friendly knowledge representation means, easy debugging of large knowledge-based software components, automatic composition of large programs from specifications (models).

• Knowledge-based part and procedural part of the system may have separate name spaces. Only method names of classes should be used in the KB part of a class.

• All Java types (including reference types) should be available in the KB part.

Example domain

Let us take an electrical engineering domain – alternating current cicuits as an example. Domain analysis gives us the following required concepts: – Complex numbers

mod 2 = re 2 + im 2

mod * sin(arg) = im

– Complex values of current i, voltage u, impedance z and conductivity g that will depend on frequency f or cicular velocity ω, where ω = 2 π f.

– Elements of circuits: branch, resistor, capacitor, inductivity– Fragments of circuits: series and parallel connection of subcircuits

(branches)– Some instrumetation components: frequency characteristics,...

im

arg

mod

re

The first concept descriptionWe need a knowledge representation language convenient for engineers, i.e a language that that includes equations. Here is an example of this language.

import java.util.*;class Complex {/*@ specification Complex { double re, im, arg, mod; mod^2 = re^2 + im^2; mod * sin(arg) = im;}

@*/}

More conceptsclass Branch { /*@ specification Branch {

Complex z, i, u, g;double f;u.mod = i.mod * z.mod;u.arg = i.arg + z.arg;g.mod * z.mod = 1;g.arg + z.arg = 0;const double PI = Math.PI;

}@*/}

class Resistor extends Branch { /*@ specification Resistor super Branch

double r;z.re = r;z.im = 0;

}@*/}

class Capacitor extends Branch { /*@ specification Capacitor super Branch {

double omega, C;g.re = 0;g.im = omega * C;omega = 2 * PI * f;

}@*/}

class Inductor extends Branch { /*@ specification Inductor super Branch

double omega, L;z.re = 0;z.im = omega * L;omega = 2 * PI * f;

}@*/}

Fragments of circuits

class Par extends Branch { /*@ specification Par super Branch {

Branch x1, x2;

g.re = x1.g.re + x2.g.re;g.im = x1.g.im + x2.g.im;

u = x1.u;u = x2.u;

f = x1.f;f = x2.f;

}@*/}

class Ser extends Branch { /*@ specification Ser super Branch {

Branch x1, x2;

z.re = x1.z.re + x2.z.re;z.im = x1.z.im + x2.z.im;

i = x1.i;i = x2.i;

f = x1.f;f = x2.f;

}@*/

}

A real program componentpublic class Process {

/*@ specification Process {double inp, out;void res;double min, step, max;Port port;alias draw = (*.drawing_ready);

[ inp -> out, draw ], min, step, max -> res {proc_run};}@*/

public void proc_run(Subtask st, double start, double step, double finish) {

try { for (double i = start; i <= finish; i+=step ) {

Object[] out = st.run( new Object[]{i});}

}catch (Exception e) {

e.printStackTrace();

} }

}

The circuits DSLres resistance r

capacitor capacity C

inductor inductivity L

ser Branches x1, x2

par Branches x1, x2

process a loop for out from min to max with increment step

portinout

A model

Solving a problem

Automatic program construction Structural synthesis of programs (SSP) is a way to get programs

completely automatically from equations and Java methods. It uses reasonably simple model specifications, where component specifications

(si,1si,2…si,ki(Ui,1(si,1)Ui,2(si,2) …Ui,ki(si,ki) Vi(i(si,1,si,2,…si,ki))) )

1≤i≤m u1u2…uk(X1(u1)X2(u2) …Xk(uk) Y(F(u1,u2,…uk, 1, 2,… m)))

are represented in a simpler (propositional) form

(Ui Vi{i}) (X Y{F}) or quite often even X Y{F} 1≤i≤m

See: P. Grigorenko, E. Tyugu. Higher-Order Attribute Semantics of Flat Declarative

Languages. Computing and Informatics. v.28, No. 2, 2010; E. Tyugu. Grigori Mints and Computer Science. In: S. Feferman, W. Sieg, V. Kreinovich, V.

Lipschitz, Ruy de Queiroz (Eds.) Proofs, Categories and Computations: Essays in honor of Grigori Mints. Dov Gabbay’s College Publications, 2010.

Benchmarking of the synthesizer

(Y1&G1 A1) B1,(A1 (B1&G1&Z1)) X1,Y1&X1&U1 A,Z1 ↔ B2,Y1 ↔ U2, ...(Yn&Gn An) Bn,(An (Bn&Gn&Zn)) Xn,Yn&Xn&Un An,Zn-1 ↔ Bn,Yn-1 ↔ Un,

U1&Zn ├ B1;

where n > 1

n=2 n=4 n=6 n=10

SSP Prover <0.01 0.05 36.24 --

STRIP(check) <0.01 0.34 3781 --

STRIP(prove) <0.01 -- -- --

iLeanCoP 0.01 -- -- --

iLeanSeP 0.02 -- -- --

PITP <0.01 0.05 15.73 --

LJT <0.01 0.05 35.15 --

Gandalf 0.01 0.19 0.53 7.55

P. Grigorenko. Higher-order attribute semantics offlat languages. Ph. D. TUT, 2010.

The technology

Components (4)

Specification (scheme or text) (6)

Logical formulae (7)

Algorithm (8) Executable code (9)

Domain engineering

Application engineering

Automatic steps

Project ontology (1)

Requirements (5)

Code components (classes) (2)

Visual rerpesentation (3)

The domain engineering technology

• Problem(s) analysis, use cases

• Domain analysis:– Domain concepts– Domain ontology, incl. inheritance and part-of

relations between the concepts– Problems-related concepts– List of components– Computational content of components.

The tool: CoCoViLa CoCoViLa is a software tool for model-based

software development with a visual language support that performs automatic synthesis of

programs from logical specifications. It is tightly integrated with Java: it is written in Java, uses

advanced features of Java, and it supports programming of new software components in

Java almost without restrictions.

http://www.cs.ioc.ee/cocovila

Support of domain and application engineering

CoCoViLa consists of two runnables: Class Editor and Scheme Editor.

• The Class Editor is a tool for domain engineering, it is used for implementing visual languages for different problem domains.

• The Scheme Editor is a tool for application

engineering -- drawing schemes, compiling and running programs defined by scheme and a goal.

Rich components

B

A component “Boiler”:

Boiler.gif

... .xml

Boiler.java

BoilerDaemon.java

Rich component(metaclass, visual class)

Rich component is a description of a domain-specific concept used for describing models. It is a class, extended with information needed for automatic usage of the class, and also for visual handling of instances of the class. It is therefore also called visual class. A rich component may have four parts:

• visual part – its image, pop-up window etc. • specification (a logical part) • program component • daemon (a permanently running thread).

Package

Package is a collection of rich components and schemes related to an application domain, collected in a package folder and supplied with a package description file in xml format.

A package supported by the Scheme Editor is an implementation of a domain-specific language.

Specification language

1) Declaration of variables type id, id, ...; The type is a primitive type, a class, or a metaclass. Examples:int i,step;Boiler b;

2) Binding a = b;Binding is an equality, where a, b are variables.

3) EquationExample: x = 2* y*sin(alpha);

Specification language continued

3) Axiom

precondition -> variable{name-of-method}

Example:

x,y -> z{P}

This axiom specifies that a method P can be used for calculating z

int P(int a, int b) {…}

4) Alias

alias name = (list of names);

Examples:

alias state = (*.state);

alias in = (x1, x2);

A real application: security exprt system

J. Kivimaa, A. Ojamaa, E. Tyugu. Managing Evolving Security Situations. MILCOM 2009: Unclassified Proceedings, October 18-21, 2009, Boston, MA. Piscataway, NJ: IEEE, 2009, 1 - 7.

Appliaction: simulation in mechatronics

Grosschmidt, G.; Harf, M. (2009). COCO-SIM - Object-oriented Multi-pole Modelling and Simulation Environment for Fluid Power Systems. Part 1: Fundamentals. International Journal of Fluid Power, Vol. 10, No. 2, 2009, pp. 91 - 100. Part 2: Modelling and simulation of hydraulic-mechanical load-sensing system. International Journal of Fluid Power, Vol. 10, No. 3, 2009, pp. 71 - 85

Application: composition of services

R. Maigre, P. Küngas, M. Matskin, E. Tyugu. Handling Large Web Services Models in a Federated Governmental Information System. Proc. 3-rd International Conference on Internet and Web Applications and Services. IEEE Computer Society & CPS, 2008, p. 626 – 631