27.08.2007

Stepan Potiyenko

Verification of Specifications in Modeling Languages using Basic Protocols

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Technology overview

Basic Protocols(Hoare triples)

Specialized verification tools (static checking, model checking, …)

manualformalization

Requirements SpecificationsEnglish text

Formal ModelMSC, SDL, UML, ...

automatictranslation

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Agents and Environment

Environment with attributes ab

x

Agent• states• local attributes• behavior

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Basic Protocols

Basic Protocol is a triple

where: x is a list of parameters, – is a precondition, u – process (action), – post condition

)( ux

Forall ms;

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MSC usage

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MSC diagram

alt

loop i=0,i<N

opt

Basic protocols

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alt

loop i=0,i<N

opt

MSC diagram Basic protocols

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alt

loop i=0,i<N

opt

MSC diagram Basic protocols

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alt

loop i=0,i<N

opt

MSC diagram Basic protocols

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Basic Protocols for the MSC diagram

MSC usage

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SDL usage

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SDL in terms of BP

System specification – ENVIRONMENT

Process, functional system component - AGENT

Signals, timers – EVENTS

SDL usage

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system

block 1

e e

n

n

vv II r r o

o

n

n

m

m

e e

nn tt

block 2

block 3

process 2

process 3

process 1

process 4

process 5

Example of structure description of SDL model

Structure linearization

system

process 1(block 1)

process 2(block 1,2)

process 4(block 3)

process 3(block 1,2)

process 5(block 3)

e n v i r o n m e n te n v i r o n m e n t

Linearized structure

SDL usage

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p_1:

state s1;

input i;

p_1_s_1:

task x:=x+y;

p_1_s_2:

task

call prc(x);

p_1_s_3:

nextstate s2;

p_1:

state s2 ...

Control flow label is

agent state expression

state s1;

input i;

task x:=x+y;

task

call prc(x);

nextstate s2;

state s2 ...

s1

i

x := x+y;

call prc(x);

s2

SDL usage Control flow labeling

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task x:=x+y;

p_1_s_2:

task call prc(x);

p_1_s_3:

nextstate s2;

States processing

ProcP(p, p_1 );(ProcP p.state = s1) &get_head(p.queue) = i

ProcP(p, p_1_s_1 );last_signal := i;

SENDER := sender(i);remove_head(p.queue)

ProcP#pp_1:

state s1;

input i;

p_1_s_1:

p_1: state s2; ProcP(p, p_1);(ProcP p.state = s2) &

...

SDL usage

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SDL usage Input and save processing

state s1;

save k;

input i;

...

input j;

...

s1

i jk

ProcP(p, p_1 );(ProcP p.state = s1) &get_head(p.queue) = k

ProcP(p, p_1 );add_tail(p.saved, k);

remove_head(p.queue)

ProcP#p

ProcP(p, p_1 );(ProcP p.state = s1) &

~(get_head(p.queue) = i) &~( … = j) & ~( … = k)

ProcP(p, p_1_s_1 );remove_head(p.queue)

ProcP#pProcP(p, p_1 );

(ProcP p.state = s1) &get_head(p.queue) = i

ProcP(p, p_1_s_1 );last_signal := i;

SENDER := sender(i);remove_head(p.queue);

copy_head(p.queue, p.saved);

ProcP#p

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decision x;

(1): task t1:=1;

(<0): output sig;

enddecision;

...

Decision processing (labeling)

t1 := 1;

x

sig

1 <0

p_1_d_1:

decision x;

(x=1):(task t1:=1;

join p_1_d_2);

(x<0): (output sig;

join p_1_d_2);

enddecision;

p_1_d_2: ...

SDL usage

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Decision processing (BP)

p_1_d_1:

decision x;

(x=1):(task t1:=1;

join p_1_d_2 );

(x<0): (output sig;

join p_1_d_2 );

enddecision;

p_1_d_2: ...

ProcP(p, p_1_d_2 );t1 := 1

ProcP(p, p_1_d_1 );(x = 1)

ProcP#p

ProcP(p, p_1_d_2 );add_tail(T1 P1.queue, sig)

ProcP(p, p_1_d_1 );(x < 0)

ProcP#p

SDL usage

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PROCEDURE fun_name FPAR loc_v;

Local variables declaration

start:

desicion (loc_v)

(1): task u:=1;

(<0): task u:=0;

enddecision;

return;

ENDPROCEDURE;

task t1:=1;

p_7:

task

call fun_name(t1);

p_8:

Procedure calls processingSDL usage

ProcP(p, fun_name );add_head(return_seq, p_8);

loc_v := t1

ProcP(p, p_7 )

ProcP#p

ProcP(p, head(return_seq))

ProcP(p, return )

ProcP#p

ProcP(p, return );[ret values];

[flush loc vars]

return_seq: (ret_control_flow, …, Nil)return_val: (values_set, …, Nil)

stack

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UML usage

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Diagram types and perspectives

Sequence diagrams – analogously to MSC. Architecture diagrams, state chart diagrams –

analogously to SDL system with blocks, processes and state transitions.

Packages and classes structure is linearized (multiplicity, generalization).

UML usage

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Plans

It would be great completely to specify subset of UML notations that are translated to BPSL.

The problem of N instances should be resolved.