lecture 4 component behavioral modeling with remes advanced component-based software engineering

Lecture 4

Component Behavioral Modeling

with REMES

Advanced Component-Based Software Engineering

Agenda

Background and Motivation REMES Connecting REMES and ProCom REMES Editor

Lab2


Embedded systems “Computer that does not look like computer” Part of a larger system or machine

Typical requirements Low cost Constantly react to changes in the environment Dependability Compute certain results in real-time without delay Limited available resources Manage the growing complexity of software

Need for solutions that Alleviate software complexity Ensure predictable system behavior

Background and Motivation


C2

{RC2}

C3

{RC3}

Cn

{RCn}

{RB} > {RC1}

C1

{RC1}B{RB

RepositoryRepository



Challenge construct component model for ES design enriched with

behavioral information support predictable system development and as such

guarantee absence or presence of certain properties prediction methods should be available already at early design

stage bottom-up resource analysis can guide the selection of components top-down resource analysis could help in correct decomposition of

system’s specification



REMES behavioural language


Resource Class Characteristics

A(memory)

discrete c´=0 or c’=inf referable

B(CPU, bandwidth)

discrete c’=0 or c´=inf non-referable

C(CPU, energy)

continuous c´=n, n in Z - {-inf,+inf} non-referable

Resource consumption- annotated with c;

accumulated resource usage up to some time point c’ - rate of consumption over time Classification of resources:

discrete or continuous nature referable or non-referable

Classification of resources


REMES – REsource Model for Embedded Systems

Behavioral model intended to describe the resource-wise behavior of interacting embedded components

Behavior of a component is a mode

Modes atomic composite


REMES - modes Mode M (SM, V, In, Out, E, RC, Inv, CC)

Control points In: (Init point, Entry point), Out: (Write point, Exit point) Variables (V) (boolean, natural, integer, array, clock, history variables) Actions over edges (E)

discrete A (guard, body) delay/timed

Constraints set of invariants (Inv) set of res. diff equations (RC)

Conditional connectors (CC) Nested submodes (SM)

Entry Point

Init Point

C

M

submode1 submode2

submode3

Exit Point

Write Point

(guard, body)

Inv1RC1

C

Control

Init

Entry

Exit

login=userdata

cpu’=2

t<=30,

Credentials

Air_conditioning

Example1- internal behaviour of Control component in REMES

logged==true

logged==false

cpu’=10eng’=2

mem+=30, t:=0

Initializationresource mem:TA; resource cpu:TC; resource eng:TC; t:clock

turnoff==tru

e

Analysing REMES based ES

REMES modes have access to R1,…, Rn

Goal analyze various scenarios of system’s resource usage

Analysis model for REMES

rtot total accumulated resource consumption for R1,…, Rn

r1,…, rn accumulated consumption of R1,…, Rn

w1,…, wn relative importance of r1,…, rn

nndeftot rwrwrwr 2211


12


Translating REMES into Priced timed automata or Multi PTA TA + costs on locations and edges

REMES atomic submode PTA location(s) REMES discrete edge PTA edge REMES discrete step PTA transition REMES conditional connectors are removed

Automated translation Types of analysis

Feasibility Optimal/ worst-case resource consumption Trade-off analysis

• PTA waits in location Start for system startup

• Init, Entry, Write and Exit locations created

• Transformation of Submode2

• Internal execution rounds - PTA edge connecting locations Write and Submode1

• Synchronization with other components


Model Checker(Uppaal Cora)

PTA / MPTA

resource-aware property

error trace

yes

Assumptions from hardware abstraction:

Memory budget, Bandwidth, Cost model

vEF ntcos



ProCom component REMES model of component behavior

Attribute Framework Managing and integrating properties

Each ProCom component has an attribute with a complex value: Reference to a REMES model file Reference to a mapping file between ProCom and REMES interfaces



ProSave level trigger port REMES interface boolean variable data port REMES interface data variable

ProSys level input message port REMES read boolean variable

and REMES read data variable of the same type as the port type

output message port REMES write boolean variable and REMES write data variable

Connecting ProCom and REMES


Example2- Temperature control system

core is heated at some given rate

core temperature should be maintained

between a minimum and a maximum

when max temp. is reached, designed to be cooled down by inserting one of two existing rods , which cool at different rates R1 or R2

a rod is available again after T time units


Model of the architecture and behaviour System modeled with 3 ProSave components Each component has a behavior depicted by a REMES mode Assume memory and cpu usage Formal analysis

ProCom + REMES PTA



Example2- Temperature control system – Analysis in Uppaal

Just for illustration!

QUESTIONS ???


REMES tool-chain


The REMES tool-chain consists of

REMES model editor REMES simulator to test timing and resource

behavior prior to formal analysis Automated transformation from REMES to PTA

for formal analysis and UppaalLite editor

Integrated in PRIDE

REMES tool-chain


REMES tool-chain

, CBSE graduate course

REMES editor


, CBSE graduate course

REMES language elements

Composite mode Compartments for declaration variables, resources, constants



Submodes Invariant – time is allowed to pass until invariant is violated Non-lazy – does not contain any.invariant, Time is allowed to pass in a non-lazy mode until at

least one of the guards of the outgoing discrete actions evaluates to true Urgent – time is not allowed to pass (invariant is false)



Input and output Init-, entry-, exit-, write – points (local exit points not presented here)



Control flow

Edges with guards and actions Conditional connectors


Introduction to Lab2


Objectives Learn how to model behaviors of component-based

embedded systems

Model internal behavior of components Think about modes, actions, resources, invariants etc. Get familiar with the REMES editor


Expected Output

Same system as for Lab1 Archive files only (no folder) named ”Lab2_X.zip” where

X is student name1 report explaining your design choices

The Project folder for your system

Submission to [email protected]

Individual work And nothing else!

Do not copy solutions from others !


Deadline

Thursday 21 February 2014 23:59 (FIRM Deadline!)

If you submit your work late, you fail one submission opportunity

Remember Lab2 needs to be aproved for passing the course

The assignment

In 2 exercices Modelling behavior of simple Touch-Lamp system Modeling behavior of an abstracted version of a

Baking Conveyor System


Exercise 1- Touch Lamp System

Lamp has two modes of light operation

• Dim – 1 touch

• Bright – 2 successive touches within 15 sec


Exercise 2- Industrial Baking Conveyor System

Main parts• Oven• Conveyor Belt• Orchestrator


Usage Scenario

Orchestrator

OvenConveyor Belt

Oven monitors the temperature and humidity and determines 1. if the heat should be increased or decreased and 2. displays the status of the cookies

Carries the cookies from point A to point B in passing by the oven

Ensure that the conveyor belt and the oven are working together


Exercise 1 and 2- What do you need to do?

To model the behaviour of the system components Lamp component for Exercise 1 Orchestrator, Oven and Conveyor Belt component for

Exercise 2 Tips

Start by understanding REMES think about different types of modes that exist in REMES

Use pen and paper before using REMES editor Once you are sure of your solution. Model it in

the REMES editor


Questions ???Advanced Component-Based Software Engineering

lecture 4 component behavioral modeling with remes advanced component-based software engineering

Documents

software complexity

remes resource model

motivation remes

point guard

time point c rate

component behavioral

bandwidth discrete c

memory discrete c