L6 - Model Driven Design

Question 1

Modeling

Answer 1

A model represents the reality by recreating system characteristics (replication, simulation) and therefore makes verification possible.

• PRO: easy to understand, simulation of systems, evaluation of different designs, formal methods to test code against models
• CON: difficult underlying processes can lead to unwanted behaviour still possible

Question 2

Design

Answer 2

In model-driven design, models of hardware/software/environment are necessary.

Important are:

• guaranteed performance
• fault tolerance
• verification against model.

Question 3

Analysis

Answer 3

By conducting reachability analysis; model checking; evaluating execution times and testing the fault tolerance; we aim to understand the system.

Question 4

Which type of model is discrete in time; expressed as system of ODEs and discretized with time step T?

Answer 4

Dynamic Models.

Question 5

Finite State Machines (FSM)

Answer 5

Finite State Machines (FSM) are …

• discrete in states (time is implicit)
• expressed as finite set of states
• having transitions which are activated by guard expression transition

Question 6

What is temporal control?

Answer 6

Temporal control determines instants in the real time domain when computations have to be executed.

Question 7

Synchronous Reactive Systems

Answer 7

Synchronous Reactive Systems produce outputs synchronously to changes of inputs.

Question 8

Event Triggered Control (Reactive Systems)

Answer 8

Event Triggered Control (Reactive Systems) produce output for each input event. Emphasis is placed on safety and determinism but execution of events can overlap.

Question 9

Principles Of Composability

Answer 9

• Independent Development Of Component: platform independent model (PIM) complies with Linking Interface (LIF).
• Stability Of Prior Service: services validated in isolation.
• Non-Interfering Interactions: communication of subgroups should not interfere with each other.
• Preservation Of Component Abstraction: redundancy in order to detect faulty components.

Question 10

Dataflow (Model Of Computation)

Answer 10

Execution depends on data and has to wait until data is ready. Especially Discrete Dynamics (Labview; Simulink)

Question 11

Time-Triggered Execution (Model Of Computation)

Answer 11

Execution is planned for each instant in time. Especially real time control (Giotto; FTOS)

Question 12

Component Interaction (Model Of Computation)

Answer 12

Composition of data and query driven execution. Especially web servers.

Question 13

Process Networks (Model Of Computation)

Answer 13

Processes communicate through channels that message in a queue (asynchronous). Especially in distributed systems.

Question 14

Rendezvous (Model Of Computation)

Answer 14

Processes communicate via synchronous messages (wait until both sender and receiver is ready).

Ex.: CSP, Ada

Question 15

What is a Deterministic System?

Answer 15

In a deterministic system the worst case response time is predictable. Sufficient for RTS.

Question 16

ESTEREL

Answer 16

• synchronous language that was developed to program reactive systems
• Esterel programs are divided into modules that can be executed sequentially, parallel or repeadtedly where the communication works via a broadcast mechanism.

Question 17

MATLAB/Simulink is a ___________________ environment for continuous and discrete dynamics. What is its functionality?

Answer 17

Synchronous block diagram.

Matlab enables simulation, controller design, prototyping; code generation, verification, validation and Hardware-/Software-In-The-Loop.