Seminar: So#ware Engineering of Embedded Systems

Transcription

1 Seminar: So#ware Engineering of Embedded Systems - Quality Assurance of Embedded Systems - Prof. Dr. Sabine Glesner Paula Herber, Nils Jähnig, Lydia Ma7ck, Marcus Mikulcak, Sebas;an Schlesinger Summer term 2014

2 (1) compact course: from 10:00 17:00 in MAR from 10:00 17:00 in MAR appointments with your advisors upon prior arrangement three mee;ngs (at least): 1. preliminary discussion (next week) 2. general concept and structure 3. discussion of the oral presenta;on(at least one week before the compact course) Arrange appointments with your advisiors using ! 2

3 (2) slides due to: to your advisor and berlin.de slides will be uploaded for all par;cipants wriwen presenta;on: a laptop will be provided for all presenta;ons supported formats: PDF, PPT, PPTX this slide set will be uploaded today 3

4 Criteria for Passing the Course talk: min + 10 min discussion wriwen presenta;on: 6 to 10 pages compulsory awendance for all appointments (this includes the whole compact course) 4

5 Seminar - Topics 1. Trace- Based Seman@cs and Refinements à Nils 2. Quality Assurance à Paula, Lydia 3. Correct Model Transforma@ons and MatLab Simulink Seman@cs à Sebas;an 4. Security and Maintainability of Matlab Simulink Models à Marcus 5

6 Trace- Based and Refinements Nils Jähnig berlin.de 6

7 Trace- Based So#ware Engineering and Refinements Specification a b c d Process Algebra e.g. CSP Refinement Implementation a c Programming Language 7

8 Trace- Based So#ware Engineering and Refinements Specification a b c d Process Algebra e.g. CSP Refinement Implementation a c Programming Language 8

9 Trace- Based So#ware Engineering and Refinements Where do the traces for the implementation come from? Trace-Based Semantics 9

10 Trace- Based So#ware Engineering and Refinements Topic 1: Trace-Based Coinductive Operational Semantics for While Infinite Traces 4 different approaches Proofs, that they are equivalent 10

11 Trace- Based So#ware Engineering and Refinements Specification a b c d Process Algebra e.g. CSP Refinement Implementation a c Programming Language 11

12 Trace- Based So#ware Engineering and Refinements Specification a b c d Process Algebra e.g. CSP Refinement Implementation a c Programming Language 12

13 Trace- Based So#ware Engineering and Refinements Refinements are often checked by model checkers è Only finite states Want to have infinite states? è Need a theorem proover 13

14 Trace- Based So#ware Engineering and Refinements Topic 2: A Generic Theorem Prover of CSP Refinement Builds on Isabelle/HOL Allows refinements of infinite state-systems Complete partial orders and Complete metric spaces 14

15 Trace- Based So#ware Engineering and Refinements Program refinement is complicated è Stepwise refinement 15

16 Trace- Based So#ware Engineering and Refinements Topic 3: A fully Verified Executable LTL Model Checker! Not Model Checking! Isabelle/HOL Verify specification Use refinement theories Generate Model Checker in ML 16

17 Quality Assurance for Embedded Systems Paula Herber berlin.de Lydia Ma7ck berlin.de 17

18 Embedded Systems = Control an (analog) technical environment with digital components ð Interac;on with hardware ð Oaen distributed, limited resources and real- ;me constraints ð Have to be efficient and safe During development of embedded systems: Increasing flexibility and op;miza;on Quality assurance: Sta;c techniques: Analysis and formal verifica;on Dynamic techniques: Test and simula;on 18

19 Quality Assurance of ES 1. Does the specifica;on meet the requirements? Is the result of the computa;on in the expected value range? Is signal a always eventually followed by signal b? Is there an overflow? Does signal a reach controller C within 5ms? 2. Does the implementa;on meet the specifica;on? Test case genera;on from specifica;on Compare output behavior Is the system specified correctly? Is the system implemented correctly? 19

20 Formal Goal: Show that a model of the system (specifica;on) sa;sfies given proper;es (requirements) 1. Construct a formal model of the system 2. Formalize desired proper;es 3. Verify requirements Requirements Requirements specification? Formal system model 20

21 HW/SW Co- HW/SW Co- design = integrated design of hardware and soaware components of embedded systems HW/SW Co- verifica@on Has to cope with various Models of Computa/on Combines verifica;on techniques from the hardware and from the soaware world Goal: comprehensive and systema;c verifica;on of hardware, soaware and their interplay 21

22 Major problem in embedded systems verifica;on: scalability Paradigm: divide & conquer Approaches: assume- guarantee, design- by- contract, modular verifica;on, How to decompose the system? How to compose proper;es? 22

23 Topics HW/SW Co- Interval Property Checking Model Checking HW/SW Co- Designs Formalizing Interface Specifica;ons Symbolic Composi;onal Verifica;on Composi;onal Verifica;on of Probabilis;c Systems 23

24 Correct Model and MatLab Simulink Sebas;an Schlesinger berlin.de 24

25 Correct Model General Setting Syntax Meta Model Meta Model Transformation Language Syntactic Model Transformation Syntactic Model Semantics Interpretation Model Interpretation Model 25

26 Preserving Refactorings in Simulink Simulink Graph-based endogenous (inplace) Transformation (Refactoring) 2 Simulink Interpretation by suited Simulink Semantics 1 Result correctness 3 Transformation correctness 26

27 Topics for Correct Model So#ware Engineering and Simulink Topics for this seminar: 1. Opera;onal Simulink Seman;cs Bouissou, O., Chapoutot, A.: An Opera;onal Seman;cs for Simulink s Simula;on Engine, Model Transforma;ons Al- Batran, B. et al.: Seman;c Clone Detec;on for Model- Based Development of Embedded Systems, Verifica;on of Model Transforma;ons Giese, H., Lambers, L.: Towards Automa;c Verifica;on of Behavior Preserva;on for Model Transforma;on via Invariant Checking,

28 Security and Maintainability of Matlab Simulink Models Marcus Mikulcak berlin.de 28

29 Security and Maintainability So#ware Engineering of Matlab Simulink Models Matlab Simulink de facto standard for model- based development embedded systems in automo;ve and aerospace fields Graphical, model- based design early tes;ng due to abstrac;on from implementa;on details Quality and security assurance Numerous methods in tradi;onal soaware engineering S;ll a young research topic in model- based development 29

30 Flow in Java Topic 1: Controlling informa;on flow in Java Informa/on flow control: powerful tool to discover security leaks in soaware, offers: confiden/ality: guarantees for non- leakage of confiden;al data integrity: guarantees, that cri;cal computa;ons cannot be manipulated from the outside These proper;es can be defined and analyzed on program dependence graphs 30

31 Model- based Impact Analysis Topic 2: Change impact analysis in model- based development Impact analysis is concerned with the iden;fica;on of consequences of changes in soaware to ensure quality and maintainability Studied extensively for text- based programming languages, but model- based development poses different, as of yet unsolved challenges 31

32 Slicing Topic 3: Probabilis;c program slicing Program slicing is a common method in soaware change impact analysis: Which parts of a given piece of code influence a certain point of interest, such as a variable or a line Slices can grow very large due to interdependencies between parts of the code Idea: automa;cally extract probabili;es of condi;onal statements, etc., to decrease slice size 32

33 Topic Blocks 1. Trace- Based and Refinements à Nils 2. Quality Assurance à Paula, Lydia 3. Correct Model and MatLab Simulink à Sebas;an 4. Security and Maintainability of Matlab Simulink Models à Marcus 33

34 Topics Overview (1) Block 1: (Trace- Based Seman;cs and Refinements): 1. Trace- Based Coinduc/ve Opera/onal Seman/cs for While 2. A Generic Theorem Prover for CSP Refinement 3. A Fully Verified Executable LTL Model Checker 34

35 Topics Overview (2) Block 2: (Quality Assurance ) HW/SW Co- Verifica/on 1. Interval Property Checking 2. Model Checking HW/SW Co- Designs 3. Formalizing Interface Specifica/ons Composi/onal Verifica/on 1. Symbolic Composi/onal Verifica/on 2. Composi/onal Verifica/on of Probabilis/c Systems 35

36 Topics Overview (3) Block 3: (Correct Model Transforma;ons and Matlab Simulink Seman;cs) 1. Opera/onal Simulink Seman/cs 2. Model Transforma/ons 3. Verifica/on of Model Transforma/on Block 4: (Security and Maintainability of Matlab Simulink Models) 1. Controlling informa/on flow in Java 2. Change impact analysis in model- based development 3. Probabilis/c program slicing 36