Introduction

Question 1

Definition: Embedded Systems

Answer 1

“Embedded systems are information processing systems embedded into a larger product” - Peter Marwedel

Question 2

Definition: Cyber-Physical Systems

Answer 2

“Cy-Phy Systems are integrations of computation with physical processes” - Edward Lee

Cyberphysical system (CPS) = Embedded System + physical environment

Question 3

Definition: Ubiquitous Computing

Answer 3

Information anytime, anywhere

Question 4

Characteristics: Dependability (5)

Answer 4

CPS & ES must be dependable:

• Reliability R(t) = Probability of a system working correctly (works at t=0)
• Maintainability M(d) = Probabilty system works d time units after error occured
• Availability A(t) = Probabily of system working at time t
• Saftey = no harm causing
• Security = Confidential and authentic communication

Question 5

Characteristics: Efficiency (5)

Answer 5

CPS & ES must be efficient:

• code-size efficient
• run-time efficient
• weight efficient
• cost efficient
• energy efficient

Question 6

Characteristics: Real-time constraints (hard, soft)

Answer 6

CPS & ES must meet Real-time constraints:

• reaction of ES in time interval dictated by environment
• “a real time constraint is called hard, if not meeting the constraint could result in a catastrophe.” (Kopetz 1997.)
• all other time constraints are called soft

Question 7

Characteristics: Reactive System

Answer 7

• “A reactive system is one which is in continual interaction with its environment and executes at a pace determined by that environment”.

Question 8

Characteristics: Hybrid System

Answer 8

“System with analog and digital parts”

Question 9

Characteristics: Dedicated Systems

Answer 9

• dedicated to a certain application (minimize resources and maximize robustness)

Question 10

What are the major characteristics of CPS & ES and what alternative definition follows for an ES?

Answer 10

• Dependability
• Efficiency
• Real-time constraints
• System Type (hybrid, dedicated, reactive)
• Security

Not every CPS & ES has ALL of the above characteristics :
Def. “Information processing systems having most of the above characteristics are called embedded systems”.

Question 11

Challenges in Embedded System Design? (hardware/software)

Answer 11

• Implementation in hardware: lack of flexibility, expensive mask cost for specialized integrated circuits
• Implementation in software: knowledge of many areas must be available (not only software),testing and validation of specifications
• Software Complexity: code size and development cost (i.e. >70% for development cost of car electronics)

Question 12

Hypothetical Design flow in Embedded Systems?

Answer 12

1. Application Knowledge
2. Specification
3. ES-Hardware
4. System Software

(reoccuring) :
5. Evaluation & Validation (energy, cost, performance)
6. Application mapping
7. Optimization

8. Test