1. What is a timed automaton primarily used for?
(A) Modeling functional correctness
(B) Modeling time-dependent system behavior
(C) Database transaction control
(D) Compiler optimization
2. Who introduced the concept of timed automata?
(A) Leslie Lamport
(B) Alur and Dill
(C) Tony Hoare
(D) Edsger Dijkstra
3. Which component is added to finite automata in timed automata?
(A) Threads
(B) Variables
(C) Clocks
(D) Queues
4. What do clocks in timed automata measure?
(A) Memory usage
(B) Execution cost
(C) CPU frequency
(D) Elapsed time
5. Which of the following is a key characteristic of clocks in timed automata?
(A) Continuous real-valued time
(B) Boolean values
(C) Discrete values only
(D) Random increments
6. What is a clock constraint in timed automata?
(A) A scheduling rule
(B) A memory limit
(C) A condition on clock values
(D) A process priority
7. Which symbol is commonly used in clock constraints?
(A) =
(B) ∧
(C) ≤
(D) →
8. What happens to clocks during a reset?
(A) They stop progressing
(B) They are set to zero
(C) They are assigned infinity
(D) They double in value
9. Which element specifies allowable clock values in a state?
(A) Guard
(B) Transition
(C) Invariant
(D) Label
10. Guards in timed automata are associated with:
(A) Transitions
(B) Clocks only
(C) States
(D) Events
11. What does an invariant violation cause?
(A) Deadlock
(B) Immediate transition
(C) State exit
(D) Time stop
12. Which type of time progression is allowed in timed automata?
(A) Discrete only
(B) Both discrete and continuous
(C) Continuous only
(D) Random
13. Which formalism is timed automata an extension of?
(A) Petri nets
(B) Pushdown automata
(C) Turing machines
(D) Finite automata
14. What is a location in timed automata equivalent to?
(A) State
(B) Thread
(C) Process
(D) Clock
15. Which operation is NOT allowed on clocks?
(A) Reset
(B) Comparison
(C) Progress with time
(D) Addition of two clocks
16. What type of system is best modeled using timed automata?
(A) Batch processing systems
(B) Text editors
(C) File systems
(D) Real-time embedded systems
17. Which property can be verified using timed automata?
(A) Memory fragmentation
(B) Deadlock freedom with time constraints
(C) Code readability
(D) Disk throughput
18. What does reachability analysis determine?
(A) Reachable states under timing constraints
(B) Maximum clock value
(C) CPU usage
(D) Scheduling order
19. Which tool is commonly used for timed automata verification?
(A) UPPAAL
(B) NS-3
(C) MATLAB
(D) Wireshark
20. Timed automata are mainly used in which verification technique?
(A) Simulation only
(B) Testing only
(C) Model checking
(D) Compilation
21. What does a transition in timed automata represent?
(A) State change possibly with clock reset
(B) Time delay only
(C) Clock creation
(D) Process termination
22. Which type of clock constraint is allowed?
(A) x + y ≤ 5
(B) x − y ≥ 3
(C) x ≤ 5
(D) x × y < 10
23. What is a timed trace?
(A) Sequence of states with time stamps
(B) Sequence of instructions
(C) Memory dump
(D) Event log without time
24. Which feature makes timed automata suitable for real-time analysis?
(A) Nondeterminism
(B) Clock synchronization
(C) High-level abstraction
(D) Explicit modeling of time
25. Which of the following is NOT a component of timed automata?
(A) Stack
(B) Clocks
(C) Invariants
(D) Locations
26. What does nondeterminism allow in timed automata?
(A) Infinite clocks
(B) Random clock resets
(C) Multiple possible transitions
(D) Undefined states
27. Which condition must hold for a transition to fire?
(A) Invariant must be false
(B) Guard must be satisfied
(C) Clock must stop
(D) Time must reset
28. Which real-time constraint can be modeled using invariants?
(A) Minimum delay
(B) Maximum allowed time in a state
(C) Event priority
(D) Task dependency
29. Timed automata clocks progress when:
(A) System is in a location
(B) System is idle
(C) Transition occurs
(D) Reset happens
30. Which logic is often used with timed automata?
(A) Propositional logic
(B) Timed Computation Tree Logic
(C) Linear Temporal Logic
(D) Predicate logic
31. What is the main limitation of timed automata?
(A) Too expressive
(B) No real-time support
(C) Lack of tools
(D) State space explosion
32. Which approach helps reduce state explosion?
(A) Overclocking
(B) Manual inspection
(C) Random testing
(D) Abstraction
33. Which system behavior is captured by clock invariants?
(A) Ordering of events
(B) Memory usage
(C) Maximum time delay
(D) Task priority
34. What does a location invariant restrict?
(A) Transitions only
(B) Guard evaluation
(C) Reset behavior
(D) Clock progression in a state
35. Which is a typical application of timed automata?
(A) Web page design
(B) Network protocol verification
(C) Image processing
(D) Game graphics
36. Which type of clock is used in timed automata?
(A) Discrete clock
(B) Logical clock
(C) System clock
(D) Real-valued clock
37. What happens if time cannot progress due to invariants?
(A) Normal execution
(B) Transition ignored
(C) Deadlock
(D) Clock reset
38. Which property ensures an event happens before a deadline?
(A) Liveness
(B) Safety
(C) Timeliness
(D) Fairness
39. Which modeling aspect differentiates timed automata from FSMs?
(A) Inputs
(B) Outputs
(C) Time constraints
(D) Alphabet
40. What is zone-based analysis used for?
(A) Memory allocation
(B) Code optimization
(C) Representing clock constraints efficiently
(D) Event scheduling
41. Which of the following is a verification question in timed automata?
(A) Is a deadline always met?
(B) Is memory allocated?
(C) Is code optimized?
(D) Is file closed?
42. Timed automata transitions are triggered by:
(A) Time only
(B) Memory access
(C) Events and time conditions
(D) CPU interrupts only
43. What does synchronisation allow in timed automata networks?
(A) Shared memory
(B) Coordinated transitions
(C) Clock deletion
(D) Priority inversion
44. Which system type often uses networks of timed automata?
(A) Single-thread programs
(B) Distributed real-time systems
(C) Text processing systems
(D) Standalone utilities
45. What is a run in timed automata?
(A) Compilation phase
(B) Testing script
(C) Debugging process
(D) Execution sequence with timing