1. Plan of the talk Basic Specification blocks
Specification of Data Structures
Specification of Simple Systems
Specification of Structured Systems
Development methods for main “Problem Frames” using

2. Problem Frames (M. Jackson, Addison-Wesley 2001)
“It is important to focus directly on a problem, not just going straight to the design of a solution.
The computer and its software are the solution; the problem is in the world outside the computer.”
“A problem frame defines the shape of a problem by capturing the characteristics and interconnections of the parts of the world it is concerned with, and the concerns and difficulties that are likely to arise.”
“But most realistic problems are too big and complex to handle in two levels like this.
Another level is needed: structuring the problem as a collection of interacting subproblems.”

3. Solving Problem Frames with our Formally-Grounded Specifications
Basic problem frames
Transformation Frame
Control System Frame
Information System Frame (see paper)
Work-pieces (still to be done)
Structured problems (still to be done) To
show that we can tackle real problems
derive specialized methods to handle more effectively the various problems
Future
New/modern problem frames (e.g., web applications, business support) as basic or structured problems

4. Schema of a problem frame
Design
Requiremnts
Machine
Domain
What your Machine
has to do
The result of
your creative act
Existing
It is not your
responsibility
Discovered interacting
with the client

5. Transformation frame
Domain
Requirements
Design

6. Transformation frame: GREP
Input
Output
IO relation
Machine
Text File
Regular
Expression
……...
……...
Occurrence
list

7. Transformation frame: Specification
DATA STRUCTURE SPECIFICATION
Requirements
Design
Domain

8. Domain Specification Data Structure Specification Data Structure
Input
Output
IO relation
Machine
Data Structure
Specification
Data Structure
Specification

9. Requirements Specification
Specification of a data structure having Input and Output as parts, and a predicate
IO: input X output
Input
Machine
IO relation
Output

10. Design Specification
Specification of a data structure having Input and Output as parts,
and a partial operation
Tran: input -> output
Input
IO relation
Machine
Output

11. Control System Frame
Domain
Design
Requirements

12. Control System Frame: Lift
Controlled Domain
Controller
Main Part
Desired Behaviour
Domain Reports
User Orders
User
Sensors
Orders
requests
Reports
Cabin position
Motor status
Door status
Lift Plant
Open/close door
Move up/down/stop
If a person asks to go to floor f, then eventually the cabin will be at floor f with the door open.
………….
Enter/leaving
Go to floor f
Lift controller
Persons to be
transported

13. Control System Frame: Specification
STRUCTURED SYSTEM SPECIFICATION
Domain
Design
Main Part
Sensors
Controller
Orders
Requirements
Domain Reports
User Orders
Controller
Desired Behaviour
User
Requests
User
Controller
Reports
Controlled Domain
ADDITIONAL
PROPERTIES on

14. Domain Specification Dynamic System Specifications Elementary
Sensors
Dynamic
System
Specifications
Main Part
Controller
Orders
Elementary
Interactions
Domain Reports
User Orders
Special form of
their properties
User
Requests
User
Controller
Reports

15. Requirement: Specification
Controlled Domain
Controller
Main Part
Domain Reports
User Orders
User
Sensors
Orders
Requests
Reports
PROPERTIES on
of a special form
Post-conditions for User Requests
Pre-conditions and vitality for Controller Reports
Properties on State Observers of Main Part

16. The End