1. Blackboard Architecture
Group5_ SE0304:
1. Nguyễn Thúy Ngân
2. Nguyễn Xuân Hiếu
3. Đỗ Tiến Hưng
Sortware Srchitecture Design

2. Table of contents
• Introduction Blackboard Architecture Style
• Applicable
• Benefit of Blackboard architecture
• Drawbacks of Blackboard architecture

3. 1. Introduction to Blackboard
Architecture
• Basic idea
• Forward Reasoning or Backward Reasoning
• Architecture
• Class diagram
• Sequence diagram

4. 1.1 Basic idea
• The idea of blackboard architecture is similar to the
classroom blackboard setting used in solving problems.
• It is a data-directed and a partially data-driven
architecture.
• The whole system is decomposed into two major
partitions:
– blackboard, used to store data (hypotheses and facts)
– knowledge sources, where the domain-specific knowledge is
stored.
• There may be a third partition called the controller , used
to initiate the blackboard and knowledge sources, takes a
bootstrap role and overall supervision control.

5. 1.1 Basic idea
• Specific knowledge sources collaborate together to
solve a complex problem
• Knowledge sources don’t need to interact with each
other, only need to interact and respond to the
blackboard sub-system.
• Each source only works on a specific aspect of the
problem

6. 1.2 Forward Reasoning
& Backward Reasoning
• The forward reasoning starts with the initial state of
data and proceeds towards a goal.
• If the goal is not given, the reasoning will come to a
point where no more new facts can be derived that
indicated that is the best result we can get.
• The backward reasoning works in the opposite
direction than the forward reasoning.

7. 1.3 Architecture

8. 1.4 Class diagram

9. 1.5 Sequence diagram

10. 2. Applicable
• Weather broadcast systems.
• Pattern recognition
• Authentication in information security.
• Etc.

11. 2. Applicable
_A Web Application_
• the development of a web application in the
domain of movie chains

12. 2. Applicable
_A Web Application_

13. 2. Applicable
_A Web Application_
• Structure in
Blackboard
Architecture has
three partition
Blackboard
Knowledge sources
Controller

14. 2. Applicable
_A Web Application_

15. 2. Applicable
_A Web Application_
Knowledge sources
• Iknowledgesource defines an interface for all the KS.
• Movie Information (InformacionpeliculasKS)
• Anonymous reservations (ReservacionAnonimaKS
• Member reservations (ReservacionMiembrosKS)
• Show Movie Guide (PresentarFuncionesKS)
• Close reservations (CierreReservacionesKS)
• Close functions (CierreFuncionesKS)

16. 2. Applicable
_A Web Application_
Blackboard
• The Blackboard holds all the data concerning the
weekly and daily movie guide; it also provides special
methods for supporting the updating process carried
out by knowledge sources. It is a Singleton, therefore
only one instance of the movie guide exists.

17. 2. Applicable
_A Web Application_
Control
• The control extends the Thread java class and runs a
separate thread monitoring constantly the Blackboard’s
state. It contains a list of registered knowledge sources
for their automatic activa-tion (if that is the case). In
addition, it allows the communication among the jsp
pages and the manual knowledge sources.

18. 2. Applicable
_A Web Application_

19. 3. Benefit of Blackboard architecture
• Scalability: easy to add new knowledge source
or update existing knowledge source.
• Concurrency: all knowledge sources can work
in parallel since they are very independent of
each other.
• Supports experimentation for hypotheses.
• Reusability of knowledge source agents.

20. 4. Drawbacks of Blackboard architecture
• Tight dependency between the blackboard and
knowledge source
• Difficult to make a decision when to terminate
reasoning
• Synchronization of multiple agents is an issue.
• Debugging and testing of the system is a
challenge.

21. Thanks for
listening!