1. Blackboard System Applications
Abhishek Shrivastav
Avishek Ghosh
Jagadish M
Sagar Bijwe
Guided By
Dr. Pushpak Bhattacharya
Blackboard System Applications

2. Collaborative Intelligence

3. Blackboard Metaphor
Imagine a group of human specialists seated next to a large blackboard. The specialists are working cooperatively to solve a problem, using the blackboard as the workplace for developing the solution.
Problem solving begins when the problem and initial data are written onto the blackboard. The specialists watch the blackboard, looking for an opportunity to apply their expertise to the developing solution. When a specialist finds sufficient information to make a contribution, she records the contribution on the blackboard, hopefully enabling other specialists to apply their expertise. This process of adding contributions to the blackboard continues until the problem has been solved.

4. Intuitive View Knowledge sources A common place to share knowledge
Control Mechanism

5. Architecture

6. Blackboard Stores Solution Objects Highly Structured
Multiple Hierarchies
Also stores Control Structures

7. Characteristics I think, therefore I am I don't think like you do
If you can draw it, I can use it
What'd you say?
You could look it up
Is anybody there?
It's my turn
Step by step, inch by inch. .

8. Problem Solving Steps Initiation by Knowledge Sources
Control decides what to focus attention on
Knowledge Sources modify solutions
Terminated when either solution is found or no further action is possible

9. A Speech Understanding System
Hearsay II
A Speech Understanding System

10. Sources of Errors
The first source of error is inherent in the speaker and its environment.
Semantic – Conceptualization
Syntactic – Grammar
Lexical - Word choice
Phonemic – Articulation
Other includes, pauses, extraneous sounds or unnessary phrase repeatitions.
The second source of error in the understanding process is intrinsic in the listener.

11. Broad Overview of Hearsay II
Hearsay II has a loosely hierarchial structure.
Hypothesis - A partial interpretation actually constructed.
Many competing hypothesis may occur at the same time.
Credibility – The likelihood of a hypothesis being correct.
The goal of the problem solver is to construct the most credible overall interpretation.
The fundamental operation in the construction are hypothesis generation, hypothesis combination and hypothesis evaluation.

12. Hearsay II Problem Solving Model
Hypothesis generation, combination and evaluation are done by Knowledge Sources.
KSs are condition-action pairs.
KSs communicate through the blackboard.
Role of blackboard:
Repository of hypothesis
Communicates messages from one KS that activate other KSs.
Each hypothesis resides on the blackboard.
The only problem - Combinatorial explosion of the KS invocation that might occur

13. Levels and Knowledge Sources in Hearsay II

14. Hearsay II Architecture
Scheduler executes the highest priority activity in the scheduling queues.
The activity may be a KS condition or a KS action
Blackboard Monitor keeps track of the changes occuring in the blackboard.

15. What Hearsay II gave the world...
A general framework based on which many new world applications have been built.
Hearsay II was the first blackboard system developed.
Accuracy of Hearsay II is 90%

16. Einstein says…
“Hang in there, we’re half-way done!”

17. RADARSAT Canada's first commercial Earth observation satellite
Provides images of Earth for
Ice and ocean monitoring
Arctic surveillance
Detecting ocean oil slicks.
Oceanography
Geology and Agriculture many more

18. Mission Management Office
Translation of request to detailed schedule of activities.
Automated planning and scheduling system .
Many possible scheduling combinations.
Model each of the system elements to check violation
Physical constraint
Policy constraint

19. Hurdles in Development of MMO -PLAN component
No experience of gathering requirement of system.
Planning and Coordination for time segments as small as fractions of second.
Sponsorship by number of participating partners.
140 system constraints.
Changes during the operational life of the system.
No single optimum solution for every combination.
Number of users and user requests
Less amount of time to develop

20. Motivation for Blackboard System
Extensible System
Incremental planning,flexibility
“automable” system
Reduction in the scope of initial development

21. Violation of constraints =>Removal of planned Action
Working of PLAN
KS 1
Constraint 1
Policy Constraints
System Constraints
Planned
Actions
KS2
Constraint 2
KSn
Constraint n
Violation of constraints =>Removal of planned Action

22. Result
“The system works very well”,explained Mohamad Farhat, Software Systems Manager for the mission. “It pulls in requests from around the world, 24 hours a day, and we've never missed a product [delivery].”
“ Each time we bring on a new station,we just add a new set of controllers to interface with the receiving station for the download of image data.”,according to Ken Lord, Project Manager for the operational phase of the mission.

23. What we learned from PLAN
“The most successful applications are never completed they evolve with the enterprises they serve.”
-Blackboard System Provides the Platform.

24. Benefits of blackboard architectures
Flexibility of configuration
Flexible problem solving
Selection of knowledge sources
Multiple problem solvers
Management of multiple levels of abstraction
Opportunistic cooperation

25. Why So Few Blackboard Applications?
Do not scale down to simple problems.
Some systems can be reimplemented without the blackboard structure.
Lack of commercial software
Myth : Blackboard applications are too slow or too hard to develop.
A shortage of application developers with experience building BB applications.

26. Want to develop Blackboard Systems?
Use university research software
GBB
Use in-house expertise
Commercial & open source tools
OpenBBS
GigaSpaces

27. Emerging Directions Parallel Blackboard Architectures
The concurrent execution of knowledge sources (KSs) and control components in shared address space
Distributed Blackboard Architectures
Communication of blackboard data among autonomous blackboard subsystems
Real-time problem solving
Deal with hard real-time constraints imposed by the environment and they must interact with larger systems within which they are embedded

28. Conclusion
More than quarter-century of blackboard-system experience have produced a strong baseline of collaborating-software technologies.
Yet, much more research remains in developing high performance, generic collaborating-software capabilities. Further advances in meeting the collaboration challenges (like representation, interaction, integration & coordination) are needed to enable the next generation of complex collaborative-software applications.

29. References
Lee D. Erman, Frederick Hayes-Roth, Victor R. Lesser, and D. Raj Reddy. The Hearsay-II Speech-Understanding System: Integrating Knowledge to Resolve Uncertainty, Computing Surveys, 12(2): , June 1980.
Daniel D. Corkill. Countdown to Success: Dynamic objects, GBB, and RADARSAT-1, Communications of the ACM, 40(5):48-58, May 1997
Daniel D. Corkill. Blackboard Systems. AI Expert, 6(9):40-47, September,
Dr. John Hunt. JayDee Technology Ltd. Blackboard Architectures. Date: Version 1.0.