Download - Lecture 23 – April 11, 2002
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Lecture 23 – April 11, 2002
Semester end questions
More about Bond agents
Models and languages supporting concurrency
Petri Nets
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Final Exam and Project
The final exam will be Thursday April 25,
7:00 – 9:00 PM in this class room.
The class project is due on Monday April 22 at 9 AM. See http://www.cs.ucf.edu/~dcm/Spring02Class/Projects.html for a description of the format and contents of project.
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Office Hours during the last weeks
I will be out of town Sunday April 14 till Saturday, April 20.
I will be available on Tuesday, April 24, 3 – 6 PMThursday, April 15, 4- 7 PM
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Final Exam
Open book
Comprehensive
Two hours
4-6 problems
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Final project presentations
Tuessday – April 16:7:00 – 7:20 David Aihe7:20 – 7:40 Kiran Anna 7:40 - 8:00 Temitope Alo8:00 - 8:20 Xin Bai
Thursday – April 187:00 – 7:20 Wafa Elgarath7:20 – 7:40 Shan Natarajan7:40 – 8:00 Sudipta Rashit8:00 - 8:20 Vivek Singh
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Final project presentations
Friday – April 19 CS 232 (Seminar Room)9:00 – 9:45 John Anthony9:45 – 10:30 Brian Hill10:30 – 11:15 Mathew Lowerey11:15 – 12:00 Aniruddha Tumalla
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Agent Factory
Action SchedulerSemantic Engine
S2S1
S3
Model
StrategyData Base
Resident
TupleSpace
BlueprintRepositoryBlueprint
Repository
WebServer
Local Host
Multiplane Agent
Agent
Agent Control Structure
NETWORK
ACS
ACS
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AgentFactory
InternalRepresentation of
an AgentState Machines:-states
-transitions
Strategies
Blueprint of anAgent
Model of theWorld
Agenda
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Agent Factory
Action SchedulerSemantic Engine
S2S1
Model
Resident
Modified Multiplane Agent
Modified AgentControl Structure
ACS
ACS
Agent Factory
Action SchedulerSemantic Engine
S2S1
S3
Model
Resident
Original Multiplane Agent
Original AgentControl Structure
ACS
ACS
OriginalBlueprint
SurgicalBlueprint
ModifiedBlueprint
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Agent Factory
S2S1
Model
Resident
Multiplane Agent
ACS
ACS
Agent Factory
S2S1
S3
Model
Resident
Multiplane Agent
Agent Control Structure
ACS
ACS
Beneficiary
S3
shadowof model
(i) migrate-agent (xi) success (xii) control-agent
Blueprint
(iv) migrate-agent
(x) start-agent
Agent Control Structure
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Agent transformations
Trimming.
Splitting.
Joining.
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read()take()write()
Access contolCheckpointing
Tspace server
tuples
read()waittoread()
scan()
take()
match()
consumingscan()
write()
count()
or()
index()
and()
waittotake()
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Tuplespace
CoordinatorAgent
1 4
Notify Completion
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Software Installation Workload DataGeneration
HTTP RequestGeneration
MeasurementData Analysis
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
MonitoringAgent
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M; Petri NetModel ofSystem S
Modeling
Translation
MP; ModelProperties
SP; SystemProperties
SystemAnalysis
StaticAnalysis of
the NetModel
DynamicAnalysis of
the NetModel
Remapping
(a)
Translation
MP; ModelProperties
DynamicAnalysis of
the Net
StaticAnalysis of
the Net
(b)
S; Real-lifeSystem
M; Petri NetDescription of
a SoftwareSystem S
S; SoftwareSystem
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Place/Transition nets
In 1962 Carl Adam Petri introduced a family of graphs, called Place-Transition, P/T nets to model dynamic behavior of systems. P/T nets, are bipartite populated with tokens, that flow through the graph. A bipartite graph is one with two classes of nodes; arcs always connect a node in one class with one or more nodes in the other class. In the case of P/T nets the two classes of nodes are places and transitions; arcs connect one place with one or more transitions or a transition with one or more places.
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P/T nets
Enabling and firing of a transitionWeight of flow relations (arcs).Marked P/T netPreset and postset of a transition/place.Modeling choice and concurrency.Confusion – symmetric and asymmetricMarked graph –concurrency but no choice State graph graph – choice but no concurrencyInhibitor arcs – modeling priority
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2 1
3
p1 p2
p3
(a) (b) (c)
t1
(d) (e) (f)
2 1
3
t4
(g)(h)
(i)
p4
t3
n
nn
n(j)
2 1
3
p1 p1
p1p1
p1
p1
p1
p1
p2 p2
p2p2
p2
p2
p2
p3 p3
p3
p3
p2 p3
p3
p3
t1
t1
t1t1
t1
t1
t1 t1t1
p1
p4
p4
p4
t2t2
t2
t2
t2
t2 t2
p4
t3
t3
t3
t3
t4
t4
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P/T nets
Marking state
Finite/infinite capacity nets
Strict/weak firing rules
Extended P/T nets – P/T nets with inhibitor arcs.
Modeling exclusion.
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Properties on P/T nets
Marking independent properties of P/T nets – structural properties
Marking dependent properties of P/T nets.
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State machines
Finite state machines can be modeled by a subclass of L-labeled P/T nets called state machines (SM) with the property that
In a SM each transition has exactly one incoming and one outgoing arc or
This topological constraint limits the expressiveness of a state machine, no concurrency is possible.
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Marked graphsIn a marked graph each place has only one incoming and one outgoing arc thus marked graphs do no not allow modeling of choice.
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Confusion; free-choice and extended free-choice P/T nets.
When choice and concurrency are mixed, we end up with a situation called confusion. Symmetric confusion means that two or more transitions are concurrent and, in the same time, they are in conflict with another one.In an extended free-choice net if two transition share an input place they must share all places in their presets. In an asymmetric choice net two transitions may share only a subset of their input places.
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MarkedGraphs
Free Choice
Asymmetric Choice
Place Transition Nets
StateMachines
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Marking dependent properties
Liveness
Boundedness
Safety
Refersibility
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Firing sequence
Firing sequence
Rechability analysis
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Q
N
N
R
(a) (b)
(d)(c)
p1 p1
p1 p1
p2 p2
p2 p2p3 p3
t1 t1
t1
t1
t2 t2
t2
t2
t3