The document describes the Gathering pattern, which is an adaptation pattern for multi-agent systems. The Gathering pattern triggers the formation of an initiative by facilitating a casual meeting of agents at a shared "venue," allowing them to begin interacting and coordinating without prior knowledge of each other. Once an initiative is created, it can then evolve into a more established organizational structure through additional adaptation patterns. Adaptation patterns provide attractors that help self-organize agents to form emergent, adaptive architectures.
3. INTRODUCTION
Current software systems keep growing both in
complexity and size
New strategies required to handle this complexity
Self-adaptation: let’s let systems to do routine task
themselves
Many architectural levels to consider
Potential benefits include scalability
Multi-Agent Systems (MAS)
A general problem-solving strategy
Adding organisations to provide further structuring
Adding adaptive support to increase flexibility
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Agreement Technologies: the next step
4. LIFECYCLE OF A SELF-ORGANISING
ARCHITECTURE (I)
The goal is to provide adaptive organisations
With an emphasis on coordination mechanisms
These are created as self-organising architectures
Achieved by creating emergent agreements
Any structure is created by combining controls and
protocols
Controls: enforce or forbid some interaction
Protocols: enable or channel behavior
In a self-organising structure, agents arrange
“semi”-spontaneously in an “elemental” group
This will be known as an initiative
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The first step on an emergent agreement
6. LIFECYCLE OF A SELF-ORGANISING
ARCHITECTURE (III)
Sets of controls & protocols are arranged into
specific patterns
Groups of agents match these patterns, arranging in a
preliminary structure
Initiative: an initial group, which is growing
Organisation: an established group, which provides
specific services (just like any agent)
Agreement: the act which transforms an initiative into an
organisation
These specific patterns are designed to deal with
external adaptation issues
Hence they are called adaptation patterns 6
7. ADAPTATION PATTERNS
Provide an “attractor” trying to “capture” agents into
a developing structure
It either creates or (re)shapes an initiative
They are architectural patterns
In an agent-based, service-oriented architecture
Services “guide” the definition of an organisation
Defines both a structural and behavioural perspective
Two kinds of “special” agents appear
Shifter: an agent which changes
It shifts its own interface and behavior
Changent: an agent of change
It induces changes on others
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8. THE GATHERING PATTERN (I)
A similar structure of “standard” patterns
Just like other adaptation patterns
Has a significant role on a basic “family” of patterns
(“emergent organisation”)
A notion similar to a pattern language
Several different pattern languages can compete /
collaborate for the same set of agents
Gathering: the pattern which triggers the formation
of an initiative
A “casual” meeting of agents starts to evolve to
compose an emergent organisation
Uses a self-organising approach 8
9. THE GATHERING PATTERN (II): STRUCTURE
Name: Gathering
Classification: Creational
Intent: Monitors the space, routing information and
promoting coordination
Context: There is no initiative yet: agents don’t
know each other but should begin interaction
Motivation: To evolve from a simple “set” of agents
to create a service ecosystem
Participants:
Two (or more) agents shifters
A venue (a “gathering place”) the changent 9
10. THE GATHERING PATTERN (III): PROTOCOL
The -calculus specification comprises three
abstractions (processes)
AgentX: behaviour of any agent
First, it wakes and it asks where it is
After event, it identifies and provides a return channel
It receives the name of another agent, they can interact
Repeat that indefinitely
Venue: the gathering place where agents meet
First, it defines itself as a place to register
Once more than one agent has registered, it triggers an event
(of course this can be modified)
The event is used to “broadcast” the name and channel of
every agent to the rest of them 10
Subsystem: serves as the connector in this case
11. CONCLUSIONS
The gathering provides one among many ways to
initiate the communication between agents who
were initially unaware of each other
Once the initiative has been created, it can evolve in
many ways to define an organization
Many other adaptation patterns in charge of this
Surveyor Election, Surveyor, Facade, etc.
Protocols might use a different language
These organisations provide coordination
This is the evolution of agreements, which are also
understood as the evolution of MAS
This approach is still under development
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Adaptive architectures seem already feasible