[AAMAS09] From DSP to MAS to… Continuing the trends

invited talk by Michael N. Huhns

Interesting metaphores for differente technologies

  • DPS: decomposition
  • DAI: coordination
  • MAS: interaction
  • SOC: encapsulated functionality with a public interface

Nowadays, some social challenges in economy, energy, environment, transportation, telecommunication are the great problems of our age. And they’re massive, distributed, many-faced, with a large number of dependant componentes, controlled action is needed, but centralised control infeasible. SO agents are the tool (I guess) for addressing these problems.

Characteristics of agent paradigm:

  • large-scale multiagent participation
  • spatially distributed
  • temporally extended
  • uneven progress
  • possibly cooperative
  • design domain isomorphic to execution domain
  • constrained: it can’t pave everything and no semantic mismatches
  • solution is not centralised, bat it occurs at the edge

Example: individualised transportation.
routes of rails and traffic are designed centralised by engineers, instead of be done in real.time by passengers. Speeds limits are set centrally andd fixed. Traffic lights are barely reactive to local traffic, when it can be auctioned in each intersection…. and meny other examples.

Example: individualised healthcare
The systems are designed for hospitals and caregivers, but not for patientes

Example: grocewry shopper
supermarket chains use IT to set prices, but they’re no systems for shopper to find fair prices. Even shoppers could use RFID tagged items in their own profit.

Example: governance
a citizen has a vote that is given to a representative to be used for N issues.

Example: energy
Europen S-TEN project is using semantic web tech to make each componente of hte energy grid to report on its status intelligently. The result is a finer grained status to human operators of the grid

Example: taxation
determine the fair share of every one. In general, people doesn’t mind to pay what is fair, but it is diffucult to determine in the case of ‘commons’.

…and a very interesting example in logistics that I’ve prefered to listen to).

All this is compared with the example of Columbia university: they put the building rounded completely by grass. And after one year they just paved the worn paths made by people. This is the same criteria in all the previous examples: let the agents to interact and to create or re-create the model by themselves.

Consensus …
Consensus ontology: a first step towards agreement spaces. Take a look at this.
Consensus behaviour: select a plan/sequence of actions from the behaviour of the rest (emergence?). So you can find the best algorithm to do something

Hyperscale sw development: consensus provides a different way for developing sw: encourage lots of people to contribute to software systems and they use all of their constributions. The problem is how all these contributions can be combined.

Idealised SOC: given the requirements of an applitacion: (i find a sert of services that cover the requirements nad (ii) workflow
but it is still unused. They’re very similar to agents, but agents have some benefits: autonomy, they’re active components, are complex (n-party interactions)…The problem: flexibility and reliability. HOw to fix it?
decrease autonomy increases predictibility n(this is why SOA is more used that agents)
removing semantic inconsistences too
transaction concepts can ensure ACID resutls
agents can recover states and maintain their progress toward overall goals at run-time.

Well, and it ends with a great sentence that I’ll add here. I’ve written this post complelety on-line, so I’ll need to review it and make some (minor) changes.

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[AAMAS09] Multi-Agent Learning II. Emergent Behaviour II

Well, well, well, finally I’m in a room

Stigmergic Landmark Foraging
Nyree Lemmens, Karl Tuyls

Late

Integrating Organizational Control into Multi-Agent Learning
Chongjie Zhang, Shereif Abdallah, Victor Lesser

Problems of distributed learning

  1. 1
  2. 2
  3. 3

Basic idea: organisational-based supervision framework. It’s a multilevel structure (recursive?) Lowest level network agents are ‘workers’. Each leaning agent reposrt its abstract state to its inmediate supervisor and them use rules a suggestions to transmit its supervisory informatio to its subordinates. Rules are set of forbidden actions and suggestions are actions with a degree in [-1,1], Rules are hard constraints and sugg are soft constraints that represent preferences.

The problem they’ve used to test this model is DTAP (distributed task allocation problem). Using a 27×27 agent grid… only!!!, too small!! I can manage several millions of agents to do the same :-( The results: interesting, but I don’t
understand all this stuff to be used in a small network as this: two supervision levels for such a group of agents.

It scales, but adding more supervision levels that may affect to the performance. I don’t like it. You’ll need a lot of layers for a really big network. Furthermore, in the experiments they’ve used a grid instead of a network and this is not ‘elegant’.

Multiagent Learning in Large Anonymous Games
Ian Kash, Eric Friedman, Joseph Halpern

We need to learn quickly, with minimal information and despite of noise. And to test their method they’re using games, but instead of being game theoretic games, they’re continuous, anonymous and designed games. He explains the method with a simple game but at the end it’s similar to game theory… I hate utility functions for agents. The behaviour can’t be reduced to a number or a function. Agents are more complex that that. We are more complex than that.

A simple algorithm to adapt the agent’s behaviour to the rest, so the dynamic converge despite of having agents making mistakes (so they’re introducing noise) in their decisions. As the number of agents increases, the system is more stable and converges faster… they’ve tried with 100 agents (again, too small for me). This results allows to tolerate strange behaviours.

Learning of Coordination
Francisco Melo, Manuela Veloso

Problem: many MAS solutions assume full joint sate observability because consider only local observability makes the problem too complex to be solved. But in many of these problems agent interactions are local. So they have to learn when interaction/coordination is advantageous. MDP and Q-learning is useed. And to show how it works, with an example of two robots that have to cross a gate.

They introduce a Coordination action (pseudo-action) and agents have to decide when to use this Coord action (it has a small penalty). Interesting method: agents can decide when to coordinate instead of exchange irrelevant messages all the time. They’ve tried with many different scenarios.

Abstraction Pathologies in Extensive Games
Kevin Waugh, Dave Schnizlein, Michael Bowling, Duane Szafron

Talking about poker competition for agents. Just two-playesrs. They use abstractions and the agent has to decice when to refine. Test with no-limit and leduc hold’em (small game, 6 cards deck, one ard ‘hidden’ and the other public). Boring… talking about the details of the game and many, many results.

State-Coupled Replicator Dynamics
Daniel Hennes, Karl Tuyls

Using evolutionary game theory, but it is single state dynamic, so it has to be extended to multi-state. Showing the behaviour in different classic games (as Prisoner’s Dilemma). Definitely…. i’m not interesting on this at all.

Wait a minute, with the examples I’ve seen hat it’s very similiar to our model of agreement, at least how it behaves. I’ll need to take a look to it. Too formal, but I hope that Alberto could help us with this.

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[AAMAS09] Perspectives and Challenges of Agent-Based Simulation as a Tool for Economics and Other Social Sciences

invited talk by Klaus G. Troitzsch

Human social systems are among the most complex systems in our world and they share several characteristics with agents. They’re different from physical systems and living systems. He’s talking about common concepts in agency from the viewpoint of human societies and comparing them sometimes with physical systems.

Before using agents, in social sciences many approaches has been used, as econophysics/sociophysics, game theory (OGM, again, I’m becoming hate it), some simulation attempts in the 60s… ups, I’ve just discovered that our model of agreement is sociophysics: agents as particles, with vectorial additivity for their behaviours.

Other interesting thing (related with the small world model I’m trying to find) is how humans take roles. People belong to many groups at the same time and we can not classify this groups in levels, because they co-exists. 

… and many other things as communication, emergence, adaptation or trust.
socially-inspired computing

What MAS can learn from economics and social sciences

  • more cooperative and secure agent societies
  • create adaptative sw if valid HSS simulators can be created
  • trust fromation and negotiation as design patterns for distributed systems engineering

but we’re far sway from creating socially-inspired computing systems.

At the end, too general, nothing really new and a bit boring.

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