MultiAgent Systems

Distributed Artificial Intelligence MultiAgent Systems Characteristics of MAS Challenges of MAS Networking Remote Method Invocation Uniform Resource Location

Distributed Problem Solving How a particular problem can be solved by a number of modules, which cooperate in dividing and sharing knowledge about the problem and its evolving solutions. All iteraction strategies are incoporated as an integral part of the system.

Distributed Problem Solving

MultiAgent Systems Concerned with the behavior of a collection of possibly pre-existing autonomous agents aiming at solving a given problem. a loosely coupled network of problem solvers that work together to solve problems that are beyond the individual capabilities or knowledge of each problem solver

MultiAgent Systems

Characteristics each agent has incomplete information, or capabilities for solving the problem, thus each agent has a limited viewpoint there is no global system control; data is decentralized; and computation is asynchronous.

Why MAS? the ability to provide robustness and efficiency; the ability to allow inter-operation of existing legacy systems; and the ability to solve problems in which data, expertise, or control is distributed.

Challenges How to formulate, describe, decompose, and allocate problems and synthesize results among a group of intelligent agents? How to enable agents to communicate and interact? What communication languages and protocols to use? What and when to communicate?

Challenges How to ensure that agents act coherently in making decisions or taking action, accommodating the non-local effects of local decisions and avoiding harmful interactions? How to enable individual agents to represent and reason about the actions, plans, and knowledge of other agents in order to coordinate with them? How to reason about the state of their coordinated process (e.g., initiation and completion)?

Challenges How to recognize and reconcile disparate viewpoints and conflicting intentions among a collection of agents trying to coordinate their actions? How to effectively balance local computation and communication? More generally, how to manage allocation of limited resources?

Challenges How to avoid or mitigate harmful overall system behavior, such as chaotic or oscillatory behavior? How to engineer and constrain practical MAS systems? How to design technology platforms and development methodologies for MAS?

Networking Open System Interconnection Socket –IP Address –Port ServerSocket RMI URL

OSI Model

Socket Construction Socket s = new Socket(hostName, port); Read from Socket BufferedReader r = new BufferedReader( new InputSreamReader(s.getInputStream()); Write to Socket PrintWriter o = new PrintWriter( s.getOutpuStream(), true); o.println(”message”);

ServerSocket

ServerSocket server = new ServerSocket(port); while (true) { Socket client = server.accept(); }

Remote Method Invocation

RMI Rmiregistry finds registry-name Server: Registry r = LocateRegistry.getRegistry(); r.rebind(Registry_Name, server); Client: Registry reg = LocateRegistry().getRegistry(); server = (RMIServer) reg.lookup(Registry_Name);

URL Make a URL URL s = new URL(” Read the source –Get object content: Object o = s.getContent(); –Convert o to InputStream: is = (InputStram)o; –Read each line from BufferedReader

URL Display a URL –LinkListener: Class LinkListener implements HyperlinkListener { public void hyperlinkUpdate(HyperlinkEvent e) { if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) showPage(e.getURL).toString()); } –showPage JEditorPane content; void showPage(String location) { try { content.setPage(location); } catch() {} }