Reasearch center in scientific and technical information Cerist Avignon, Dec 9-11 Bionetics 2009 Presented by: Hakima Mellah

Introduction Production systemsMulti Agents system(MAS)The self organiszng protocolMAS for production systemConclusion & perspectives 2

3 New communication flows emerge IS4 IS2 IS1 IS3 IS4 IS2 IS1 IS3 IS4 IS2 IS1 IS3’ IS4 IS2 IS1 The coordination and the maintenance of connectivity in a network take from peer to peer systems (P2P). One of the major problems characterizing this type of systems is the establishment and the maintenance of the co-operation between nodes. However, this difficulty can arise in any communication network, ad hoc network, multi agents systems(for which the node will be regarded as an agent,),…

4 A production system is a set of resources realizing a productive activity. The production is the transformation of resources (machines and materials) leading to the creation of goods or services. The transformation is done by a succession of operations (tasks) that use resources (machines and operators), and modify the raw materials or components that enter into the PS in order to create outgoing finished products of this system and assigned to be consumed by customers.  What is? (i) Information and decision subsystem (ii) physical production subsystem Systems Theory

5 Production System Example Features monitoringschedulingdispatching Task7 Task6 Task 5 Task 4 Task 3 Task2 Task1 Ffinished product Product semi- finished Produit semi- finished oroduct stock Machine F Machine E Machine D Machine B Machine A Machine C Transpor meant Transpor meant

6 The critical and important problem to solve within PS is fault tolerance. The control system must provide very powerful mechanisms fault tolerance in order to ensure the continuous operations of PS that are detection, prevention and correction,  What?  How? production management ? MULTI-AGENTS SYSTEMS Enterprise requirements Competitivity. Very high reliability constraints. Minimising dysfonctionning. What can offer a MAS decentralised control New manners to communicate.

MAS MAS is composed by autonomuous entities, called agents. They evolve in a common environment, have a collective behaviour to reach a desired function. Communication protocols: Contract Acquaintances Net protocol Model Organisation & self organisation Organisation is the way that a set is constituted and the action to organise. By SO, an agents organisation allows agents to adapt to changing situations. 7 C C C C S S C C P P P P P P P P

8 The principal goal through this protocol is to ensure: (i) New bonds of communications (ii) an important co-operation between the agents of the same neighbourhood; (iii) a MAS self organization made concrete by the emergence of communication bonds, that make cooperate agents which are not directly connected; (iv) take decision to add/remove agents when it is necessary;

 Concepts within BCComputational interpretation  Food Energie /information  Removing food sourceDestroy a link between sources, or the source itself.  Patterncommunication structure (organisation)  BacteriaIS component  ChemotaxisSearch direction  Gradient morphogenDistance compared to an IS; information of position  Inhibition & local competitionInformation on decision  Local Control Failures detection  9

10 Most important primitives Positioning process Election process Routing process Checking process Grouping process

11 Morphogen Gradient and information of position: - More the morphogen is diffused and more its concentration is higher. -Each gradient morphogen implies an activity assured by a bacteria group -morphogen concentration represents the distance between a bacteria and a source of food -Morphogen allows the bacteria to know where it is situated between two differents sources Figure 3. Morphogen diffusion Positioning process

12 Local inhibition and competition -Within a group, cells differentiate to take a new role. one cell that decide to differentiate, diffuses a signal (morphogen) that inhibit others to differentiate. Election process

 Mathematical formulation of positioning process:  A position message: position(a i, role, pos i ),   i  IN, a i  A, the whole of agents positions with their identification are stored in a table.   j  IN, a i  A, if e ij =1 a j  a j is a direct neighbour of a i and can received a i messages.   k  IN, a k  A / e ik =1   a k receives position(a i, role, pos i ),  a k receives position(a i, role, pos i ) for the first time  Pos src  pos i ; pos k  pos src +1; 13

Piloting ressource Agent(PRA) User Agent (UA) Interface Agent(IA) 14 UA IA PRA Setting production plan Dispatching tasks to PRA Realising piloting system functions

1. Agent failure  (i)RA(breakdown) is the alone agent of another RA.  (ii)RA has several neighbours.  2. Communication bond failure i)RA isolated or the system is broken down into two subsystems. (ii)Isolated RA is a neighbor of an agent RA belonging to a sub system. (iii)The two RA belong to the same subsystem. 1. Agent failure  (i)RA(breakdown) is the alone agent of another RA.  (ii)RA has several neighbours.  2. Communication bond failure i)RA isolated or the system is broken down into two subsystems. (ii)Isolated RA is a neighbor of an agent RA belonging to a sub system. (iii)The two RA belong to the same subsystem. 15 -Soft failure Agent in failure Communication bond destroyed

16 -Hard failure -At least one RA can execute the tasks of the agent responsible for the breakdown resource -No agent can perform the tasks of the breakdown agent and in this case the operator has to intervene. Fig. 2. Collaboration diagram of the system functioning t

Production system is able to be fault tolerant by: Detecting and localizing a failure finding a solution to each MAS situation Minimizing operator intervention 17

Realize the study on a concrete case of production systems. Considering a MAS in multi postes 18

19 THANK YOU FOR YOUR KIND ATTENTION Algiers by night

Université SAAD DAHLEB, Blida. USDB Présenté par : RAIAH AHMED & TIGUMOUNINE AREZKI 20

Reasearch center in scientific and technical information Cerist Avignon, Dec 9-11 Bionetics 2009 Presented by: Hakima Mellah