Multi agent Production Planning System

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					                                                                                                     CertiCon Applied Research




Multi-agent Production
  Planning System




                                        Solution to Industrial Production
                                                Planning Systems

                                               The multi-agent production planning
                                               system can be employed to provide
                                             planning in the environment where the
                                             features like distributiveness, modularity
                                             and easy reconfiguration are required.
                                              The general concept of agent-based
                                                planning tools can be modified for
                                            individual task definition and integrated
                                              into a more complex information ERP
                                                  system as one of its subsystems.




This research has been supported in part by European Commission's Information Technologies Programme IST within the frame of the projects:
         ExPlanTech – IST-1999-20171, Exploitation of Agent-based Production Planning Using the ProPlant Technology, years 2000–2002;
  ExtraPlanT – EUTIST AMI IST-2000-28221, Customization and Validation of the ProPlant Multi-Agent Technology in the Area of Extra-Enterprise
              Production Planning, Supply Chain Management and Optimization of Virtual Enterprise Operation, years 2002–2003.
          Introduction                                          Multi-Agent Systems
                                                             Automated workflow management systems have
Almost all of the project-oriented enterprises are facing    proved to be the driving force behind successful
the following problem: How to set the optimal                decision making in industry. Multi-agent systems (MAS)
production plan to effectively exploit the company           technology offers a convenient platform for workflow
resources while reaching the highest turnover? To keep       modelling. An environment where each agent
business running and to avoid such critical situations       represents a real information unit of the modelled
when the company production is not balanced (e.g.            enterprise is an appropriate model for optimization and
the company does not receive an optimal number of            visualization of flows of material, work, and information.
production orders able to manufacture) an extra
attention to a production planning must be paid.

Multi-agent production planning tool could be a choice
for SME’s where standard solution fails or is not
affordable. The solution is suitable for enterprises using
heterogeneous legacy systems.


         Methodology Description

The used technology is based on the latest research
achievements in the fields of distributed artificial
intelligence, agent based computing and production
planning.


Agent (Software agent) – An agent is a computer                Intelligent reasoning about the enterprise resources
system, that is situated in some environment, and that is      with the aim to produce accurate estimation of
capable of autonomous action in this environment in            project’s deadline and costs
order to meet its design objectives.                           System state update and maintenance
                                                               Re-plan, i.e. maintenance of the plans created so far
Multi-agent system – A multi-agent system (MAS)                in such a way that they are dynamically updated
consists of a group of agents that can take specific           with respect to eventual change in co-operating
roles within an organizational structure. Multi–agent          agents (e.g. resource/agent breakdown).
system (multiple interconnected agents) represents the
decentralized nature of the problem. The agents need         Besides workflow management, the multi-agent
to interact with one another to meet their individual        technology is very much suitable for manufacturing
objectives/goals and common goal as well.                    processes simulation, production control as much as
                                                             scheduling, planning and re-planning.
Agentification – An agent wrapper implements the
agent-to-agent communication and integrates a pre-              Integration
existing software system. Such a software system             The enterprise management does not need to replace
becomes an agent – a fully-fledged member of the             the currently running information systems by a
multi-agent system.                                          completely new technology, while it make the best use
FIPA – The Foundation for Intelligent Physical Agents FIPA   of the technology they already have and the modern
is a non-profit organisation aimed at producing              multi-agent production planning technology.
software standards for the interoperation of                 Existing software systems that administer the production
heterogeneous and interacting software agents and            process within the enterprise (such as enterprise
agent-based systems.                                         resource planning systems (ERP), material
JADE – Multi-agent platform and en environment for           management, human resource systems, CAD/CAM
development of multi-agent applications. JADE comply         systems) are exploited by their agentification. An agent
with the latest FIPA 2000 specifications. JADE is            wrapper that implements the agent-to-agent
implemented in JAVA 1.2 and has no further                   communication wraps an agentified software system.
dependency on a third-party software.                        Such a software system becomes an agent – a fully-
                                                             fledged member of the multi-agent system.
   Advantages
The main features and the most interesting properties of
using the agent based systems in contrast with the
conventional software systems are scalability,
modularity, online reconfigurability. Agent approach
adopts principles and advantages of distributed
algorithms (parallel computing).
  System Architecture                                                   Supply Chain Management
The organizational structure of the multi-agent system
mirrors the organizational structure of the given             The multi-agent technology can be used for supply
enterprise. The agents have been divided into two             chain management and creating virtual organization.
fundamental super-classes: intra-enterprise (IEA) agents      Similarly to agentification of the factory legacy systems
and extra-enterprise (EEA) agents. IEAs represent the         or hardware machinery, one can integrate ERP systems
distributed planning system while EEAs provide passive/       of collaborators, suppliers and customers. Integrated
active access to the enterprise data. Special instance of     supply chain management requires solution for security
EEA is so called Enterprise-to-Enterprise Agent (E2E)         and authentication, trust, long term business processes
which connects two enterprises that may want to               optimization, ubiquity and openness.
participate in a supply chain.

    Algorithms
Agents technology allows planning algorithms to be
distributed throughout the system. The planning
algorithms work in real-time, so the overall plan is
reprocessed immediately when new task appears or in
case of a crucial change in the production. We
recognize two main levels of the task planning. In the
first level the task is decomposed to the parts (sub-tasks)
that can be processed by second planning level. The
first level controls sub-tasks time ordering and
overlapping. The second level is responsible for
resource allocation on specific departments. Each
department is represented by an agent, which
maintains resources for it and makes demanded
schedules. The scheduling algorithm takes into account
priority of the tasks, appropriate planning strategy (e.g.
eager or lazy) and minimizes possibility of tasks lateness.
Dynamic re-scheduling allows system to react to
production feedback (and to every production-
planning-relevant event) in very short time. Both levels
together guarantee
maximal utilization of the
factory departments and
keeping important
production constrains (e.g.
deadlines).

   Workflow Visualization
   and Access
Visualization of the plans,
available or booked
resources can remarkably
help a user to reveal and
then solve for example
resources bottlenecks.
Presentation and
visualization of the results of
the planning process help
to decide what order is to
be accepted in other words what order is the most
suitable in terms of the balanced production load.
Production data can (about workshops, orders, material
etc.) be accessed via the Internet in an ordinary web-
browser. Apart from the portable or the desktop PC, it is
possible to install the extra-enterprise agents on the
mobile PDA devices that are based on the Windows CE
platform. The extra-enterprise agents’ wrapper is also
adapted for communication with the Wireless Application
Protocol (WAP) for running in the cell-phone devices.
       Practical Utilization of Multi-Agent
Production Planning System Methodology
  Case Study
Multi-agent production planning
system is operating in the LIAZ
Pattern Shop (Liberec, Czech
Republic) with the aim to improve
control of manufacturing
processes. LIAZ Pattern Shop is a
manufacturing enterprise that is
engaged in production of
patterns, core boxes, permanent
moulds and dies for foundries
and tooling for high volume
production mostly in the
automotive industry. It has also
contributed to better utilization of
the factory resources, setting of
realistic targets and as well as to
customer service improvement.




                                                                       The technology has been successfully tested also in the
                                                                       Hatzapoulos SA, a Greek manufacturing enterprise
                                                                       providing packaging to transnational chains. Multi-agent
                                                                       technology has been integrated with a classical three-tier
                                                                       ERP system Atlantis (Unisoft Software, Altec SA, Greece).

                                                                          Success Stories – Referential Application
                                                                       Multi-agent production planning system (ExPlantech/
                                                                       ExtraPlanT) is integrated within legacy system
                                                                       (heterogeneous ERP) in the LIAZ Pattern Shop. Planning
                                                                       tool provides an operator with a global long term view on
                                                                       the production on factory level. An operator can easily
                                                                       inspect production on particular workshop as well. The
                                                                       system is also used as decision support tool during the
                                                                       new orders’ acceptance phase. The system carries out
                                                                       on-line re-planning re-scheduling so an operator
                                                                       immediately knows how the production would be
                                                                       affected by new incoming orders. At the first round the
                                                                       system works with the estimations on needed resources.
                                                                       As soon as the production starts the system collects data
                                                                       about finished jobs and revises the plans and schedules.
                                                                       Reference: http://www.modelarna-liaz.cz




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