Facing the huge threats to European employment caused by globalisation and the pressure to increase productivity, a consortium of 3 large and 2 SME industrial end-users enhanced by 4 academic research groups skilled in Constraint an Integer Programming (CP&IP) as well as cutting planes (BC) and 2 developers of commercial IP and CP software proposes: the development of large scale integrated Supply Chain (SC) optimisation software supporting intelligent production, based on a deep integration of (IP/BC)&CP. The project builds on 2 successful ESPRIT projects and aims to extend existing BC&CP software to effectively solve problems in SC management. The consortium will, from an extensive set of end-users' problems, derive a generic structure suitable to BC&CP, establish links between the IC&CP codes, implement appropriate solution methods and produce industrial strength software to be applied by the end-users.
After 31/4 years of project-work, we can report the following achievements: A well-studied set of models and test cases from the end-users is available. These test cases cover a broad range of supply chain aspects, from supply chain design and planning:
- Strategic assessment of required buffer inventories and optimal levels of production capacity for make-to-order multi-stage systems;
- Long-term, multi-level, multi-product location problems;
- Medium-term, multi-product, multi-site, lot-sizing, sequencing/changeover problems in make-to-stock systems, to scheduling:
- Multi-stage, lot-sizing or fixed batch sizes, machine assignment and sequencing, limited storage capacity for intermediates and end-products in make-to-order and make-to-stock environments. Most of the test cases are defined based on common modelling conventions and efficient formulations have been found. Some of the cases benefited quite early in the project from new MIP cuts and/or CP global constraints and heuristics as well as from first co-operative approaches.
Based on the test cases, three generic supply chain models have been identified and documented. Agreed common modelling conventions are being used.
New CP global constraints, MIP cuts and separation heuristics have been identified, implemented and tuned for supply chain structures. The architectural software design has been defined and revised in order to serve as basis for further development. The work on the new enhanced modelling language Mosel is finished. The language has even got a larger set of functionalities than originally planned. It is in use inside as well as outside the LISCOS consortium. A revised software development platform is in use. The new modelling system - including the Mosel Native Interface, the Mosel libraries and the possibility to implement new Mosel modules - now supports integration of CP solvers and co-operative MIP/CP implementations as has already been proved.
The XPRESS framework for branch and cut is complete and has been implemented in a flexible development framework bc-shell, which is now also available as a Mosel module. The implementations of the new supply chain related MIP cuts into XPRESS and global constraints into CHIP are completed. The resulting prototype software tools BC-GEN and CP-GEN are available. The XPRESS and CHIP MP and CP solvers are linked and the API issues resolved. Effective forms of co-operation between CP and BC components have been identified, implemented and documented. Prototype BC/CP-GEN software templates are available.
The new software tools were successfully applied on more users' test cases than originally anticipated. The industrial partners already used their know-how gained in the project in other applications not directly covered by LISCOS test cases. Tools for dissemination and marketing are available and are used by all partners for their presentations of the project. A LISCOS flyer and web page (www.liscos.fc.ul.pt) provide information on LISCOS. Several relevant LISCOS publications are available. The project and its results were presented at appropriate conferences. Some results are released in the commercial products of Dash (ex: BCL, Mosel) and Cosytec (ex: new global constraints, CLIP), some will be released (ex: XPRESS-CP) in the near future.
Funding SchemeCSC - Cost-sharing contracts
NN7 3BX Blisworth
4430 Vila Nova De Gaia