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Introduction Research overview Applications of Stochastic Constraint Programming in Supply Chain and Operations Management Dr Roberto Rossi1 1 Management Science & Business Economics, The University of Edinburgh Business School, UK Logistics, Decision and Information Sciences, Wageningen University, the Netherlands The University of Edinburgh, March 2012 Conclusions Introduction Research overview Conclusions Background information Introducing myself... Current Lecturer Management Science Roberto Rossi PhD (Cork) MEng (Bologna) BEng (Bologna) External Assistant Professor Logistics Decision and Information Sciences External Fellow Wageningen School of Social Sciences Past Lecturer University College Cork (UCC) Postdoctoral researcher Cork Constraint Computation Center (4C) PhD Student Centre for Telecommunication Value Chain Research, 4C, UCC Introduction Research overview Conclusions Background information Introducing myself... Current: Roberto Rossi Assistant Professor Logistics, Decision and Information Sciences Research Projects Microbiological Risk Assessment in Logistic Chain Modeling Logistics Modelling of Pork Supply Chains Past: Lecturer University College Cork, Ireland Postdoctoral Researcher Cork Constraint Computation Center PhD Student Cork Constraint Computation Center University College Cork, Ireland Ph.D (Cork) M.Eng (Bologna) B.Eng (Bologna) Introduction Research overview Conclusions Background information Areas of expertise SC/OM P oduct low In orma ion low Re ail demand Prod cer Transport DC Consumer demand Transport Reta ou let Transport + + Consumer AI + + + + + Producer DC Re ail s ore + Demand centro d Operations Research Introduction Research overview Conclusions Background information Areas of expertise SC/OM P oduct low In orma ion low Re ail demand Prod cer Transport DC Consumer demand Transport Reta ou let Transport AI Consumer + + + Cross-fertilization of ideas + + + + Producer DC Re ail s ore + Demand centro d Operations Research Introduction Research overview Conclusions Background information R Rossi, S A Tarim, B Hnich and S Prestwich, "Constraint Programming for Stochastic Inventory Systems under Shortage Cost", submitted to Annals of Operations Reseach io n ... S A Tarim, B Hnich, R Rossi and S Prestwich, "Cost-based Filtering Techniques for Stochastic Inventory Control under Service Level Constraints", Constraints, Springer Verlag, Vol 14(2):137 176, 2009 tio R Rossi, S A Tarim, R Bollapragada, "Constraint-based Local Search for Computing Non-Stationary Replenishment Cycle Policy under Stochastic Lead-times", IJOC, forthcoming in m m co is ur et ah e ra ns t m co tic tp ro gr a ... m Artificial Intelligence & Computer Science in st oc m in ap g pr st oa -b c h as lo ed es gi c fil te pr rin og g ra m m in g in g ro og rp ea in rl pr ha st ic pr og ge m ic te in na dy ix ed m g m in g nv ex re l co ns at op gr tim Operations ra ra am ax Research m a m iz Research Topics & Recent Publications (2009/10) R Rossi, S A Tarim, B Hnich, S Prestwich and Cahit Guren, "A Note on Liu-Iwamura's Dependent-Chance Programming" European Journal of Operations Reseach,Vol 198(3):983 986, 2009 Introduction Research overview Conclusions Background information Research Topics & Recent Publications (2009/10) R Rossi, S A Tarim, B Hnich and S Prestwich, "Cost based Domain Filtering for Stochastic Constraint Programming", In proceedings of The 14th International Conference on Principle and Practice of Constraint Programming (CP 2008), Sep 14 18, 2008, Sydney, Australia, Lecture Notes in Computer Science, Springer Verlag, LNCS 5202, pp 235 250, 2008 SCM and OM R Rossi, S A Tarim, B Hnich and S Prestwich, "Computing Replenishment Cycle Policy under Non stationary Stochastic Lead Time", International Journal of Production Economics, Elsevier, Vol 127(1) 180 189, 2010 R Rossi, S A Tarim, B Hnich and S Prestwich, "Dynamic Programming for computing (Rn,Sn) policy parameters", International Journal of Production Economics, Elsevier, forthcoming R Rossi, S A Tarim, B Hnich, S Prestwich and S Karacaer, "Scheduling Internal Audit Activities: A Stochastic Combinatorial Optimization Problem", Journal of Combinatorial Optimization, Vol 19(3) 325 346, 2010 M ix ed In te St oc ha s E tic C ve C ge D on nt on r yn s -D s Pr Li tra a tr r ne oa ar mic aint iven int ct iv Pr P P P P e og rog rog ro rog St ra r r b oc r m am am abil am ha m m m is m st in i ng ing tic ing i c g Q Sc ua he In nt du ve ita lin nt tiv Su or g e pp y R C i sk lie on r M Õs tro St a C oc na l ap ha ge ac st m ity ic en Al Su t lo pp ca lie tio rÕs n Le ad tim e ... .. Approaches . S A Tarim, B Hnich, S Prestwich and R Rossi, "Finding Reliable Solutions Event Driven Probabilistic Constraint Programming", Annals of Operations Research, Springer Verlag, Vol 171(1) 77 99, 2009 S A Tarim, U Ozen, M K Dogru, R Rossi, "An Efficient Hybrid Approach for Computing (Rn,Sn) Policy Parameters", submitted to the European Journal of Operational Research Introduction Research overview Background information Research Statement My research is focused on automated reasoning. I develop systems that aim to be robust and scalable in such a way as to enable computers to act intelligently in increasingly complex real world settings and in uncertain environments. Conclusions Introduction Research overview Conclusions Background information Research Statement Chacko (1991) defines decision-making as “the commitment of resources today for results tomorrow” according to Oreskes (Stanford Univ.) “because decisions involve expectations about the future, they always involve uncertainty” G. Chacko, Decision-making under uncertainty: An Applied Statistics Approach, New York, 1991, quote on p. 5 Introduction Research overview Constraint Programming Constraint Programming Sample CSP V = {x, y, z} D(x) = {2, 3} D(y) = {1, 2, 3, 4} D(z) = {1, 2} C = {c1 : x + y ≤ 4, c2 : alldifferent(x,y,z)} Conclusions Introduction Research overview Conclusions Constraint Programming Constraint Programming Sample CSP V = {x, y, z} D(x) = {2, 3} D(y) = {1, 2, 3, 4} D(z) = {1, 2} C = {c1 : x + y ≤ 4, c2 : alldifferent(x,y,z)} We apply constraint propagation until no new deduction can be made... Introduction Research overview Conclusions Constraint Programming Constraint Programming Sample CSP V = {x, y, z} D(x) = {2, 3} D(y) = {1, 2, 3, 4} D(z) = {1, 2} C = {c1 : x + y ≤ 4, c2 : alldifferent(x,y,z)} We apply constraint propagation until no new deduction can be made... Sample CSP x ∈ {2, 3} y ∈ {1, 2, 3, 4} z ∈ {1, 2} Introduction Research overview Conclusions Constraint Programming Constraint Programming Sample CSP V = {x, y, z} D(x) = {2, 3} D(y) = {1, 2, 3, 4} D(z) = {1, 2} C = {c1 : x + y ≤ 4, c2 : alldifferent(x,y,z)} We apply constraint propagation until no new deduction can be made... Sample CSP x ∈ {2, 3} y ∈ {1, 2, 3, 4} z ∈ {1, 2} (c1 ) −→ x ∈ {2, 3} y ∈ {1, 2} z ∈ {1, 2} Introduction Research overview Conclusions Constraint Programming Constraint Programming Sample CSP V = {x, y, z} D(x) = {2, 3} D(y) = {1, 2, 3, 4} D(z) = {1, 2} C = {c1 : x + y ≤ 4, c2 : alldifferent(x,y,z)} We apply constraint propagation until no new deduction can be made... Sample CSP x ∈ {2, 3} y ∈ {1, 2, 3, 4} z ∈ {1, 2} (c1 ) −→ x ∈ {2, 3} y ∈ {1, 2} z ∈ {1, 2} (c2 ) −→ x ∈ {3} y ∈ {1, 2} z ∈ {1, 2} Introduction Research overview Conclusions Constraint Programming Constraint Programming Sample CSP V = {x, y, z} D(x) = {2, 3} D(y) = {1, 2, 3, 4} D(z) = {1, 2} C = {c1 : x + y ≤ 4, c2 : alldifferent(x,y,z)} We apply constraint propagation until no new deduction can be made... Sample CSP x ∈ {2, 3} y ∈ {1, 2, 3, 4} z ∈ {1, 2} (c1 ) −→ x ∈ {2, 3} y ∈ {1, 2} z ∈ {1, 2} (c2 ) −→ x ∈ {3} y ∈ {1, 2} z ∈ {1, 2} (c1 ) −→ x ∈ {3} y ∈ {1} z ∈ {1, 2} Introduction Research overview Conclusions Constraint Programming Constraint Programming Sample CSP V = {x, y, z} D(x) = {2, 3} D(y) = {1, 2, 3, 4} D(z) = {1, 2} C = {c1 : x + y ≤ 4, c2 : alldifferent(x,y,z)} We apply constraint propagation until no new deduction can be made... Sample CSP x ∈ {2, 3} y ∈ {1, 2, 3, 4} z ∈ {1, 2} (c1 ) −→ x ∈ {2, 3} y ∈ {1, 2} z ∈ {1, 2} (c2 ) −→ x ∈ {3} y ∈ {1, 2} z ∈ {1, 2} (c1 ) −→ x ∈ {3} y ∈ {1} z ∈ {1, 2} (c2 ) −→ x ∈ {3} y ∈ {1} z ∈ {2} Introduction Research overview Stochastic Constraint Programming Stochastic Constraint Programming (Walsh, 2002) Sample SCSP V1 = {x1 } V2 = {x2 } D(x1 ) = {1, . . . , 4} D(x2 ) = {3, . . . , 6} S1 = {s1 } S2 = {s2 } pmf(s1 ) = {(0.5)5, (0.5)4} pmf(s2 ) = {(0.5)3, (0.5)4} c1 : Pr{s1 x1 + s2 x2 ≥ 30} ≥ 0.75 C= c2 : Pr{s2 x1 = 12} ≥ 0.5; L = [hV1 , S1 i, hV2 , S2 i] Conclusions Introduction Research overview Conclusions Stochastic Constraint Programming Stochastic Constraint Programming (Walsh, 2002) V1 S1 V2 x21 x1 4 Scenario probability S2 s2 4 s2 3 C 0.25 c1: 5á3 + 4á4 ³ 30 c2: 4á3 12 s1 5 0.25 c1: 5á3 + 3á4 < 30 c2: 3á3 12 s1 4 0.25 c1: 4á3 + 4á6 ³ 30 c2: 4á3 12 0.25 c1: 4á3 + 3á6 ³ 30 c2: 3á3 12 3 x22 6 s2 4 s2 3 Introduction Research overview Stochastic Constraint Programming Stochastic Constraint Programming (Rossi, 2008) Sample SCSP V = {x, y, z} D(x) = {2, 3} D(y) = {1, 2, 3, 4} D(z) = {1, 2} S = {r } pmf(r ) = {(0.5)3, (0.5)2} C = {c1 : Pr{alldifferent(x+r,y,z)} ≥ α} L = [hV , Si] Conclusions Introduction Research overview Stochastic Constraint Programming Stochastic Constraint Programming (Rossi, 2008) Global Chance-Constraints (Rossi et al., 2008) Global Chance-Constraints performing optimality reasoning are called Optimization-Oriented Global Chance-Constraints (Rossi et al., 2008). Conclusions Introduction Research overview Stochastic Constraint Programming Stochastic Constraint Programming (Rossi, 2011) Constraints: (1) cumulative(s, e, t, c, m) Decision variables: sk ∈ {rk , . . . , dk }, ∀k ∈ 1, . . . , |K | ek ∈ {rk , . . . , dk }, ∀k ∈ 1, . . . , |K | Figure: A CSP for the deterministic multiprocessor scheduling. Conclusions Introduction Research overview Conclusions Stochastic Constraint Programming Stochastic Constraint Programming (Rossi, 2011) Constraints: (1) Pr {cumulative(s, e, t, c, m)} ≥ θ Decision variables: sk ∈ {rk , . . . , dk }, ∀k ∈ 1, . . . , |K | ek ∈ {rk , . . . , dk }, ∀k ∈ 1, . . . , |K | Stochastic variables: tk → processing time of order k ∀k ∈ 1, . . . , |K | Stage structure: V1 = {s1 , s2 , . . . , s|K | } S1 = {t1 , t2 . . . , t|K | } V2 = {e1 , e2 , . . . , e|K | } S2 = {} L = [hV1 , S1 i, hV2 , S2 i] Figure: A SCSP for chance-constrained multiprocessor scheduling. Introduction Research overview Stochastic Constraint Programming Ongoing Research B. Hnich, R. Rossi, S. A. Tarim and S. Prestwich, "Synthesizing Filtering Algorithms for Global Chance-Constraints", In Proceedings of the 15th International Conference on Principles and Practice of Constraint Programming (CP 09), September 21 24, 2009, Lisbon, Portugal, Lecture Notes in Computer Science, Springer Verlag, LNCS 5732, pp.439 453, 2009 ...a generic filtering strategy for porting any existing global constraint into a stochastic setting... in submission to Artificial Intelligence Conclusions Introduction Research overview Stochastic Constraint Programming Ongoing Research 22nd International Joint Conference on Artificial Intelligence (IJCAI-11) Conclusions Introduction Research overview Conclusions Stochastic Constraint Programming Ongoing Research V1 S1 V2 Scenario probability S2 2/3 x21 x1 4 s2 4 s2 3 s1 5 0 s1 4 1/3 C c1: 5á3 + 4á4 ³ 30 c2: 4á3 12 3 x22 6 s2 4 s2 3 0 c1: 4á3 + 4á6 ³ 30 c2: 4á3 12 Introduction Research overview Conclusions Final remarks Further Research Topics i. Newsvendor under partial demand information (ongoing). the decision maker knows the distribution of the demand but not the associated parameters a set of samples are given in place of the actual parameters ii. Sample Average Approximation for Quality Controlled Logistic in Slaughterhouse Supply Planning (ongoing) iii. Computing Replenishment Cycle Policy Parameters for Perishable Items with Non-Stationary Stochastic Demand Introduction Research overview Final remarks In Preparation A Springer book on The Replenishment Cycle Policy and its applications A Springer book on Stochastic Constraint Programming in collaboration with S. A. Tarim, B. Hnich, and S. Prestwich Conclusions Introduction Final remarks Questions Research overview Conclusions