- Scheduling seminar - list.iid.ciirc.cvut.cz

Thomas Lidbetter (Rutgers University) | June 4 | Min sum ordering problems with applications to scheduling
by Zdenek Hanzalek 02 Jun '25

02 Jun '25

Dear scheduling researcher, We are delighted to announce the talk given by Thomas Lidbetter (Rutgers University). The title is "Min sum ordering problems with applications to scheduling". The seminar will take place on Zoom on Wednesday, June 4 at 13:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/97914930603?pwd=6nVlX7rd8Izi32aF3kLIm00Wd1qbEa.1 Meeting ID: 979 1493 0603 Passcode: 477966 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A The abstract follows. We consider a large family of problems in which an ordering (or, more precisely, a chain of subsets) of a finite set must be chosen to minimize some weighted sum of costs. This family includes variations of min sum set cover, several scheduling and search problems, and problems in Boolean function evaluation. We define a problem, called the min sum ordering problem (MSOP), which generalizes all these problems using a cost and a weight function defined on subsets of a finite set. By making certain assumptions on the structure of the cost and weight functions, we derive general approximation results that can be applied to several problems. This talk will be based on two joint works with Robbert Fokkink, László Végh, Felix Happach and Lisa Hellerstein. The next talk in our series will be in September. For more details, please visit https://schedulingseminar.com/ With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Zhi-Long Chen (Univ of Maryland) | May 21 | Online Integrated Production and Distribution Scheduling
by Zdenek Hanzalek 19 May '25

19 May '25

Dear scheduling researcher, We are delighted to announce the talk given by Zhi-Long Chen (Univ of Maryland). The title is "Online Integrated Production and Distribution Scheduling". The seminar will take place on Zoom on Wednesday, May 21 at 13:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/96828038614?pwd=2muPtkXSwJC5pmFj9hLblhFPvUlHuZ.1 Meeting ID: 968 2803 8614 Passcode: 878236 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A The abstract follows. As a growing number of companies adopt make-to-order business model or sell their products online, we are seeing numerous decision problems that can be modeled as integrated production and distribution scheduling (IPDS) problems. In such problems, order processing and delivery must be scheduled jointly in order to achieve an optimal balance between total operational costs and overall customer service. Offline IPDS problems, in which the information about every order is known in advance with certainty, are extensively studied. However, research on online IPDS problems, in which orders arrive randomly with their information unknown until they arrive, is relatively recent but is growing rapidly. In this talk, we first describe two real-world applications to illustrate the importance of studying online IPDS problems from a practical point of view, and highlight the challenges in deriving good algorithms for online IPDS problems. We then focus on one specific problem and analyze an online algorithm for the problem. Finally, we provide an overview of this problem area and discuss possible topics for future research. The next talk in our series will be: Thomas Lidbetter (Rutgers University) | June 4 | Min sum ordering problems with applications to scheduling For more details, please visit https://schedulingseminar.com/ With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Rubing Chen (Zhengzhou University) | May 7 | Single-machine hierarchical scheduling with release dates and preemption to minimize the total completion time and a regular criterion
by Zdenek Hanzalek 05 May '25

05 May '25

Dear scheduling researcher, We are delighted to announce the talk given by Rubing Chen (Zhengzhou University). The title is "Single-machine hierarchical scheduling with release dates and preemption to minimize the total completion time and a regular criterion". The seminar will take place on Zoom on Wednesday, May 7 at 13:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/95815007611?pwd=uA3Wt322MOaLW9M9F8M7UErCNPiZaw.1 Meeting ID: 958 1500 7611 Passcode: 629296 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A The abstract follows. In this talk, we consider the single-machine hierarchical scheduling problems with release dates and preemption, where the primary criterion is the total completion time and the secondary criterion is an arbitrarily regular scheduling criterion, which is of either the sum-form or the max-form. We aim to find a feasible preemptive schedule that minimizes the secondary criterion, subject to the condition that the primary criterion is minimized. We show that the variants of the problems under study are polynomially solvable. To address these problems, we establish some hereditary properties for the feasible schedules and instances, and present a complete description of the feasible schedules through some elaborately constructed job-permutations. The next talk in our series will be: Zhi-Long Chen (Univ of Maryland) | May 21 | Online Integrated Production and Distribution Scheduling For more details, please visit https://schedulingseminar.com/ With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Premysl Sucha (CTU in Prague) | April 9 | Machine Learning Inside Decomposition of Scheduling Problems
by Zdenek Hanzalek 07 Apr '25

07 Apr '25

Dear scheduling researcher, We are delighted to announce the talk given by Premysl Sucha (CTU in Prague). The title is "Machine Learning Inside Decomposition of Scheduling Problems". The seminar will take place on Zoom on Wednesday, April 9 at 13:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/93077786062?pwd=Cj5lSGL0PI5el3qj3nBkbTXMh3ZTKc.1 Meeting ID: 930 7778 6062 Passcode: 851384 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A The abstract follows. Problem decomposition refers to general techniques for efficiently solving large instances. The fact that decomposition splits the problem into smaller subproblems and then combines their solutions into a solution to the original problem opens up many possibilities for applying machine learning. There are two main advantages why it is suitable. The first is that the subproblems are solved repeatedly/recursively, so similar instances are solved multiple times. The second is that the subproblems are smaller and thus easier to combine with machine learning. In this talk, we show two successful applications of machine learning to speed up scheduling algorithms based on decomposition techniques, namely branch and price and Lawler's decomposition. The talk by Christian Blum (IIIA-CSIC) planed on March 26 is cancelled due to personal reasons of the speaker. Nevertheless, the next talk in our series will be: Christian Blum (IIIA-CSIC) | April 23 | CMSA: A Hybrid Metaheuristic for Combinatorial Optimization For more details, please visit https://schedulingseminar.com/ With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Premysl Sucha (CTU in Prague) | April 9 | Machine Learning Inside Decomposition of Scheduling Problems
by Zdenek Hanzalek 25 Mar '25

25 Mar '25

Dear scheduling researcher, We are delighted to announce the talk given by Premysl Sucha (CTU in Prague). The title is "Machine Learning Inside Decomposition of Scheduling Problems". The seminar will take place on Zoom on Wednesday, April 9 at 13:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/93077786062?pwd=Cj5lSGL0PI5el3qj3nBkbTXMh3ZTKc.1 Meeting ID: 930 7778 6062 Passcode: 851384 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A The abstract follows. Problem decomposition refers to general techniques for efficiently solving large instances. The fact that decomposition splits the problem into smaller subproblems and then combines their solutions into a solution to the original problem opens up many possibilities for applying machine learning. There are two main advantages why it is suitable. The first is that the subproblems are solved repeatedly/recursively, so similar instances are solved multiple times. The second is that the subproblems are smaller and thus easier to combine with machine learning. In this talk, we show two successful applications of machine learning to speed up scheduling algorithms based on decomposition techniques, namely branch and price and Lawler's decomposition. The talk by Christian Blum (IIIA-CSIC) planed on March 26 is cancelled due to personal reasons of the speaker. Nevertheless, the next talk in our series will be: Christian Blum (IIIA-CSIC) | April 23 | CMSA: A Hybrid Metaheuristic for Combinatorial Optimization For more details, please visit https://schedulingseminar.com/ With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Daniele Vigo (Unibo CIRI-ICT) | March 12 | One Million ... and Beyond! Solving Huge-Scale Vehicle Routing Problems in a Handful of Minutes
by Zdenek Hanzalek 07 Mar '25

07 Mar '25

Dear scheduling researcher, We are delighted to announce the talk given by Daniele Vigo (Unibo CIRI-ICT). The title is "One Million ... and Beyond! Solving Huge-Scale Vehicle Routing Problems in a Handful of Minutes". The seminar will take place on Zoom on Wednesday, March 12 at 14:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/96957110178?pwd=buNswAwkpAcTOreAfQ2qHG5yZr0kJd.1 Meeting ID: 969 5711 0178 Passcode: 723073 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A The abstract follows. Vehicle routing is a hard and extensively studied combinatorial optimization problem which has numerous practical applications in transportation and logistics. In the last two decades several effective solution methods were proposed for the heuristic solution of the vehicle routing problem (VRP) and its many variants but most of these methods do not scale well with respect to the computing time when the size of the problem grows. We discuss a family of approaches, originated from the FILO framework, which were explicitly designed to obtain a linear growth of the computing time making it possible to solve very large instances with up to one million customers within a very limited computing time. The next talk in our series will be: Christian Blum (IIIA-CSIC) | March 26 | CMSA: A Hybrid Metaheuristic for Combinatorial Optimization For more details, please visit https://schedulingseminar.com/ With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Defeng Sun (DAO lab, NEU China) | February 12 | Combinatorial Benders approach to solve the Quay Crane Scheduling Problem
by Zdenek Hanzalek 10 Feb '25

10 Feb '25

Dear scheduling researcher, We are delighted to announce the talk given by Defeng Sun (DAO lab, NEU China). The title is " Combinatorial Benders approach to solve the Quay Crane Scheduling Problem". The seminar will take place on Zoom on Wednesday, February 12 at 14:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/94791685557?pwd=p6XThOlSYXm8cT9n4db8dcjNSbiBiw.1 Meeting ID: 947 9168 5557 Passcode: 218539 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A The abstract follows. We propose an exact decomposition approach to solve the Quay Crane Scheduling Problem (QCSP) in container terminals. The problem is decomposed into two simpler problems: a sequencing master problem and a scheduling sub-problem. The master problem explores possible operation sequencing solutions for the tasks, while the sub-problem determines the completion times for each task to avoid collisions among quay cranes. A series of combinatorial cuts based on minimum infeasible systems and minimum sub-optimal systems are generated to accelerate the algorithm convergence. Furthermore, we provide a cut selection strategy to generate tighter multiple cuts. Computational tests on benchmark instances verify the effectiveness of the proposed approach. The next talk in our series will be: Daniele Vigo (Unibo CIRI-ICT) | March 12 | One Million ... and Beyond! Solving Huge-Scale Vehicle Routing Problems in a Handful of Minutes For more details, please visit https://schedulingseminar.com/ With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Two postdoctoral positions in scheduling
by Zdeněk Hanzálek 10 Jan '25

10 Jan '25

We invite applications for the position of Postdoctoral Researcher in the Optimization Group at the Czech Technical University in Prague. The topics to be studied are: *Scheduling Algorithms for Energy-efficient Production* https://euraxess.ec.europa.eu/jobs/307376 <https://euraxess.ec.europa.eu/jobs/307376> *Hybridization of Constraint Programming**for Scheduling Problems with Complex Criteria * https://euraxess.ec.europa.eu/jobs/307390 <https://euraxess.ec.europa.eu/jobs/307390> The successful applicant will work in close collaboration with Zdenek Hanzalek within the large-scope project “Roboprox - Robotics and Advanced Industrial Production,” co-funded by the EU. The successful applicant will have, or be about to obtain, a Ph.D. degree in computer sciences or equivalent professional qualifications. Applicants should have research experience in a field closely related to scheduling, combinatorial optimization, and algorithm design/implementation. The position is up to 2 years. The jobs and application process are listedat Euraxess, with a deadline of 31st January 2025. -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Norbert Trautmann (University of Bern) | December 4 | Mixed-integer linear programming for project scheduling with resource-unit related constraints
by Zdeněk Hanzálek 02 Dec '24

02 Dec '24

Dear scheduling researcher, We are delighted to announce the talk given by Norbert Trautmann (University of Bern). The title is "Mixed-integer linear programming for project scheduling with resource-unit related constraints". The seminar will take place on Zoom on Wednesday, December 4 at 14:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/93745359018?pwd=WPl0pMPIc8GP7Ou2GxRTKzxusUqjow.1 <https://cesnet.zoom.us/j/93745359018?pwd=WPl0pMPIc8GP7Ou2GxRTKzxusUqjow.1> Meeting ID: 937 4535 9018 Passcode: 272218 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A <https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A> The abstract follows. The widely discussed Resource-Constrained Project Scheduling Problem (RCPSP) consists in devising a schedule for the execution of the project activities such that (a) the project duration is minimized, (b) the completion-start precedence between given pairs of activities is respected, and (c) at no time does the total demand of the in-progress activities exceed the available capacity of the various resource types required for the execution of the activities. In the literature, different formulations of the RCPSP have been presented as binary or mixed-binary linear optimization problems; according to the time representation, the two groups of discrete-time and continuous-time formulations can be distinguished. In many applications, resource types represent pools of equipment units or teams of people with specific skills. In this talk, we consider two novel variants of the RCPSP in which additional constraints related to the individual units of the various resource types have to be considered. In the first variant, the execution of the project is distributed across multiple sites, i.e., for the execution of each activity, a particular site must be selected; moreover, while some resource units are available only at a particular site, other resource units can be moved between sites, requiring some transportation time. In the second variant, the workload should be balanced among the individual units of each resource type. For both variants, we present a continuous-time assignment-based formulation as a mixed-binary linear optimization problem. The next talk in our series will be announced in January 2025. For more details, please visit https://schedulingseminar.com/ <https://schedulingseminar.com/> With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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Philippe Laborie (Hexaly) | November 20 | Hexaly Optimizer for Scheduling
by Zdeněk Hanzálek 18 Nov '24

18 Nov '24

Dear scheduling researcher, We are delighted to announce the talk given by Philippe Laborie (Hexaly). The title is " Hexaly Optimizer for Scheduling ". The seminar will take place on Zoom on Wednesday, November 20 at 14:00 UTC. Join Zoom Meeting https://cesnet.zoom.us/j/99723070697?pwd=UpfVCqZTGBxoCQMoJ7czR8p490QSyc.1 Meeting ID: 997 2307 0697 Passcode: 433986 You can follow the seminar online or offline on our Youtube channel as well: https://www.youtube.com/channel/UCUoCNnaAfw5NAntItILFn4A The abstract follows. Hexaly Optimizer is a model-and-run mathematical optimization solver that addresses a broad range of industrial optimization problems in the areas of supply chain and workforce management, such as routing, scheduling, packing, clustering, matching, assignment, or facility location. Its mathematical formalism extends classical Mixed-Integer Linear Programming with set, permutation and interval variables on which any usual algebraic operator (arithmetic, logic, relational, etc.) can be applied. Hexaly Optimizer is widely used in industry today, has performances often comparable to the best dedicated algorithms, allows compact modeling, scales well (with problem size and complexity) and is constantly improving. This seminar focuses on the use of Hexaly Optimizer to model and solve industrial scheduling problems. We show how to exploit the mathematical concepts of the input formalism to model several classic scheduling problems in an elegant and compact manner and give an idea of the solver's performance compared to the state of the art. Next, we outline the various techniques employed under the hood to produce good-quality primal and dual solutions like constraint propagation, local search, large neighborhood search, linear relaxations, scheduling heuristics, or exact scheduling algorithms on particular sub-problems. The next talk in our series will be: Norbert Trautmann (University of Bern) | December 4 | Mixed-integer linear programming for project scheduling with resource-unit related constraints For more details, please visit https://schedulingseminar.com/ With kind regards Zdenek Hanzalek, Michael Pinedo and Guohua Wan -- Zdenek Hanzalek Industrial Informatics Department, Czech Institute of Informatics, Robotics and Cybernetics, Czech Technical University in Prague, Jugoslavskych partyzanu 1580/3, 160 00 Prague 6, Czech Republic https://rtime.ciirc.cvut.cz/~hanzalek/

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