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Questions tagged [scheduling]

For questions about methods that assign resources to work requests (e.g. processor time to tasks) usually minimizing some cost measure (e.g. makespan).

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Adopt constraint formulation

I have this constraint which ensures that there are at least $F$ consecutive days off. F.e. for $F=2$, an 1-0-1 is prevented. $$1+y_{it}\ge y_{i(t-1)}+y_{ik}~\forall i\in I, t\in\left\{ 2,\ldots,T- {F}...
Karl Seidl's user avatar
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30 views

Assigning resources to stations and tasks

I am new to operational research and using Gurobi for the following: I am trying to create a task allocation problem. There are 4 types of resources Skilled and Unskilled workers and Normal and ...
Rhitankar Saha Roy's user avatar
1 vote
2 answers
53 views

Improve a heuristic to solve the MS-RCPSP

I'm currently working on developing a heuristic to tackle the multi-skill resource constrained project scheduling problem (MS-RCPSP). I'd greatly appreciate any suggestions or modifications you may ...
John Donald's user avatar
1 vote
1 answer
34 views

General convention for demand determination

I am currently writing my first paper and therefore relatively new to the Operation Research community. I have a physician scheduling model with novel demands and now I want to test it. Since the ...
ornewbie's user avatar
-1 votes
0 answers
49 views

proof of NP-hardness

I have a scheduling problem and was wondering how to prove that the problem at hand is $NP$- hard? The model minimizes overstaffing and comes with normal scheduling constraints (demand, working hours ...
Karl Seidl's user avatar
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0 answers
34 views

Scheduling categories of jobs with completion time requirements

Consider a discrete time slotted, system with two categories of jobs $J_1$ and $J_2$, where each job from the category $J_1$ has completion time requirement of $C_1$ and the jobs from category $J_2$ ...
ephemeral's user avatar
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1 vote
1 answer
82 views

Schedule monotony constraints

Suppose I have a model for creating a nurse's duty roster. The model has the indices $i$ for the person, $t$ for the day and $s$ for the shift. I have the binary variable $x_{its}$ which indicates ...
manofthousandnames's user avatar
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1 answer
51 views

Is that an optimal solution for this instance of MS-RCPSP (Multi-Skilled Resource-Constrained Project Scheduling Problem)

I'm questioning whether this is the optimal solution for this instance of the MS-RCPSP (Multi-Skilled Resource-Constrained Project Scheduling Problem). I have checked the assignment and would like to ...
John Donald's user avatar
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45 views

Constraint formulation in MILP AGV Scheduling (using CPLEX)

I am currently working on a MILP formulation for optimizing AGV/AMR scheduling. The model aims to optimize task scheduling across multiple missions using a limited set of resources. Parameters such as ...
Rami's user avatar
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1 answer
69 views

Issue with Mathematical Model Using PuLP Library

I'm working on a pulp python code for the MS-RCPSP (multi-skilled resource-constrained project scheduling problem), I need to update the code to address a specific scenario: when an activity requires ...
John Donald's user avatar
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40 views

Network formulation based side constraints for a workforce scheduling problem

For a workforce scheduling problem, I have formulated the "at most one shift per day" constraint as a network formulation based side constraint (with other constraints like demand coverage, ...
SDC's user avatar
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Need help defining constraints regarding start and end time on job shop scheduling AGV

...
Rami's user avatar
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1 vote
2 answers
280 views

Efficient Algorithm for Scheduling 140 Predefined 1:1 Meetings with Variable Participant Constraints Over 7 Slots?

I’m tasked with organizing a large number (130) 1:1 meetings for 50 people across a limited number of time slots (7) during a conference. I am seeking advice on the best algorithmic approach to tackle ...
Toby's user avatar
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1 vote
1 answer
64 views

Complexity of average maximum completion time

There are $n$ jobs with different processing times, and they should be scheduled on $m$ identical machines such that the average (of all jobs, of all machines) maximum completion time (makespan) is ...
dspath's user avatar
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1 answer
50 views

multiple shifts per day constraint for a workforce scheduling problem

This is an extention to the workforce scheduling problem discussed in this thread Workforce scheduling problem. Adding a new post to discuss an important new requirement in this model. So the new ...
SDC's user avatar
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1 answer
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Scheduling optimization problem - Where to begin?

Class Scheduling Optimization for a Trade School We are exploring ways to model, simulate, and optimize class scheduling for a trade school, focusing on addressing the complex dynamics of managing ...
Evan's user avatar
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2 votes
1 answer
101 views

Workforce scheduling problem difficulty

I am working on a workforce scheduling MIP -- given a set of shift candidates (different shapes and sizes of shifts created out of labor demand) and a set of workers, optimally assign the shifts under ...
SDC's user avatar
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2 answers
68 views

Problem 8.17 of Korte and Vygen

An airline wants to conduct a given set of scheduled flights with as few airplanes as possible. All available airplanes are of the same type. For each flight we know the departure time and the flight ...
Nico Konrad's user avatar
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1 answer
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Scheduling: Connecting the end and the beginning of the planning horizon

I would like to create a rota that repeats every 28 days and adheres to the usual rules. These include the minimum/maximum number of consecutive working days and the break days. I have created a model ...
lukdooxb1's user avatar
1 vote
0 answers
37 views

Execution time of sequential asynchronous process and division of labour

I wasn't sure if I should put this question here, but I guess is as good as any. When we have a sequential process that has a number of tasks, were each task requires the previous one to be completed, ...
gabriel's user avatar
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2 votes
1 answer
250 views

Replace the constraint using ==> by a linear formulation

I would like to know how to express the continuity constraint without using a decision variable in the conditional form. My challenge is to stay with a linear formulation. I will start to explain my ...
Basma Ben Mahmoud's user avatar
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1 answer
47 views

Circular queue modeling

Let $P$ be a set of discretely interruptible processes/tasks; $T_i \in \mathbb{N}$ be the running time of process $i \in P$; And $\tau \in \mathbb{N}$ be the maximum amount of time a process can use ...
Matheus Diógenes Andrade's user avatar
2 votes
0 answers
53 views

Implement a rolling horizon approach into a schedulig problem

I have just come across the topic of 'Rolling Horizon' in my literature research and would now like to apply it myself, but unfortunately I don't know where to start. This is my model, which is ...
lukdooxb1's user avatar
2 votes
1 answer
237 views

How to modify a model to be cyclic?

I have the following question. I have the following physician problem with the indices $I$ (doctor), $T$ (days) and $J$ (shifts). $x_{itj}$ is the decision variable, $d_{tj}$ is the demand and $g$ is ...
manofthousandnames's user avatar
2 votes
2 answers
332 views

How to model weekend constraints in a nurse rostering problem?

I have the following problem. I have a Nurse rostering problem and want to model the following. I have the indices $D$ (days), $I$ (nurse), $S$ (shift). My planning period $D$ is 28 days. Now I want ...
Uni ewr's user avatar
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Workforce scheduling optimization using ML model output

I am working on a workforce scheduling problem where we want to come up with an intelligent way to identify a set of shift candidates that is just enough to cover all labor demand but also flexible ...
SDC's user avatar
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5 votes
2 answers
219 views

How to combine MIP solver with a CP one?

I am working on the scheduling problem in the class of parallel resource scheduling models. When I have studied some papers regarding that, I see the method that combines an MIP with a CP. The ...
A.Omidi's user avatar
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1 vote
1 answer
181 views

Job Scheduling with Energy Consumption using Linear Programming

I'm looking for some advice for an optimization problem regarding scheduling jobs in a datacenter. So I have a list of jobs and each job has a required time for finishing and a number of cores it has ...
wind.leon's user avatar
1 vote
2 answers
198 views

Workforce scheduling problem

I am working on a employee scheduling problems (assigning shifts to temporary workers) by modeling it as a MIP. There is a one shift per day constraint for the employees. There are overnight shifts ...
SDC's user avatar
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2 votes
1 answer
83 views

Compute time between tasks

I am trying to solve an optimization problem in which there is a set of tasks, $S$, where $s_i$ and $e_i$ are the starting and ending time of task $i \in S$. Each task $i $ must be done within its own ...
Christopher Expósito Izquierdo's user avatar
1 vote
1 answer
123 views

Scheduling & Routing Problem

Looking for some advice on how to approach this combo scheduling + routing problem. I am a supply chain OR consultant, and was recently approached by a potential client. Without giving too much away, ...
Ralph Asher's user avatar
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0 answers
130 views

Pyomo + Gurobi Scheduling Tasks within Working Hours

I initially posted this on stackoverflow and got redirected here. You can view the old post with formatted tables here: StackOverflow Post I have a python schedule optimization script using pyomo and ...
Phil Franjo's user avatar
2 votes
0 answers
32 views

The facet-defining inequalities for a single resource scheduling problem

Suppose, there exists a scheduling problem $S$, in this case a single resource, with the following descriptions: $$ \text{conv(S)} = \{x \in \mathbb{R}^n \ | \ \forall \lambda_{i} \in \mathbb{R}^{n+}, ...
A.Omidi's user avatar
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1 vote
1 answer
120 views

Can dynamic programming find globally optimal solutions for scheduling problems

I want to know if dynamic programming can generally find globaly optimal solutions for scheduling problems? I think this might be difficult as dynamic makes one at a time decisions without calculating ...
PeterBe's user avatar
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1 vote
1 answer
139 views

Mixed-Integer Programming Model for Scheduling with Dynamic Jobs

I have an optimization problem for deliveries between production lines and a warehouse in a small facility. I need to know how many vehicles and utilities to buy, such that cost and downtime are ...
user18463824's user avatar
1 vote
1 answer
155 views

Is this classed as a version of jobshop? How should it be approached?

I'm looking at a problem that seems quite like flexible jobshop, but as I understand it jobshop is basically all about finding the order/sequence of tasks (across multiple machines potentially), ...
Faolian's user avatar
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2 votes
1 answer
82 views

How to define the sequence depending setup time based on a time index formulation

I am working on a scheduling problem in which I have used two different MIP formulations and also based on the time index variable. My problem is in the class $ P_{j} | \ r_{j}, SDST \ | C_{Max} $. ...
A.Omidi's user avatar
  • 8,940
1 vote
0 answers
88 views

Optimize cherry picking runs

I am trying to optimize a cherry picking procedure on 96-well microplates. The plates are 12X8 (12 columns, 8 rows). We pass a command file that has many lines like this to a robot: ...
Ryan's user avatar
  • 111
2 votes
1 answer
100 views

Formulation for choosing how many items to manufacture

I am working on a scheduler for a manufacturing plant. I have currently set it up so the decision variables are set up as binary variables: $x_{m,p,s}$ = 1 if machine m is running part p on shift s ...
Dano's user avatar
  • 55
1 vote
1 answer
104 views

Scheduling repeated tasks with minimum duty cycles

Several tasks need to run repeatedly in a channel, one at a time, over a repeating time frame of length $T$. Associated to each task $i$ is the duration $L_i$ the task will take to run, and a maximum ...
Mark's user avatar
  • 111
1 vote
2 answers
102 views

In a routing and scheduling problem with break consideration, How can I determine whether a node is met before a break or after it?

I'm working on a routing and scheduling problem in the home care services context. I consider a break as a dummy patient, so routing and scheduling are also implemented for the break node (with some ...
Hani Jamshidian's user avatar
1 vote
0 answers
88 views

Linearization of Conditional Constraints for MIP using Cplex

I'm currently working on a mixed-integer programming (MIP) problem and I'm trying to implement a set of conditional constraints in CPlex. These constraints involve decision variables that are indexed ...
B.Kim's user avatar
  • 11
2 votes
1 answer
214 views

Compute overlapping time

I am trying to solve an optimization problem in which there is a set of tasks, $S$, where $s_i$ and $e_i$ are the starting and ending time of task $i \in S$. Each task $i $ must be done within its ...
Christopher Expósito Izquierdo's user avatar
2 votes
4 answers
133 views

How to fill the days in sequence?

I have a scheduling problem. 20 hours of work load should be assigned to different days (max 4 days are available and the capacity of ech day is 8 hours max) $\sum_i h_i = 20$ $0 \leq h_i \leq 8$ The ...
Optimization team's user avatar
2 votes
2 answers
399 views

Scheduling to minimize total "wait to start" time

I have a scheduling problem I am trying to work through. As I was outlining the problem, I realized it is probably of a known problem type, but I am unsure of what keywords to search for or what ...
Ike348's user avatar
  • 343
3 votes
1 answer
158 views

Meaning of the domain propagation in the context of mixed-integer programming

In the literature, domain propagation defines the process of inferring sequences of local domain reductions at the current node of the branch-and-bound tree. The goal is to shrink the size of the ...
A.Omidi's user avatar
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1 vote
2 answers
265 views

Best algorithm for scheduling interviews

I posted the same question on stackoverflow and immediately referred to post it here. I want to think about the best algorithm which let the interviewer meet maximum number of candidates. Suppose that ...
iyui's user avatar
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0 votes
2 answers
115 views

Assignment problem with multiple precedence constraints

Objective and short problem description The objective is to load as many passenger vehicles as possible on an auto-train. The train consists of multiple wagons with two levels each. The wagons are ...
Christian's user avatar
1 vote
2 answers
112 views

Modeling of a special form of the precedence constraint

There exists a scheduling problem in which some tasks should be processed on some resources. Additionally, each task needs to be assigned to a specific position on each resource. Let the decision ...
A.Omidi's user avatar
  • 8,940
0 votes
1 answer
59 views

Help finding linear constraint - LP

I have the following question. I have two variables $w_{nds}$ and $m_{nd}$. The first variable indicates whether a nurse $n$ works shift $s$ on day $d$. The second one indicates the motivation of ...
nflgreaternba's user avatar

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