Questions about the optimisation problem of ordering a set of tasks so that some objective function (e.g. makespan) is minimised. The set of constraints is crucial; in particular, there is a large body of research covering online variants. Use the process-scheduling tag for questions specifically ...

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Interval Scheduling Problem with Three Resources

So I am trying to figure out what kind of algorithm I would use if I wanted to implement the ISP with a predefined number of resources. Consider this example interval scheduling problem. Say there ...
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0answers
35 views

How to schedule different elements in a 24h range?

Given the following conditions: An element has: A time range, for example: 9:00 to 18:00. A repeat time, for example: every 5 minutes. Then a device recieves some elements and has to schedule ...
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18 views

Parallel Machine Scheduling test data

I am writing optimization program for unrelated parallel machine scheduling problem on CUDA. Now, the only thing I am missing are some test cases. Does anyone know where I can find such data? I have ...
2
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1answer
24 views

Who was the first to define Flow Shop / Job Shop problem?

I spent some time to search in internet who was the first to formaly define Flow Shop and Job Shop problems but with no effect. I'm especially interested in article/book so I can mention it in my ...
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1answer
17 views

How does Logical Block Addressing affect OS disk scheduling optimizations such as SCAN (Elevator Algorithm)?

If the OS is scanning from one edge of the disk to the other, doing so from behind the Logical Block Addressing (LBA) abstraction, although it may aim to service requests in an elevator-like way, what ...
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2answers
105 views

Is this special case of a scheduling problem solvable in linear time?

Alice, a student, has a lot of homework over the next weeks. Each item of homework takes her exactly one day. Each item also has a deadline, and a negative impact on her grades (assume a real number,...
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1answer
27 views

How to choose waiting process in a preemptive priority-based scheduler

If my CPU schedule is preemptive priority, and I have no new processes coming, how I should choose from the waiting processes?
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1answer
46 views

Rate Monotonic First Fit vs. Rate Monotonic Next Fit vs. Proportionate Fair

What would an example of a set of tasks be, where RMFF, RMNF and P-Fair all result in a different number of processors required?
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1answer
105 views

How and which component of an Operating System is responsible for the transition of a process from the blocked state to the ready queue?

A process in an Operating System is considered to occupy several states and a process transitions between these states. A scheduler is responsible for assigning CPU time to a process. However, a ...
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1answer
43 views

Distributed parallel computing algorithms for content dependent data

I have implemented group of pictures parallelism for hevc encoding on distributed platform. In this we have to send different video chunks to different machines, these machines encode data in parallel ...
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35 views

Problems of cyclic executive approach for scheduling of real time systems

I have a doubt on the cyclic executive approach for scheduling on real time systems. From Alan Burns's book Real-time Systems and Programming Languages. This final property represents one of the ...
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1answer
42 views

Are there any papers published proving how University Time Table Scheduling Problem is NP-Complete?

I have been researching on finding optimal solutions to generating University Time Table using Genetic Algorithm. I am searching for a Academic Paper, that properly defines the University Time Table ...
4
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0answers
43 views

job scheduling with deadline and two cascaded machines

Given a set of $N$ jobs and two machines A and B, each machine can process only one job at a time. Each job, if processed, must be processed by machine A before processed by machine B. The processing ...
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1answer
36 views

Scheduling problem on bipartite graph

Consider a bipartite graph $G=(U, V, E)$. Each $v \in V$ represents a soccer team, and each $u \in U$ represents a mini-tournament needs to be scheduled. If $u_i$ and $u_j$ share no common neighbor, ...
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1answer
25 views

Understanding the P2||CMax scheduling problem

I have a problem with understanding the $P_2 \mid \mid C_\max$ problem which is also known as Tasks Scheduling on Multiple Processors. In fact, in my case I need only one processor (but the problem ...
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1answer
62 views

Scheduling distributed computational graph

I work in computational fluid dynamics. And I spend most of my time waiting for simulation to complete. The common way to improve simulation performance is to use a suitable distributed linear ...
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0answers
63 views

Integer programming for the courier (goods delivery) scheduling problem

Model: Consider an undirected, weighted, complete graph $G = (V, E = V \times V, w: E \to \mathbb{N}^{+}, r: V \to \mathbb{N}^{+}, d: V \to \mathbb{N}^{+})$. $s \in V$ is a source vertex. $G$ ...
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1answer
17 views

How to understand the mathematical constraint of potentials?

Good evening! I am studying scheduling problems and I have some difficulties understanding constraints of potentials: Let be $t_j$ the time when a task $j$ starts, and $t_i$ the time when a task $i$ ...
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1answer
279 views

Using dynamic programming to maximize work done

Say that there are $n$ days and there is $x_1, x_2, ...,x_n$ amount of data to process on each day. Your computer can process $s_1$ amount of work on the first day since rebooting your computer, $s_2$ ...
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0answers
45 views

Algorithm to collect items before they expire

I thought about the following problem: There are goods $\mathbb{G} = (g_1, \dots, g_k)$ on the line. Coordinates are expressed in meters and sorted in increasing order. All goods have different ...
4
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2answers
139 views

Schedule tasks from a weighted list with time frame constraints

I'm attempting to create an automatic scheduler from a list of tasks I have available. Here are the key points: Each task has been given a priority beforehand and the algorithm should try to ...
3
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1answer
97 views

NP-hardness of a scheduling problem

Problem: Given an undirected, weighted, complete graph $G = (V, E, w, c)$. $w$ is the time weight function on edges, $w:E \to \mathbb{N}^{+}$; $w(e)$ represents the time it takes to travel along edge $...
5
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2answers
200 views

Schedule two trains whose tracks overlap so they don't crash

I've encountered scheduling problems in my algorithms class before like the type we use vertex cover to solve. Recently I was asked this question and did not even know what algorithmic technique to ...
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0answers
50 views

Optimality of EDF

For Earliest Deadline First, I have read that if utilization is less or equal to 1, the task set is schedulable under EDF. But does this criteria expresses the optimality for EDF? If not, how can we ...
2
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1answer
33 views

How profiling is done in trace scheduling?

I'm trying to understand how trace scheduling works. The book that I'm reading, Engineering a Compiler by Keith D. Cooper & Linda Torczon, states that this method is using profiling. Profiling ...
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1answer
89 views

Time quantum assignment to processes

In a book I am reading it is stated that an input/output intensive process should receive a higher time quantum whereas a computing intensive process on the other hand should receive a lower one. Here ...
5
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1answer
769 views

Weighted interval scheduling with m-machines

I am looking for some advice and direction on solving the weighted interval scheduling problem with $m$-machines to plan some experimental "wet lab" procedures. The problem is very similar to the ...
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0answers
362 views

Algorithm for scheduling timetable for student management system

I am developing the timetable module for a student management system. I am finding it difficult to design/develop it. It can be assumed that a given teacher is capable of teaching any standard whether ...
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0answers
31 views

Activity scheduling with activities that can move around

In this problem. I have a set of "activities" which can happen. Each "activity" is associated with several values: Duration: The length of time the activity takes Earliest time to start: The ...
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1answer
42 views

Why can no task have a utilization rate greater than one?

Let $C_i$ be the execution time for task i, $T_i$ be the task period and utilization rate $U = \frac{C_i}{T_i}$ Then $U$ must be less or equal to $1$ for the task to be schedulable Proof: ...
1
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1answer
79 views

Designing a scheduling algorithm

I have only intro CS under my belt, so I'm looking for some fast advice. I want to write a scheduling algorithm for the following scenario. I have customers who have selected how many hours they want ...
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1answer
114 views

Scheduling Problem Optimisation using LP solvers

I am currently working on a scheduling system which schedules individuals based on timeslots that have the following attributes: (1) Day of Week (2) Month (3) Session(AM/PM). The individuals ...
1
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1answer
80 views

Is Starvation Possible in LOOK Algorithm

The LOOK algorithm (wiki) is the same as the SCAN algorithm in that it also honors requests on both sweep direction of the disk head, however, this algorithm "Looks" ahead to see if there are any ...
2
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0answers
44 views

Optimize sequence when item costs are interdependent

I'm tempted to phrase this question notationally, but I may be jumping the gun on the exact problem definition as well. So let me start with the real-world scenario and work forward from there. You'...
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1answer
37 views

Is there a difference between the name scheduler and scheduling?

Sometimes I read about the term "scheduler" (offline-scheduler, online-scheduler,...) and then I see terms called "scheduling" (offline-scheduling, online-scheduling, preemptive scheduling, non ...
2
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1answer
577 views

Can Shortest Job First Scheduling be subject to convoy effect?

Look at the below table for example : Look at the Non-Preemptive SJF table Suppose if the burst time of process $P_1$ was a very large number compared to $7$, the processes $P_3,P_2$ and $P_4$ have ...
4
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2answers
83 views

Scheduling a tournament with variable game lengths

I want to solve the following scheduling problem: We have $N$ resources and $\binom{N}{2}$ tasks, such that every task requires exactly two resources and every pair of resources is required by exactly ...
2
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2answers
126 views

Heuristic for Tournament Scheduling

I am holding a bi-yearly tournament in my city, for which I want to write a program that gives me (nearly-)optimal pairings, and waiting time. The setup is as follows: ...
2
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1answer
221 views

task scheduling optimization problem

I'm interested in such problem. I have a set of $n$ tasks ${T_i}$ and directed acyclic graph, which nodes correspond to tasks and edges correspond to order of execution two tasks. In other words if I ...
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0answers
96 views

Reduction of specific scheduling problem to show np-completeness

Given a Set K of n tasks, a set T of t possible time-intervalls to schedule any task, and a number k: Is there a schedule for the tasks, such that there are at most k conflicts (time - overlaps) of ...
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1answer
745 views

SCAN and CSCAN algorithms of disk scheduling

I am having hard time understanding the working of SCAN and CSCAN algorithm of disk scheduling.I understood FCFS,Closest Cylinder Next but heard that SCAN resembles elevator mechanism and got confused....
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0answers
45 views

Approximation for fewest incompatibilities in a scheduling algorithm

Suppose you have a task selection algorithm to select the largest subset of tasks that do no overlap. The greedy algorithm that selects tasks based on their finish time will always produce an optimal ...
3
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1answer
158 views

Does a greedy task selection algorithm find a c-approximate solution?

I was told this question may be better suited here. A scheduling problem can be stated as: Given a set $\{(s_i,f_i)\}_{1\le i\le n}\}$ of tasks identified by their start and end times, choose ...
2
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3answers
123 views

Why does lower integer represent higher priority in scheduling literature?

I'm studying Real Time Systems, and in the textbook most of the focus is on scheduling algorithms. (Textbook: Real-Time Systems by Jane W. S. Liu) In the algorithms that involve priorities, it is ...
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0answers
103 views

Solve a basic mutex lock problem while preventing deadlock

I am solving a problem with a bridge, where you have a one way bridge with people coming from each side. To solve this problem while preventing deadlock (two people going opposite directions on the ...
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1answer
53 views

How do you come up with greedy algorithm for deadline scheduling when comparing x_subscript(i) and y_subscript(k)?

So there are two boxing teams, my team A and the opposing team B, each with m boxers. Based on the player's ranking of skill, x_subscript(i) being the ranking for ith boxer for team A and y_subscript(...
3
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1answer
77 views

Offline scheduling fully determined arbitrary jobs in multiprocessor setting

Let $\mathcal{J} = \{J_1,...,J_n\}$ be a set of jobs with each $J_i = [a_i,r_i,d_i]$ where the job becomes available at its arrival time $a_i$, requires $r_i$ execution time and needs to be finished ...
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1answer
118 views

Round-Robin Scheduler - What exactly is the quantum time used for?

Suppose you have three stages for a job: Creation stage = the job gets created Executing stage = the job is executed/served Finishing stage = the job is "marked" as finished. Now, say the quantum ...
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1answer
52 views

top k selection in fixed size priority queue with dynamically changing values [duplicate]

My question is something of a scheduling problem. I'd like to know what algorithm to use to find the top k items in a fixed length queue in which the values of the items change dynamically.basically a ...
2
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0answers
234 views

Job scheduling problem in O(n log n)

There are $n \leq 10^6$ kinds of cake layers, and for each kind we have a machine capable of baking it in one unit of time and nothing more. Now, a cake is a sequence of layers, more specificly a ...