scholarly journals Discrete-continuous project scheduling with preemptable activities

2016 ◽  
Vol 64 (2) ◽  
pp. 383-393 ◽  
Author(s):  
R. Różycki ◽  
G. Waligóra ◽  
J. Węglarz
Keyword(s):  
Project Scheduling ◽  
Resource Constraints ◽  
Future Research ◽  
Scheduling Problems ◽  
Feasible Schedule ◽  
Project Duration ◽  
Processing Rate ◽  
Rate Functions ◽  
Continuous Resources ◽  
Increasing Function

Abstract In this paper, discrete-continuous project scheduling problems with preemptable activities are considered. In these problems, activities of a project simultaneously require discrete and continuous resources for their execution. The activities are preemptable, and the processing rate of each activity is a continuous, increasing function of the amount of a single continuous resource allotted to the activity at a time. The problem is to find a precedence- and discrete resource-feasible schedule and, simultaneously, continuous resource allocation that would minimize the project duration. Convex and concave processing rate functions are considered separately. We show that for convex functions the problem is simple, whereas for concave functions a special methodology has to be developed. We discuss the methodology for three cases of the problem: no discrete resource constraints, one discrete resource being a set of parallel, identical machines, and an arbitrary number of discrete resources. In each case we analyze separately independent and precedence-related activities. Some conclusions and directions for future research are given.

Using a Sliding-Frame Approach for Scheduling Large and Complex IT Projects

2011 ◽  
Vol 2 (4) ◽  
pp. 1-13 ◽  
Author(s):  
Yuval Cohen ◽  
Ofer Zwikael ◽  
Arik Sadeh
Keyword(s):  
Project Scheduling ◽  
Resource Constraints ◽  
Project Planning ◽  
Rolling Horizon ◽  
Scheduling Problems ◽  
It Projects ◽  
Software Projects ◽  
Project Duration ◽  
Software Companies ◽  
Planning And Management

Many IT projects and software development projects are very complex and sophisticated involving a large coordinated team. Such projects are a constant part of the operations of software companies such as Microsoft, SAP, Oracle, Google, Yahoo, IBM, and others. Many other companies carry large software projects as part of their IT operations. As a result of the size and complexity of such projects, a rolling horizon approach for their planning and management is not only plausible but also desirable. For large projects, traditional project scheduling techniques cannot provide an optimal and timely solution to minimum project duration under precedence and resource constraints. This paper proposes a technique that allows utilizing non-polynomial (NP) algorithms in a heuristic manner – generating high quality schedules in reasonable time. This approach can be applied efficiently for solving most project scheduling problems. The main advantage of this approach is its ability to dissect the original problem into small sub-problems of a controllable size to which exact techniques can be applied. Thus, it neutralizes the complexity of the applied algorithms (and their non-polynomial growth). Moreover, the same technique could be used for implementing a rolling-horizon approach in project planning and management.

Scheduling Large and Complex IT Projects Using Sliding-Frame Approach

2014 ◽  
pp. 1521-1533
Author(s):  
Yuval Cohen ◽  
Arik Sadeh ◽  
Ofer Zwikael
Keyword(s):  
Project Scheduling ◽  
Resource Constraints ◽  
Project Planning ◽  
Rolling Horizon ◽  
Scheduling Problems ◽  
It Projects ◽  
Software Projects ◽  
Project Duration ◽  
Software Companies ◽  
Planning And Management

Many IT projects and software development projects are very complex and sophisticated involving a large coordinated team. Such projects are a constant part of the operations of software companies such as Microsoft, SAP, Oracle, Google, Yahoo, IBM, and others. Many other companies carry large software projects as part of their IT operations. As a result of the size and complexity of such projects, a rolling horizon approach for their planning and management is not only plausible but also desirable. For large projects, traditional project scheduling techniques cannot provide an optimal and timely solution to minimum project duration under precedence and resource constraints. This paper proposes a technique that allows utilizing non-polynomial (NP) algorithms in a heuristic manner – generating high quality schedules in reasonable time. This approach can be applied efficiently for solving most project scheduling problems. The main advantage of this approach is its ability to dissect the original problem into small sub-problems of a controllable size to which exact techniques can be applied. Thus, it neutralizes the complexity of the applied algorithms (and their non-polynomial growth). Moreover, the same technique could be used for implementing a rolling-horizon approach in project planning and management.

Scheduling Large and Complex IT Projects Using Sliding-Frame Approach

2012 ◽  
pp. 173-185
Author(s):  
Yuval Cohen ◽  
Arik Sadeh ◽  
Ofer Zwikael
Keyword(s):  
Project Scheduling ◽  
Resource Constraints ◽  
Project Planning ◽  
Rolling Horizon ◽  
Scheduling Problems ◽  
It Projects ◽  
Software Projects ◽  
Project Duration ◽  
Software Companies ◽  
Planning And Management

Many IT projects and software development projects are very complex and sophisticated involving a large coordinated team. Such projects are a constant part of the operations of software companies such as Microsoft, SAP, Oracle, Google, Yahoo, IBM, and others. Many other companies carry large software projects as part of their IT operations. As a result of the size and complexity of such projects, a rolling horizon approach for their planning and management is not only plausible but also desirable. For large projects, traditional project scheduling techniques cannot provide an optimal and timely solution to minimum project duration under precedence and resource constraints. This paper proposes a technique that allows utilizing non-polynomial (NP) algorithms in a heuristic manner – generating high quality schedules in reasonable time. This approach can be applied efficiently for solving most project scheduling problems. The main advantage of this approach is its ability to dissect the original problem into small sub-problems of a controllable size to which exact techniques can be applied. Thus, it neutralizes the complexity of the applied algorithms (and their non-polynomial growth). Moreover, the same technique could be used for implementing a rolling-horizon approach in project planning and management.

Construction Multi-Project Scheduling Model Considering Different Resource Allocation Behavior

2012 ◽  
Vol 174-177 ◽  
pp. 2815-2819 ◽  
Author(s):  
Shu Shun Liu ◽  
Wei Tong Chen
Keyword(s):  
Resource Allocation ◽  
Project Scheduling ◽  
Resource Constraints ◽  
Programming Model ◽  
Scheduling Problems ◽  
Resource Assignment ◽  
Allocation Mechanism ◽  
Allocation Policy ◽  
Project Duration ◽  
Project Environment

According to previous researches, an investigation through small to mid-size construction contractors showed that 84% of construction contractors execute their projects in a multi-project environment. In a multi-project environment, scheduling problems with resource constraints are much more complicated than those in a single project. One of the most important factors that influence multi-project scheduling problems is resource allocation policy, depending on the types of resources, which can be defined by the way of resource acquisition and sharing behavior. This paper discusses resource allocation mechanism for construction multi-project scheduling issues, and then presents an optimization-based model to resolve resource allocation problems. This research developed a CP-based (Constraint Programming) model, which is capable of handling different optimization objectives such as minimizing total cost, overall project duration, subject to resource assignment combinations for each activity. Based on research results, the influence of different types of resource quantity on multi-project duration is discussed. Moreover, resource competitive behavior among all projects is recognized. It concludes that the effective increment of critical resources can reduce overall project duration. The major goal of this research is to find the relation among duration-cost-resource in a multi-project environment, and provide systematic information for construction parties when making resource allocation decisions.

scholarly journals On some implementations of solving the resource constrained project scheduling problems

2019 ◽  
Vol 29 (1) ◽  
pp. 31-42 ◽  
Author(s):  
E.Kh. Gimadi ◽  
E.N. Goncharov ◽  
D.V. Mishin
Keyword(s):  
Renewable Resources ◽  
Project Scheduling ◽  
Resource Constraints ◽  
Scheduling Problems ◽  
Makespan Minimization ◽  
Resource Constrained ◽  
Resource Constrained Project Scheduling ◽  
Project Scheduling Problem ◽  
Technological Constraints

We consider a resource-constrained project scheduling problem with respect to the makespan minimization criterion. The problem accounts for technological constraints of activities precedence together with resource constraints. Activities pre- emptions are not allowed. The problem with renewable resources is NP-hard in the strong sense. We propose an exact branch and bound algorithm for solving the problem with renewable resources. It uses our new branching scheme based on the representation of a schedule in form of the activity list. We use two approaches of constructing the lower bound. We present results of numerical experiments, illustrating the quality of the proposed lower bounds. The test instances are taken from the library of test instances PSPLIB.

An Improved Production Scheduling Algorithm Based on Resource Constraints

2013 ◽  
Vol 455 ◽  
pp. 619-624
Author(s):  
Yan Gao ◽  
Xin Zhang ◽  
Jian Zhong Xu
Keyword(s):  
Production Scheduling ◽  
Resource Constraints ◽  
Critical Path ◽  
Constraint Satisfaction Problem ◽  
Scheduling Algorithm ◽  
Mathematics Model ◽  
Scheduling Problems ◽  
Project Duration ◽  
Aircraft Assembly ◽  
Two Stages

For resource-constrained project scheduling problems, with aircraft assembly as its background, we established its mathematics model as constraint satisfaction problem. An improved critical path scheduling algorithm is proposed, considering the constraints of precedence relations, resource constraints and space constraints, through the two stages of planning, reaching for aircraft assembly task scheduling optimization objectives. Through the given numerical example results show that, when the objective consists in minimizing the project duration, the algorithm has better performance.

scholarly journals Comparison of Heuristic Priority Rules in the Solution of the Resource-Constrained Project Scheduling Problem

2021 ◽  
Vol 13 (17) ◽  
pp. 9956
Author(s):  
Osman Hürol Türkakın ◽  
David Arditi ◽  
Ekrem Manisalı
Keyword(s):  
Resource Allocation ◽  
Project Scheduling ◽  
Resource Constraints ◽  
Priority Rules ◽  
Resource Constrained ◽  
Start Time ◽  
Project Duration ◽  
Resource Constrained Project Scheduling ◽  
Finish Time ◽  
Positional Weight

Resource-constrained project scheduling (RCPS) aims to minimize project duration under limited resource availabilities. The heuristic methods that are often used to solve the RCPS problem make use of different priority rules. The comparative merits of different priority rules have not been discussed in the literature in sufficient detail. This study is a response to this research gap. It compares 17 heuristic priority rules and seeks the best performing heuristic priority rule. This is the first study ever that compares heuristic priority rules by considering combinations of variations in (1) resource allocation procedures, (2) number of activities, (3) number of resource constraints, and (4) resource supply levels. The objective is to understand the relative merits of heuristic rules used in solving the RCPS problem. The findings indicate that the “minimum late finish time” rule generates the shortest predicted project duration when used in parallel resource allocation, whereas the “minimum late start time”, “minimum late finish time”, and the “highest rank of positional weight 2” rules perform best in serial resource allocation. It was also found that parallel resource allocation is slightly superior to serial resource allocation in most instances.

scholarly journals Compact MDDs for Pseudo-Boolean Constraints with At-Most-One Relations in Resource-Constrained Scheduling Problems

2017 ◽  
Author(s):  
Miquel Bofill ◽  
Jordi Coll ◽  
Josep Suy ◽  
Mateu Villaret
Keyword(s):  
Project Scheduling ◽  
Resource Constraints ◽  
Time Dependent ◽  
Scheduling Problems ◽  
Resource Constrained ◽  
Binary Decision ◽  
Compact Binary ◽  
Order Of Magnitude ◽  
Project Scheduling Problem ◽  
Multi Mode

Pseudo-Boolean (PB) constraints are usually encoded into Boolean clauses using compact Binary Decision Diagram (BDD) representations. Although these constraints appear in many problems, they are particularly useful for representing resource constraints in scheduling problems. Sometimes, the Boolean variables in the PB constraints have implicit at-most-one relations. In this work we introduce a way to take advantage of these implicit relations to obtain a compact Multi-Decision Diagram (MDD) representation for those PB constraints. We provide empirical evidence of the usefulness of this technique for some Resource-Constrained Project Scheduling Problem (RCPSP) variants, namely the Multi-Mode RCPSP (MRCPSP) and the RCPSP with Time-Dependent Resource Capacities and Requests (RCPSP/t). The size reduction of the representation of the PB constraints lets us decrease the number of Boolean variables in the encodings by one order of magnitude. We close/certify the optimum of many instances of these problems.

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