On the Latest Times and Float Times of Activities in a Fuzzy Project Network with LR Fuzzy Numbers

2012 ◽  
Vol 2 (2) ◽  
pp. 91-101 ◽  
Author(s):  
V. Sireesha ◽  
N. Ravi Shankar ◽  
K. Srinivasa Rao ◽  
P. Phani Bushan Rao
Keyword(s):  
Project Scheduling ◽  
Fuzzy Numbers ◽  
Critical Path ◽  
Real Life ◽  
New Method ◽  
Scheduling Problem ◽  
Forward Pass ◽  
Project Scheduling Problem ◽  
Project Network ◽  
Activity Times

In this paper, the authors propose a new method to compute the fuzzy latest times and float times of activities for a project scheduling problem with fuzzy activity times. The authors have considered LR fuzzy numbers to represent the activity times. As the data of the problem are LR fuzzy numbers, the authors have shown that the results are also in terms of LR fuzzy numbers. Total float time of each activity can be found by this method without using the forward pass and backward pass computations. The authors use an example to illustrate the method. This paper shows the advantages of this method over the existing methods with great clarity. The proposed method illustrates its application to fuzzy critical path problems occurring in real life situations.

A Resource-Constrained Project Scheduling Problem with Fuzzy Activity Times

2016 ◽  
Vol 5 (4) ◽  
pp. 1-15 ◽  
Author(s):  
Hossein Zoulfaghari ◽  
Javad Nematian ◽  
Amir Abbas Kanani Nezhad
Keyword(s):  
Project Scheduling ◽  
Solution Method ◽  
Fuzzy Numbers ◽  
Programming Model ◽  
Benchmark Problems ◽  
Scheduling Problem ◽  
Resource Constrained ◽  
Resource Constrained Project Scheduling ◽  
Project Scheduling Problem ◽  
Activity Times

This paper is about the Resource-Constrained Project Scheduling Problem) RCPSP) which is one of the most important problems in last three decades and many researchers have paid attention to it and have reached useful results. In this paper, to cope with uncertainty issue, the RCPSP is studied under fuzzy environment where activity times are assumed to be fuzzy numbers. For this problem with fuzzy numbers as activity times, a linear mathematical programming model is presented. The objective function of the model is minimizing the completion time of project. Since the activity times are fuzzy numbers, finish time is also a fuzzy number. Hence, the model is transformed to a crisp multi-objective linear programming model. To illustrate the solution method, a numerical example is solved under both fuzzy and crisp environment and the results are compared. To prove the efficiency of the proposed method the results of the proposed solution method, some benchmark problems obtained from PSPLIB are utilized.

scholarly journals Solving the nuclear dismantling project scheduling problem by combining mixed-integer and constraint programming techniques and metaheuristics

2021 ◽  
Author(s):  
Felix Hübner ◽  
Patrick Gerhards ◽  
Christian Stürck ◽  
Rebekka Volk
Keyword(s):  
Constraint Programming ◽  
Project Scheduling ◽  
Computational Study ◽  
Real Life ◽  
Mixed Integer ◽  
Extensive Literature ◽  
Scheduling Problem ◽  
Multiple Modes ◽  
Project Scheduling Problem ◽  
Optimisation Techniques

AbstractScheduling of megaprojects is very challenging because of typical characteristics, such as expected long project durations, many activities with multiple modes, scarce resources, and investment decisions. Furthermore, each megaproject has additional specific characteristics to be considered. Since the number of nuclear dismantling projects is expected to increase considerably worldwide in the coming decades, we use this type of megaproject as an application case in this paper. Therefore, we consider the specific characteristics of constrained renewable and non-renewable resources, multiple modes, precedence relations with and without no-wait condition, and a cost minimisation objective. To reliably plan at minimum costs considering all relevant characteristics, scheduling methods can be applied. But the extensive literature review conducted did not reveal a scheduling method considering the special characteristics of nuclear dismantling projects. Consequently, we introduce a novel scheduling problem referred to as the nuclear dismantling project scheduling problem. Furthermore, we developed and implemented an effective metaheuristic to obtain feasible schedules for projects with about 300 activities. We tested our approach with real-life data of three different nuclear dismantling projects in Germany. On average, it took less than a second to find an initial feasible solution for our samples. This solution could be further improved using metaheuristic procedures and exact optimisation techniques such as mixed-integer programming and constraint programming. The computational study shows that utilising exact optimisation techniques is beneficial compared to standard metaheuristics. The main result is the development of an initial solution finding procedure and an adaptive large neighbourhood search with iterative destroy and recreate operations that is competitive with state-of-the-art methods of related problems. The described problem and findings can be transferred to other megaprojects.

scholarly journals Effective Project Scheduling Under Workspace Congestion and Workflow Disturbance Factors

2014 ◽  
Vol 2 (1) ◽  
pp. 35 ◽  
Author(s):  
Vitaly Semenov ◽  
Anton Anichkin ◽  
Sergey Morozov ◽  
Oleg Tarlapan ◽  
Vladislav Zolotov
Keyword(s):  
Project Scheduling ◽  
Construction Projects ◽  
Critical Path ◽  
Resource Utilisation ◽  
Scheduling Problem ◽  
Priority Rules ◽  
Planning And Scheduling ◽  
Advanced Planning ◽  
Project Scheduling Problem ◽  
Spatio Temporal

Effective project management implies the use of advanced planning and scheduling methods that allow to determine feasible sequences of activities and to complete a project on time and on budget. Traditional scheduling tools like fundamental Critical Path Method (CPM) and various methods for Resource Constrained Project Scheduling Problem (RCPSP) and Time Constrained Project Scheduling Problem (TCPSP) have many shortcomings for construction projects where spatial factor plays a critically important role. Previous attempts to interpret space as a specific resource were successful for particular problems of line-of-balance scheduling, space scheduling, dynamic layout planning, horizontal and vertical logic scheduling, workspace congestion mitigating, scheduling multiple projects with movable resources, spatial scheduling of repeated and grouped activities and motion planning. However, none of these methods considers the spatio-temporal requirements in a holistic framework of generic RCPSP problem and provides feasible results accounting for workspace and workflow factors. In this paper we start with the classical RCPSP statement and then present mathematically strong formalisation of the extended generalised problem, taking into account workspace congestion and workflow disturbance constraints specified in practically meaningful and computationally constructive ways. For the generalised RCPSP problem an effective scheduling method is proposed. The method tends to minimise the project makespan while satisfying timing constraints and precedence relations, not exceeding resource utilisation limits, avoiding workspace congestions and keeping workflows continuous. The method reuses so-called serial scheduling scheme and provides for additional computational routines and heuristic priority rules to generate feasible schedules satisfying all the imposed requirements. Advantages of the method and prospects for its application to industrial needs are outlined in the paper too.

scholarly journals On Fuzzy Critical Path Method Based On Ranking Of Various Type-2 Fuzzy Quantities Using Centroid Of Centroids

2019 ◽  
Vol 8 (6) ◽  
pp. 910-920
Keyword(s):  
Path Analysis ◽  
Explicit Form ◽  
Fuzzy Numbers ◽  
Critical Path ◽  
Simple Approach ◽  
Membership Functions ◽  
Project Network ◽  
Generalized Type ◽  
Activity Times

This paper proposes a simple approach to critical path analysis in a project network with activity times being intervals and which are converted into various Type-2 fuzzy quantities. The idea is based on generalized type-2 trapezoidal, hexagonal and octagonal fuzzy numbers and its ranking. The explicit form of membership functions of the type-2 fuzzy activity times is not required in the proposed approach. Moreover, the method is very simple and the numerical example is given for demonstrating and comparing the proposed approach with generalized type-2 trapezoidal, hexagonal and octagonal fuzzy numbers through proposed ranking function.

scholarly journals Constraint Programming-Based Transformation Approach for a Multi-Objective & Multi-Mode Resource Investment Project Scheduling Problem Under Mixed Fuzzy-Stochastic Uncertainties

2021 ◽  
Author(s):  
Kemal Subulan ◽  
Gizem Çakır
Keyword(s):  
Constraint Programming ◽  
Project Scheduling ◽  
Real Life ◽  
Investment Project ◽  
Scheduling Problem ◽  
Multi Objective ◽  
Resource Investment ◽  
Transformation Approach ◽  
Project Scheduling Problem ◽  
Multi Mode

Abstract In fuzzy mathematical programming literature, most of the transformation approaches were mainly focused on integer linear programs (ILPs) with fuzzy parameters/variables. However, these ILP-based solution approaches may be inadequate for solving large-scaled combinatorial fuzzy optimization problems, like project scheduling under fuzzy-stochastic environments. Moreover, many project scheduling applications may contain different types of uncertainties such as fuzziness, stochasticity, dynamism etc. simultaneously in real-life settings. Based on these motivations, this paper presents a novel constraint programming (CP) based transformation approach for solving a multi-objective and multi-mode fuzzy-stochastic resource investment project scheduling problem (FS-MRIPSP) which is a well-known NP-complete problem. In fact, the proposed solution approach mainly depends on a bound & decomposition principle which divides fuzzy components of the problem into crisp middle, lower and upper level problems. Thus, it reduces the problem dimension and does not need to use any standard fuzzy arithmetic and ranking operations directly. Furthermore, stochastic nature of the problem is also taken into account by using a multi-scenario based stochastic programming technique. Finally, a weighted additive fuzzy goal program (WAFGP) is embedded into the proposed CP-based transformation approach in order to produce compromise fuzzy project schedules which trade-off between the expected values of project makespan and total resource usage costs. To show validity and practicality of the proposed approach, a real-life application is also presented for a production-and-operations management (POM) module implementation process of an international Enterprise Resource Planning (ERP) software. The generated fuzzy project schedules under different scenarios by the proposed CP-based approach are also compared to the results of a similar ILP-based transformation approach. Computational results have shown that the proposed CP-based approach outperforms than the ILP-based approach in terms of both solution quality and computational time.

Preemptive multi-skilled resource constrained project scheduling problem with hard/soft interval due dates

2019 ◽  
Vol 53 (5) ◽  
pp. 1877-1898
Author(s):  
Hamidreza Maghsoudlou ◽  
Behrouz Afshar-Nadjafi ◽  
Seyed Taghi Akhavan Niaki
Keyword(s):  
Project Scheduling ◽  
Real Life ◽  
Scheduling Problem ◽  
Due Dates ◽  
Resource Constrained ◽  
Due Date ◽  
Setup Cost ◽  
Resource Constrained Project Scheduling ◽  
Processing Cost ◽  
Project Scheduling Problem

This paper considers a preemptive multi-skilled resource constrained project scheduling problem in a just-in-time environment where each activity has an interval due date to be completed. In this problem setting, resuming a preempted activity requires an extra setup cost, while each time unit violation from the given due date incurs earliness or tardiness penalty. Also, processing cost of each skill to execute any activity depends on the assigned staff member to accomplish the skill. The objective function of the model aims to minimize the total cost of allocating staff to skills, earliness–tardiness penalties and preemption costs. Two integer formulations are proposed for the model which are compared in terms of number of variables, constraints and elapsed run-time to optimality. Furthermore, an ant colony based metaheuristic is developed to tackle real life scales of the proposed model. This algorithm relies on two intelligent local search heuristics. Parameters of the algorithm are calibrated using Taguchi method. The results of the experiments for the proposed algorithm confirm that the proposed algorithm has satisfying performance.

A New Genetic Algorithm for the RCPSP in Large Scale

2013 ◽  
Vol 4 (2) ◽  
pp. 29-40 ◽  
Author(s):  
Hossein Zoulfaghari ◽  
Javad Nematian ◽  
Nader Mahmoudi ◽  
Mehdi Khodabandeh
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Project Scheduling ◽  
Large Scale ◽  
Resource Constraints ◽  
Research Area ◽  
New Method ◽  
Scheduling Problem ◽  
Academic Problem ◽  
Project Scheduling Problem

The Resource Constrained Project Scheduling Problem (RCPSP) is a well-studied academic problem that has been shown to be well suited to optimization via Genetic Algorithms (GA). In this paper, a new method will be designed that would be able to solve RCPSP. This research area is very common in industry especially when a set of activities needs to be finished as soon as possible subject to two sets of constraints, precedence constraints and resource constraints. The presented algorithm in this paper is used to solve large scale RCPSP and improves solutions. Finally, for comparing, results are reported for the most famous classical problems that are taken from PSPLIB.

A Critical Chain Project Scheduling Problem with Multi-Mode

2011 ◽  
Vol 697-698 ◽  
pp. 541-545
Author(s):  
Wu Liang Peng ◽  
Q.J. Jiao
Keyword(s):  
Project Scheduling ◽  
Single Mode ◽  
Scheduling Problem ◽  
Priority Rules ◽  
Application Range ◽  
Decision Level ◽  
Project Scheduling Problem ◽  
Project Network ◽  
Critical Chain ◽  
Multi Mode

Critical chain method (CCM) is a new project method which combines project network technologies and management arts. Although there are lots of researches on it, the existing critical chain method has some drawbacks limiting its decision level in practical application. To improve the decision level and application range of critical chain method, the critical chain method with multi-mode is studied. The project network technology is the foundation of project scheduling problem. All the existing project management tools can only support single mode project network, that is, all the project activities have only one executive mode. We study the multi-mode project network as the foundation of multi-mode CC. Furthermore, by relating multi-mode project network to critical chain method, the critical chain method with multi-mode is presented, and the implementation procedure is proposed. In the implementation of multi-mode CCM, the activity priority rules and mode priority rules are investigated.

scholarly journals A MATHEMATICAL MODEL FOR DYNAMIC PROJECT SCHEDULING PROBLEM AND REACTIVE SCHEDULING IMPLEMENTATION

2020 ◽  
Vol 8 (4) ◽  
pp. 83-97
Author(s):  
Murat RUHLUSARAÇ ◽  
Filiz ÇALIŞKAN
Keyword(s):  
Project Scheduling ◽  
Resource Constraints ◽  
Programming Model ◽  
Real Life ◽  
Dynamic Environment ◽  
Mixed Integer ◽  
Scheduling Problem ◽  
Baseline Schedule ◽  
Dynamic Events ◽  
Project Scheduling Problem

In today's real-life implementations, projects are executed under uncertainty in a dynamic environment. In addition to resource constraints, the baseline schedule is affected due to the unpredictability of the dynamic environment. Uncertainty-based dynamic events experienced during project execution may change the baseline schedule partially or substantially and require projects' rescheduling. In this study, a mixed-integer linear programming model is proposed for the dynamic resource-constrained project scheduling problem. Three dynamic situation scenarios are solved with the proposed model, including machine breakdown, worker sickness, and electricity power cut. Finally, generated reactive schedules are completed later than the baseline schedule.

scholarly journals Branch and Bound Algorithms for Resource Constrained Project Scheduling Problem Subject to Nonrenewable Resources with Prescheduled Procurement

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
A. Shirzadeh Chaleshtarti ◽  
S. Shadrokh ◽  
Y. Fathi
Keyword(s):  
Branch And Bound ◽  
Project Scheduling ◽  
Real Life ◽  
Scheduling Problem ◽  
Nonrenewable Resources ◽  
Resource Constrained ◽  
Resource Constrained Project Scheduling ◽  
Branch And Bound Algorithms ◽  
Project Scheduling Problem ◽  
The Difference

A lot of projects in real life are subject to some kinds of nonrenewable resources that are not exactly similar to the type defined in the project scheduling literature. The difference stems from the fact that, in those projects, contrary to the common assumption in the project scheduling literature, nonrenewable resources are not available in full amount at the beginning of the project, but they are procured along the project horizon. In this paper, we study this different type of nonrenewable resources. To that end, we extend the resource constrained project scheduling problem (RCPSP) by this resource type (RCPSP-NR) and customize four basic branch and bound algorithms of RCPSP for it, including precedence tree, extension alternatives, minimal delaying alternatives, and minimal forbidden sets. Several bounding and fathoming rules are introduced to the algorithms to shorten the enumeration process. We perform comprehensive experimental analysis using the four customized algorithms and also CPLEX solver.

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