scholarly journals USING SOFT PRECEDENCE RELATIONS FOR REDUCTION OF THE CONSTRUCTION PROJECT DURATION

2012 ◽  
Vol 18 (2) ◽  
pp. 262-279 ◽  
Author(s):  
Piotr Jaskowski ◽  
Anna Sobotka
Keyword(s):  
Resource Allocation ◽  
Project Scheduling ◽  
Programming Model ◽  
Mathematical Form ◽  
Practical Application ◽  
Project Duration ◽  
Linear Integer Programming ◽  
Concurrent Execution ◽  
Logical Sequence ◽  
Soft Logic

Current network techniques used for project scheduling presume that there is only one logical sequence of activities. However, in reality, the precedence logic of activities is not necessarily unchangeable. There are two types of relations between activities: fixed (hard) and soft. Current scheduling methods do not differentiate between these two types of relations and require a planner to choose one particular logical sequence based on some assumptions. The paper presents a model that allows for “weakening” the links between activities, i.e. that permits concurrent execution of activities or reversing their order, but this may require additional resource-consuming works or expenditures. The model involves two subtypes of soft logic: REVERSED and CANCELED to represent the soft relations between activities. Its mathematical form is a mixed linear integer programming model of minimizing the project duration without exceeding the allowed budget. The paper presents an example of practical application of the method to scheduling interior finishing works. The results support the argument that using soft logic relations between construction activities provides more flexibility in reducing project duration, activities timing and resource allocation.

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.

Work continuity constraints in repetitive project scheduling considering soft logic

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xin Zou ◽  
Guangchuan Wu ◽  
Qian Zhang
Keyword(s):  
Programming Model ◽  
Mixed Integer ◽  
Future Research ◽  
Small Scale ◽  
Content Type ◽  
Project Duration ◽  
Additional Information ◽  
Work Interruptions ◽  
Conflicting Objectives ◽  
Soft Logic

PurposeRepetitive projects play an important role in the construction industry. A crucial point in scheduling this type of project lies in enabling timely movement of crews from unit to unit so as to minimize the adverse effect of work interruptions on both time and cost. This paper aims to examine a repetitive scheduling problem with work continuity constraints, involving a tradeoff among project duration, work interruptions and total project cost (TPC). To enhance flexibility and practicability, multi-crew execution is considered and the logic relation between units is allowed to be changed arbitrarily. That is, soft logic is considered.Design/methodology/approachThis paper proposes a multi-objective mixed-integer linear programming model with the capability of yielding the optimal tradeoff among three conflicting objectives. An efficient version of the e-constraint algorithm is customized to solve the model. This model is validated based on two case studies involving a small-scale and a practical-scale project, and the influence of using soft logic on project duration and total cost is analyzed via computational experiments.FindingsUsing soft logic provides more flexibility in minimizing project duration, work interruptions and TPC, especial for non-typical projects with a high percentage of non-typical activities.Research limitations/implicationsThe main limitation of the proposed model fails to consider the learning-forgetting phenomenon, which provides space for future research.Practical implicationsThis study assists practitioners in determining the “most preferred” schedule once additional information is provided.Originality/valueThis paper presents a new soft logic-based mathematical programming model to schedule repetitive projects with the goal of optimizing three conflicting objectives simultaneously.

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.

Construction project scheduling by ranked positional weight method

1998 ◽  
Vol 25 (3) ◽  
pp. 424-436 ◽  
Author(s):  
Paul Wing Ming Tam ◽  
Pujitha Bandara Gamagedera Dissanayake
Keyword(s):  
Resource Allocation ◽  
Project Scheduling ◽  
Construction Projects ◽  
Critical Path ◽  
Construction Project ◽  
Critical Path Method ◽  
Bridge Construction ◽  
Project Duration ◽  
Weight Method ◽  
Positional Weight

Construction projects are commonly scheduled by the critical path method or its similar methods, with the assumption that resources are unlimited. The ranked positional weight method, which may be used for project scheduling and resource allocation for both constrained and unconstrained resource scheduling, is found to be relatively easy in application. In construction, the availability of resources is sometimes limited and this leads to an extension of project duration. The critical path method and similar approaches cannot provide an answer in this scenario. A bridge construction project is used to illustrate how the method can be applied.Key words: scheduling, resource allocation, ranked positional weight method.

Resource allocation for robust project scheduling

2011 ◽  
Vol 59 (1) ◽  
pp. 51-55 ◽  
Author(s):  
M. Klimek ◽  
P. Łebkowski
Keyword(s):  
Resource Allocation ◽  
Project Scheduling ◽  
Formal Description ◽  
Resource Allocation Problem ◽  
Flow Network ◽  
Robust Scheduling ◽  
Resource Flow ◽  
Precise Analysis ◽  
The Stability ◽  
Robustness Metrics

Resource allocation for robust project schedulingThe paper presents a formal description of the resource allocation problem for resource-constrained project scheduling. A schedule can be executed by various resource flow networks which may differ in terms of resistance to disruptions occurring during project execution. The authors define such criteria of evaluating a resource flow network which can be more useful than robustness metrics used so far in the research. The authors discuss the importance of robust scheduling for execution projects and propose metrics for resource allocation robustness which take into consideration the stability of the final schedule. Those metrics make it possible to carry out a more precise analysis concerning the properties of the resource flow network in terms of its robustness to disruptions in comparison with a well known flexibility indicator,flex.

A New Decision Support System for Optimal Integrated Project Scheduling and Resource Planning

2021 ◽  
pp. 1367-1383
Author(s):  
Amir Ahrari ◽  
Ali Haghani
Keyword(s):  
Resource Allocation ◽  
Project Scheduling ◽  
Efficient Solution ◽  
Practical Problem ◽  
Mathematical Formulation ◽  
Optimal Solution ◽  
Resource Planning ◽  
Scheduling Problems ◽  
Activity Scheduling ◽  
Integrated Project

Two scheduling practices are commonly used depending on the availability of resources. When resources are not expensive, activities are scheduled and then resources are allocated until the available resources are exhausted. Then, iterative adjustments are applied to the resource allocation plan and the activities sequence to reach a feasible solution. Conversely, when expensive resources are involved, a resource allocation plan based on the economics of the resource is established and then activities are scheduled accordingly. However, Resource Constrained Scheduling Problems (RCSP) are not solved efficiently with either of these approaches. To find the optimal solution, activity scheduling and resource allocation should be formulated as an integrated optimization problem. Such models become numerically cumbersome for practical size problems and difficult to solve. In this article, a novel mathematical formulation and an efficient solution algorithm are proposed for solving RCSPs. Then, this framework is used for solving a practical problem in the context of the construction industry.

Sign in / Sign up

Export Citation Format

Share Document