Ali Fares, Ashraf Elazouni, Sameh Al-Shihabi and Mubarak Al-Alawi
In the construction industry, cash flow issues can impact both contractors and owners. Although finance-based scheduling (FBS) models were developed to control contractors’ cash…
Abstract
Purpose
In the construction industry, cash flow issues can impact both contractors and owners. Although finance-based scheduling (FBS) models were developed to control contractors’ cash flow, researchers completely disregarded cash flow management for owners’ portfolios. Therefore, FBS is once again introduced in this study from the perspective of the owners of portfolios.
Design/methodology/approach
For the FBS problem of portfolio owners (FBS-PO), a mixed integer linear program (MILP) model is developed. The purpose is to ensure that owners’ cash inflows are greater than cash outflows while minimizing the sum of weighted extensions of the projects in portfolios. Owing to the difficulties encountered in solving the proposed MILP model, genetic algorithm (GA) and particle swarm optimization (PSO) meta-heuristics are used. To ensure the feasibility of the solutions, a special serial schedule generation heuristic was developed in conjunction with the random key method for chromosome representation.
Findings
The GA produced higher-quality solutions compared to PSO, though it required more processing time. The GA has proven to be a far better choice than the MILP exact solver for bigger portfolios. Additionally, there is a linear correlation between the number of activities in portfolios and the amount of computational time required for the GA to converge.
Originality/value
This paper introduces the new research domain of FBS from the owners’ perspective (FBS-PO). In order to establish the FBS-PO as a stand-alone domain, a critical review of the FBS studies in the literature was conducted. In addition, the goals, characteristics, implementation and challenges of the FBS heuristics are benchmarked against those of the special serial schedule generation heuristic developed for the FBS-PO problem.
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Keywords
Ashraf Elazouni, Anas Alghazi and Shokri Z. Selim
The purpose of this paper is to compare the performance of the genetic algorithm (GA), simulate annealing (SA) and shuffled frog-leaping algorithm (SFLA) in solving discrete…
Abstract
Purpose
The purpose of this paper is to compare the performance of the genetic algorithm (GA), simulate annealing (SA) and shuffled frog-leaping algorithm (SFLA) in solving discrete versus continuous-variable optimization problems of the finance-based scheduling. This involves the minimization of the project duration and consequently the time-related cost components of construction contractors including overheads, finance costs and delay penalties.
Design/methodology/approach
The meta-heuristics of the GA, SA and SFLA have been implemented to solve non-deterministic polynomial-time hard (NP-hard) finance-based scheduling problem employing the objective of minimizing the project duration. The traditional problem of generating unfeasible solutions in scheduling problems is adequately tackled in the implementations of the meta-heuristics in this paper.
Findings
The obtained results indicated that the SA outperformed the SFLA and GA in terms of the quality of solutions as well as the computational cost based on the small-size networks of 30 activities, whereas it exhibited the least total duration based on the large-size networks of 120 and 210 activities after prolonged processing time.
Research limitations/implications
From researchers’ perspective, finance-based scheduling is one of the few domain problems which can be formulated as discrete and continuous-variable optimization problems and, thus, can be used by researchers as a test bed to give more insight into the performance of new developments of meta-heuristics in solving discrete and continuous-variable optimization problems.
Practical implications
Finance-based scheduling discrete-variable optimization problem is of high relevance to the practitioners, as it allows schedulers to devise finance-feasible schedules of minimum duration. The minimization of project duration is focal for the minimization of time-related cost components of construction contractors including overheads, finance costs and delay penalties. Moreover, planning for the expedient project completion is a major time-management aspect of construction contractors towards the achievement of the objective of client satisfaction through the expedient delivery of the completed project for clients to start reaping the anticipated benefits.
Social implications
Planning for the expedient project completion is a major time-management aspect of construction contractors towards the achievement of the objective of client satisfaction.
Originality/value
SFLA represents a relatively recent meta-heuristic that proved to be promising, based on its limited number of applications in the literature. This paper is to implement SFLA to solve the discrete-variable optimization problem of the finance-based scheduling and assess its performance by comparing its results against those of the GA and SA.
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Ovad Kima, Alon Urlainis, Kun-Chi Wang and Igal M. Shohet
This research aims to enhance understanding of the safety climate within small and medium-sized construction enterprises (SMEs). By conducting an in-depth analysis of safety…
Abstract
Purpose
This research aims to enhance understanding of the safety climate within small and medium-sized construction enterprises (SMEs). By conducting an in-depth analysis of safety practices and management approaches in this sector, it identifies critical gaps and provides actionable recommendations to improve the safety climate in construction SMEs.
Design/methodology/approach
An integrated method approach was employed, integrating quantitative and qualitative elements. A fishbone diagram model was developed to categorize key safety factors into four categories: Workers, Equipment, Management and Environment. Based on these categories, core safety parameters for SMEs were derived. A 42-question survey was developed and distributed to foremen across various construction sites in Eilat, Israel, aiming to capture diverse safety practices and illuminate the specific safety practices within these SMEs.
Findings
Key findings underscore variability in safety management practices across different sites, emphasizing management’s role and the prioritization of equipment and environment in safety protocols. The study revealed a strong correlation between higher safety scores and reduced accident rates, highlighting the efficacy of robust safety management. The research also correlates financial investment in safety with improved outcomes yet stresses the importance of strategic resource deployment, particularly in settings with limited resources. Additionally, inconsistencies in near-miss reporting were identified, suggesting the need for standardization to leverage these incidents for safety enhancement.
Research limitations/implications
The research has certain limitations, including its narrow geographical focus on the city of Eilat, situated in a southern and arid region that presents specific climate challenges. Another limitation is the relatively small sample size, consisting of 20 sites. However, it is important to note that the significance of the findings has been rigorously assessed using test statistics, which have yielded satisfactory levels of significance.
Practical implications
The research establishes a practical framework for the development, management and maintenance of a safety climate in construction SMEs. Clear leading indicators are defined, enabling construction SMEs to cultivate a sustainable safety climate, enhance safety measures and prevent work accidents.
Social implications
The research presents a comprehensive theoretical and practical framework for establishing, managing and controlling the safety climate in construction SMEs. It introduces leading indicators as effective tools for enhancing the safety climate in SMEs, offering a robust framework for cultivating a sustainable safety environment at both the site and company levels.
Originality/value
This study provides valuable insights into the safety climate of construction SMEs, offering a foundation for targeted improvements and informing future research directions in construction safety management. This analysis highlights SMEs' unique challenges and practices, providing valuable perspectives for enhancing safety in this critical construction industry sector.