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21 – 30 of over 1000
Article
Publication date: 7 October 2013

Osama Moselhi and Nazila Roofigari-Esfahan

This paper aims to present a new method to circumvent the limitations of current schedule compression methods which reduce schedule crashing to the traditional time-cost trade-off…

1968

Abstract

Purpose

This paper aims to present a new method to circumvent the limitations of current schedule compression methods which reduce schedule crashing to the traditional time-cost trade-off analysis, where only cost is considered.

Design/methodology/approach

The schedule compression process is modeled as a multi-attributed decision making problem in which different factors contribute to priority setting for activity crashing. For this purpose, a modified format of the Multiple Binary Decision Method (MBDM) along with iterative crashing process is utilized. The method is implemented in MATLAB, with a dynamic link to MS-Project to facilitate the needed iterative rescheduling. To demonstrate the use of the developed method and to present its capabilities, a numerical example drawn from literature was analysed.

Findings

When considering cost only, the generated results were in good agreement with those generated using the harmony search (HS) method, particularly in capturing the project least-cost duration. However, when other factors in addition to cost were considered, as expected, different project least-cost and associated durations were obtained.

Research limitations/implications

The developed method is not applicable, in its present formulation, to what is known as “linear projects” such as construction of highways and pipeline infrastructure projects which exhibit high degree of repetitive construction.

Originality/value

The novelty of the developed method lies in its capacity to allow for the consideration of a number of factors in addition to cost in performing schedule compression. Also through its allowance for possible variations in the relative importance of these factors at the individual activity level, it provides contractors with flexibility to consider a number of compression execution plans and identifies the most suitable plan. Accordingly, it enables the integration of contractors' judgment and experience in the crashing process and permits consideration of different project environments and constraints.

Article
Publication date: 11 November 2019

Marimuthu Kannimuthu, Benny Raphael, Palaneeswaran Ekambaram and Ananthanarayanan Kuppuswamy

Construction firms keep minimal resources to maintain productive working capital. Hence, resources are constrained and have to be shared among multiple projects in an…

Abstract

Purpose

Construction firms keep minimal resources to maintain productive working capital. Hence, resources are constrained and have to be shared among multiple projects in an organization. Optimal allocation of resources is a key challenge in such situations. Several approaches and heuristics have been proposed for this task. The purpose of this paper is to compare two approaches for multi-mode resource-constrained project scheduling in a multi-project environment. These are the single-project approach (portfolio optimization) and the multi-project approach (each project is optimized individually, and then heuristic rules are used to satisfy the portfolio constraint).

Design/methodology/approach

A direct search algorithm called Probabilistic Global Search Lausanne is used for schedule optimization. Multiple solutions are generated that achieve different trade-offs among the three criteria, namely, time, cost and quality. Good compromise solutions among these are identified using a multi-criteria decision making method, Relaxed Restricted Pareto Version 4. The solutions obtained using the single-project and multi-project approaches are compared in order to evaluate their advantages and disadvantages. Data from two sources are used for the evaluation: modified multi-mode resource-constrained project scheduling problem data sets from the project scheduling problem library (PSPLIB) and three real case study projects in India.

Findings

Computational results prove the superiority of the single-project approach over heuristic priority rules (multi-project approach). The single-project approach identifies better solutions compared to the multi-project approach. However, the multi-project approach involves fewer optimization variables and is faster in execution.

Research limitations/implications

It is feasible to adopt the single-project approach in practice; realistic resource constraints can be incorporated in a multi-objective optimization formulation; and good compromise solutions that achieve acceptable trade-offs among the conflicting objectives can be identified.

Originality/value

An integer programming model was developed in this research to optimize the multiple objectives in a multi-project environment considering explicit resource constraints and maximum daily costs constraints. This model was used to compare the performance of the two multi-project environment approaches. Unlike existing work in this area, the model used to predict the quality of activity execution modes is based on data collected from real construction projects.

Details

Engineering, Construction and Architectural Management, vol. 27 no. 4
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 19 October 2020

Sayyid Ali Banihashemi and Mohammad Khalilzadeh

The purpose of this paper is to evaluate project activities' efficiency in different execution modes for the optimization of time–cost-quality and environmental impacts trade-off…

752

Abstract

Purpose

The purpose of this paper is to evaluate project activities' efficiency in different execution modes for the optimization of time–cost-quality and environmental impacts trade-off problem.

Design/methodology/approach

This paper presents a parallel Data Envelopment Analysis (DEA) method for evaluation of project activities with different execution modes to select the best execution mode and find a trade-off between objectives. Also, according to the nature of the project activities, outputs are categorized into desirable (quality) and undesirable (time, cost and environmental impacts) and analyzed based on the DEA model. In order to rank efficient execution modes, the ideal and anti-ideal virtual units method is used. The proposed model is implemented on a real case of a rural water supply construction project to demonstrate its validity.

Findings

The findings show that the use of the efficient execution mode in each activity leads to an optimal trade-off between the four project objectives (time, cost, quality and environmental impacts).

Practical implications

This study help project managers and practitioners with choosing the most efficient execution modes of project activities taking time–cost-quality-environmental impacts into account.

Originality/value

In this paper, in addition to time and cost optimization of construction projects, quality factors and environmental impacts are considered. Further to the authors' knowledge, there is no method for evaluating project activities' efficiency. The efficiency of different activity modes is also evaluated for the first time to select the most efficient modes. This research can assist project managers with choosing the most appropriate execution modes for the activities to ultimately accomplish the project with the lowest time, cost and environmental impacts along with the highest quality.

Article
Publication date: 16 March 2021

Xin Zou, Lihui Zhang and Qian Zhang

The purpose of this research is to develop a time-cost optimization model to schedule repetitive projects while considering limited resource availability.

Abstract

Purpose

The purpose of this research is to develop a time-cost optimization model to schedule repetitive projects while considering limited resource availability.

Design/methodology/approach

The model is based on the constraint programming (CP) framework; it integrates multiple scheduling characteristics of repetitive activities such as continuous or fragmented execution, atypical activities and coexistence of different modes in an activity. To improve project performance while avoiding inefficient hiring and firing conditions, the strategy of bidirectional acceleration is presented and implemented, which requires keeping regular changes in the execution modes between successive subactivities in the same activity.

Findings

Two case studies involving a real residential building construction project and a hotel refurbishing project are used to demonstrate the application of the proposed model based on four different scenarios. The results show that (1) the CP model has great advantages in terms of solving speed and solution quality than its equivalent mathematical model, (2) higher project performance can be obtained compared to using previously developed models and (3) the model can be easily replicated or even modified to enable multicrew implementation.

Originality/value

The original contribution of this research is presenting a novel CP-based repetitive scheduling optimization model to solve the multimode resource-constrained time-cost tradeoff problem of repetitive projects. The model has the capability of minimizing the project total cost that is composed of direct costs, indirect costs, early completion incentives and late completion penalties.

Details

Engineering, Construction and Architectural Management, vol. 29 no. 2
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 1 April 1993

Jurgen Maximov and Hendrik Gottschlich

Observes the success of Japanese companies and industries andattempts to analyse the reasons behind such success and to identify thestrategic success factors. Lists the three…

Abstract

Observes the success of Japanese companies and industries and attempts to analyse the reasons behind such success and to identify the strategic success factors. Lists the three determining factors for the attainment of competitive advantage as: time; cost; and quality, and shows how each of these has been exploited in full by Japanese companies. Uses the examples of Wal Mart (USA) and Ito‐Yokado (Japan) to illustrate how these factors can be translated successfully into retailing.

Details

International Journal of Retail & Distribution Management, vol. 21 no. 4
Type: Research Article
ISSN: 0959-0552

Keywords

Article
Publication date: 29 May 2023

Peipei Wang, Kun Wang, Yunhan Huang and Peter Fenn

Time-cost trade-off is normal conduct in construction projects when projects are expectedly late for delivery. Existing research on time-cost trade-off strategic management mostly…

Abstract

Purpose

Time-cost trade-off is normal conduct in construction projects when projects are expectedly late for delivery. Existing research on time-cost trade-off strategic management mostly focused on the technical calculation towards the optimal combination of activities to be accelerated, while the managerial aspects are mostly neglected. This paper aims to understand the managerial efforts necessary to prepare construction projects ready for an upcoming trade-off implementation.

Design/methodology/approach

A preliminary list of critical factors was first identified from the literature and verified by a Delphi survey. Quantitative data was then collected by a questionnaire survey to first shortlist the preliminary factors and quantify the predictive model with different machine learning algorithms, i.e. k-nearest neighbours (kNN), radial basis function (RBF), multiplayer perceptron (MLP), multinomial logistic regression (MLR), naïve Bayes classifier (NBC) and Bayesian belief networks (BBNs).

Findings

The model's independent variable importance ranking revealed that the top challenges faced were the realism of contractual obligation, contractor planning and control and client management and monitoring. Among the tested machine learning algorithms, multilayer perceptron was demonstrated to be the most suitable in this case. This model accuracy reached 96.5% with the training dataset and 95.6% with an independent test dataset and could be used as the contingency approach for time-cost trade-offs.

Originality/value

The identified factor list contributed to the theoretical explanation of the failed implementation in general and practical managerial improvement to better avoid such failure. In addition, the established predictive model provided an ad-hoc early warning and diagnostic tool to better ensure time-cost implementation success.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 18 July 2019

Rok Cajzek and Uroš Klanšek

The purpose of this paper is cost optimization of project schedules under constrained resources and alternative production processes (APPs).

Abstract

Purpose

The purpose of this paper is cost optimization of project schedules under constrained resources and alternative production processes (APPs).

Design/methodology/approach

The model contains a cost objective function, generalized precedence relationship constraints, activity duration and start time constraints, lag/lead time constraints, execution mode (EM) constraints, project duration constraints, working time unit assignment constraints and resource constraints. The mixed-integer nonlinear programming (MINLP) superstructure of discrete solutions covers time–cost–resource options related to various EMs for project activities as well as variants for production process implementation.

Findings

The proposed model provides the exact optimal output data for project management, such as network diagrams, Gantt charts, histograms and S-curves. In contrast to classic scheduling approaches, here the optimal project structure is obtained as a model-endogenous decision. The project planner is thus enabled to achieve optimization of the production process simultaneously with resource-constrained scheduling of activities in discrete time units and at a minimum total cost.

Practical implications

A set of application examples are addressed on an actual construction project to display the advantages of proposed model.

Originality/value

The unique value this paper contributes to the body of knowledge reflects through the proposed MINLP model, which is capable of performing the exact cost optimization of production process (where presence and number of activities including their mutual relations are dealt as feasible alternatives, meaning not as fixed parameters) simultaneously with the associated resource-constrained project scheduling, whereby that is achieved within a uniform procedure.

Details

Engineering, Construction and Architectural Management, vol. 26 no. 10
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 8 June 2021

Moaaz Elkabalawy and Osama Moselhi

This paper aims to present an integrated method for optimized project duration and costs, considering the size and cost of crews assigned to project activities' execution modes.

430

Abstract

Purpose

This paper aims to present an integrated method for optimized project duration and costs, considering the size and cost of crews assigned to project activities' execution modes.

Design/methodology/approach

The proposed method utilizes fuzzy set theory (FSs) for modeling uncertainties associated with activities' duration and cost and genetic algorithm (GA) for optimizing project schedule. The method has four main modules that support two optimization methods: modeling uncertainty and defuzzification module; scheduling module; cost calculations module; and decision-support module. The first optimization method uses the elitist non-dominated sorting genetic algorithm (NSGA-II), while the second uses a dynamic weighted optimization genetic algorithm. The developed scheduling and optimization methods are coded in python as a stand-alone automated computerized tool to facilitate the developed method's application.

Findings

The developed method is applied to a numerical example to demonstrate its use and illustrate its capabilities. The method was validated using a multi-layered comparative analysis that involves performance evaluation, statistical comparisons and stability evaluation. Results indicated that NSGA-II outperformed the weighted optimization method, resulting in a better global optimum solution, which avoided local minima entrapment. Moreover, the developed method was constructed under a deterministic scenario to evaluate its performance in finding optimal solutions against the previously developed literature methods. Results showed the developed method's superiority in finding a better optimal set of solutions in a reasonable processing time.

Originality/value

The novelty of the proposed method lies in its capacity to consider resource planning and project scheduling under uncertainty simultaneously while accounting for activity splitting.

Details

Engineering, Construction and Architectural Management, vol. 29 no. 5
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 24 January 2022

Samin Mahdavian, Ming Lu and Estacio Pereira

Previous research regarding shaping factors and major causes behind accidents in the construction field is reviewed. In particular, a hypothetical model is established to…

Abstract

Purpose

Previous research regarding shaping factors and major causes behind accidents in the construction field is reviewed. In particular, a hypothetical model is established to correlate activity time, cost and safety in the context of construction activity acceleration planning. Two demonstration cases are presented to illustrate the proposed theoretical model in the context of critical activity expedition planning. Further, a third case uses a 100-activity project to perform the global level total project time and cost analysis, identifying specific activity acceleration plans that would materialize the shortened total project time at the lowest total project cost.

Design/methodology/approach

This research proposes a safety-centric application framework to guide construction acceleration planning at both activity and project levels while taking sufficient preventive measures against safety hazards and accidents. As planning construction acceleration by factoring in safety constraints inevitably drives up cost, it is imperative to control increases in activity costs at the local level in connection with schedule acceleration planning while at the same time not compromising on safety. This research also addresses this critical question through performing global level total project time and cost analysis.

Findings

An application framework is proposed for guiding a planner through identifying accident shaping factors, obeying schedule acceleration rules and accounting for safety-related costs in attempts to mitigate hazardous situations on-site at both activity level (local) and project level (global), resulting in (1) minimizing the increase of total project cost in schedule acceleration while at the same time not compromising on safety at individual activities; (2) producing specific execution plans on each individual activity in terms of the amount of time to crash and the associated activity cost.

Originality/value

This study is original in developing theories and methods for evaluating the impact of safety constraints upon construction time and cost in activity acceleration planning and project time-cost analysis. The research fills a gap in knowledge in terms of how to factor in sufficient safety constraints while achieving project time and cost objectives on construction acceleration planning at both activity and project levels.

Details

Engineering, Construction and Architectural Management, vol. 30 no. 4
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 11 February 2019

S.M. Reza Alavipour and David Arditi

Planning for increased contractor profits should start at the time the contract is signed because low profits and lack of profitability are the primary causes of contractor…

Abstract

Purpose

Planning for increased contractor profits should start at the time the contract is signed because low profits and lack of profitability are the primary causes of contractor failure. The purpose of this paper is to propose an integrated profit maximization model (IPMM) that aims for maximum expected profit by using time-cost tradeoff analysis, adjusted start times of activities, minimized financing cost and minimized extension of work schedule beyond the contract duration. This kind of integrated approach was never researched in the past.

Design/methodology/approach

IPMM is programmed into an automated system using MATLAB 2016a. It generates an optimal work schedule that leads to maximum profit by means of time-cost tradeoff analysis considering different activity acceleration/deceleration methods and adjusting the start/finish times of activities. While doing so, IPMM minimizes the contractor’s financing cost by considering combinations of different financing alternatives such as short-term loans, long-term loans and lines of credit. IPMM also considers the impact of extending the project duration on project profit.

Findings

IPMM is tested for different project durations, for the optimality of the solutions, differing activity start/finish times and project financing alternatives. In all cases, contractors can achieve maximum profit by using IPMM.

Research limitations/implications

IPMM considers a deterministic project schedule, whereas stochastic time-cost tradeoff analysis can improve its performance. Resource allocation and resource leveling are not considered in IPMM, but can be incorporated into the model in future research. Finally, the long computational time is a challenge that needs to be overcome in future research.

Practical implications

IPMM is likely to increase profits and improve the chances of contractors to survive and grow compared to their competitors. The practical value of IPMM is that any contractor can and should use IPMM since all the data required to run IPMM is available to the contractor at the time the contract is signed. The contractor who provides information about network logic, schedule data, cost data, contractual terms, and available financing alternatives and their APRs can use an automated IPMM that adjusts activity start times and durations, minimizes financing cost, eliminates or minimizes time extensions, minimizes total cost and maximizes expected profit.

Originality/value

Unlike any prior study that looks into contractors’ profits by considering the impact of only one or two factors at a time, this study presents an IPMM that considers all major factors that affect profits, namely, time-cost tradeoff analysis, adjusted start times of activities, minimized financing cost and minimized extension of work schedule beyond the contract duration.

Details

Engineering, Construction and Architectural Management, vol. 26 no. 1
Type: Research Article
ISSN: 0969-9988

Keywords

21 – 30 of over 1000