Ammar Peter Kaka

A neural networks approach for cost flow forecasting

Artificial neural networks, which simulate neuronal systems of the brain, are useful methods that have attracted the attention of researchers in many disciplinary areas. They have many advantages over traditional methods in situations where the input-output relationship of the system under study is not explicitly known. This paper investigates the feasibility of using neural networks for predicting the cost flow of construction projects, explains the need for cost flow forecasting, and demonstrates the limitation of the existing models. It then introduces neural networks as an alternative approach to those mathematical and statistical methods. The method used in collecting data and modelling the cost flow is described. Results of the testing are presented and discussed.

Towards automated progress assessment of workpackage components in construction projects using computer vision

Traditional methods of collecting data on the progress of construction projects often involve human judgement, high costs, and are too infrequent to provide managers with timely and accurate control data. This study proposes a system that aims to address some of these shortcomings through automation. Our first contribution is a framework for the automatic generation of work packages. We describe the conceptual model and develop a prototype implementation, based on the results of a survey designed to capture the current practice of formulating work packages as performed in the industry. Our second contribution is a system that employs computer vision (CV) techniques to report on the progress of these work packages automatically. This is achieved by analysing sequences of digital images acquired regularly by on-site cameras. The result of this analysis, when compared with the expected state of construction, provides progress feedback on the work packages, allowing a project to be monitored more effectively.

Estimation of project total cost and duration for housing projects in the U.K.

Abstract There are a number of variables which act individually and in combination to influence project total cost and duration. The extent of the effect of these variables is dependent on the nature of the project. A project is defined in terms of its constituent variables. This paper is concerned with a variety of project definitions within the category of housing projects in the U.K. The most influential variables are examined and, in quantified terms, the extent of the relationship between these variables and project total cost and duration is determined. To this end, two separate models are developed and proposed for the estimation of project cost and duration. While the model for the latter encompasses the former as a variable, the model for the estimation of project cost is independent from project duration.

Development of a company‐level dynamic cash flow forecasting model (DYCAFF)

Current methods of predicting cash flow have a number of significant weaknesses. At the project level, previous models are simple and incorporate only some of the variables affecting cash flow. On the company level, budgeting is performed on an overall basis (i.e. no account is taken of individual contracts). This is mainly due to the fact that a considerable amount of any years turnover is contributed by contracts that have yet to be won (or even known of) at the time of the budget. This approach, in addition to being inaccurate, precludes the role of budgeting as a tool for strategy evaluation. This paper presents a dynamic cash flow forecasting model that would assist contractors to effectively plan and manage the cash flow of individual projects and at a company level. The advances made in the model can be represented by three of its main features. First, the development of a more accurate and complex cash flow calculation mechanism. Second, the development of an information system that will help the contractor enter the data necessary for this mechanism. Third, the development of a company‐level model that is based on individual projects, both known and unknown to the contractor at the time of the forecast.

A novel multiple linear regression model for forecasting S‐curves

Purpose – Cash flow forecasting is an indispensable tool for construction companies, and is essential for the survival of any contractor at all stages of the work. A simple and fast technique of forecasting cash flow accurately is required, considering the short time available and the associated cost. Seeks to examine this issue.Design/methodology/approach – The paper argues that instead of producing an S‐curve that is based on historical projects combined (state‐of‐the‐art is based on classifying projects into groups and producing a standard curve for each group simply by fitting one curve into the historical data), here the attempt is to produce an individual S‐curve for an individual project. A sample of data from 50 projects was collected and 20 criteria were identified to classify these projects. Using the most influential criteria, a multiple linear regression model was created to forecast the programme of works and hence the S‐curves. A further six projects were used to validate and test the model....

Productivity improvements: understand the workforce perceptions of productivity first

Purpose – To establish the differences between the perceptions of white‐collar managers and blue‐collar workers with respect to the factors that affect construction labour productivity, and to show that integrating the differences could lead to productivity improvements.Design/methodology/approach – A questionnaire survey administered to a purposive sample of 400 project managers and a convenience sample of 152 construction workers, eliciting current trends of their perceptions towards 59 factors that were extracted from an extensive literature review and exploratory study. This was followed by the identification of good practice examples from site observations across two project sites.Findings – The study found distinct differences between the two groups, with white‐collar managers being more concerned with resource planning issues and the blue‐collar workers placing more value on the utilisation of resources. Furthermore, the site observations demonstrated that integrating these differences through empl...

Modelling payment mechanisms for supply chain in construction

Purpose – Different direct/indirect managerial and contractual links throughout the supply chain have been researched to improve project performance. These links are undoubtedly influencing payment and cash flow mechanisms. As different members of the supply chains are affected differently by the factors influencing cash flow, payment mechanisms have to be designed in such a way that this uneven sensitivity to cash flow factors is addressed and linked to value and utility. The purpose of this paper is to introduce an IT system developed to model different payment mechanisms to enable the supply chain members to decide on the most appropriate payment mechanism.Design/methodology/approach – The adopted methodology to select the appropriate payment mechanism is first illustrated. The mathematical model is then developed. The IT system to automate the developed methodology is then presented. The system considers alternative payment terms and conditions across the supply chain in a transparent and negotiated m...

An evaluation of contractors’ satisfaction with payment terms influencing construction cash fl ow

Construction cash flow models developed in previous researches demonstrated that cash flow profiles vary for differing procurement methods. However, the issue of whether contractors are satisfied or dissatisfied with payment terms impacting cash flows in differing procurement methods is yet to be investigated. This is the concern of this study. The study identified from literature, payment terms potentially thought to impact construction cash flow. Using a 6‐point Likert‐type scale, a questionnaire survey was administered to UK construction contractors in order to assess their level of satisfaction with identified payment terms influencing construction cash flow. Responses from the survey, which focused on traditional and design and build procurement methods were analysed using mean response analysis and one‐way analysis of variance. Results showed that while contractors were satisfied with most of the contractual factors investigated under both procurement systems, they were dissatisfied with two of the factors, namely, time lag between entitlement to receive and actually receiving cash payment and percentage of contract sum retained. This dissatisfaction calls for action to consider devising alternative means of dealing with retention and delay payments.

The risks of unbalanced bidding

Unbalanced bidding models have largely ignored the risk aspect of item pricing. Many researchers have acknowledged that there are considerable risks associated with unbalancing a bid but little has been done to describe these risks, let alone model them. A new framework is proposed by which all of these risks can be assessed. It identifies that these risks comprise the risk of rejection, the risk of reaction, and the risk of being wrong. It is further proposed that the value‐at‐risk (‘VaR’) method of measuring risk is a convenient way by which to combine all of these risks into one composite assessment. This quantified assessment serves to describe the extent of risk generated by each level of each item’s price. Previous related research has proposed an unbalanced bidding model that has likewise provided a measurement of the expected reward generated by each level of each item’s price. By doing a summation of these, keeping in mind that the prices applied to all of a project’s component items must add up to the overall bid price, the contractor is able to assess both the risks as well as the rewards of all possible item price combinations.

The impact of diversification on the performance of UK construction firms

Built upon theories from outside the construction management literature, this study assesses the impact of product diversification on the performance of construction firms in the UK. Performance was measured based on financial ratios of management performance while diversification was measured by the specialisation ratio. The research involved the use of financial data of construction firms covering the period 1995‐2004. The choice of the period is informed by the economic stability during the period and also, by the fact that diversification is a long‐term strategy. The findings indicate that focused firms outperform both moderately and highly diversified firms based on return on total assets (ROTA) and profit margin (PM). However, no performance difference was found between the moderately diversified and highly diversified firms.