Amir M. Alani

A model for smoothing time-series data in construction

The understanding of the behaviour of time‐series data has been a matter of concern to researchers and practitioners in a variety of fields ranging from social science and economics to engineering. Also, the behaviour of many phenomena within fields relating and peripheral to construction is described as a time series. Typically, the time‐series analysis is carried out in order to forecast the future values of the series. These techniques, however, are also used to abstract the generalities within the series, hence facilitating the replication of the entire profile, reflecting only the main characteristics of the profile. There is a variety of techniques that can be applied to a set of time‐related data. The choice of the technique is, therefore, dependent on the nature of the problem and the characteristics of the data. The diversity of available techniques is, on the one hand an advantage for all analysts. However, this diversity is also an indication that there is no universal technique that is applicable to a diversity of time‐series data. This work fundamentally addresses the issue of smoothing and curve‐fitting techniques rather than predicting and forecasting. A technique is offered which is tested against a set of criteria that are designed to focus on the accuracy of imitation and the practicality of operation: the ability to deal with a large number of time‐series sets of data in a consistent, replicable and automated way. The viability of the technique is demonstrated by its application to expenditure profiles of a large number of construction projects. The size of the sample and the diversity in the profiles of the expenditure patterns provided an appropriate testing ground for the universality of the model. The results indicated that the model can effectively transform a jagged time series into a smooth pattern, while complying with a set of criteria many of which are common to several other research works relating to time‐series data analysis. The proposed technique sequences a number of basic smoothing methods and the process involves the treatment and incorporation of the residual values.

Potential effects of the confirmation bias in house condition surveys

Surveyor variability has a significant impact on the accuracy and reliability of house condition surveys. Reports on one particular cognitive bias that surveyors may use when undertaking house condition surveys – the confirmation bias. Two experiments are conducted to investigate the confirmation bias. The experiments seem to indicate that the confirmation bias does have the potential to have an impact on condition survey decision making and therefore to contribute to surveyor variability. Methods of dealing with the bias are discussed; particularly the potential application of expert systems alongside hand‐held data‐capture devices.

Surveyor variability in educational stock surveys – a lens model study

The importance of survey data accuracy is paramount if school maintenance programs are to be a true reflection of the maintenance needs of that school. Previous research has identified the issue of surveyor variability, i.e. the situation where two or more surveyors, surveying the same building, arrive at very different survey decisions. The research presented in this paper reports on social judgement theory – a model of a surveyor’s judgements where the varying values of surveyors, in terms of the “importance” they give to building elements, can be elicited by using the regression formula. The results of the research can be used to normalise survey data in an attempt to make them more truly reflect the actual condition of a school. The results can also be used to assess training requirements for individual surveyors.

Applications of a developed quantitative model in building repair and maintenance – case study

Describes a case study that applies the principles of “a proposed quantitative model for building repair and maintenance” developed in theory by Alani et al. The proposed model relies on the relationship between the number of defects and time where the collection of the number of defects data has been made using a condition based survey and specifically developed survey form. Using established declining balance depreciation methods a close correlation between the models cost/time and quality/time curves has been determined. Applies the proposed coded system of observing, assessing, recording and appraising the condition of the elements of a large residential building and calculates the cost of repairing and maintaining (at a pre‐determined condition) the elements of that specific building.

Quantitative models for building repair and maintenance: a comparative case‐study

This paper presents a comparative study of three well‐established building maintenance forecasting models in conjunction with a quantitative model which has been developed recently. After a brief introduction of each method, data collected from a large building survey were mapped into four distinctive methods and comparison was carried out in terms of priorities that these four methods adopt for future maintenance work. An analysis of responses to a questionnaire including 100 companies and individuals involved in maintenance and facilities management work (including quantity surveyors’ organisations) revealed that 100 percent of the public sector organisations use maintenance assessment methods for their prioritisation of maintenance management work. It also revealed that 92 percent of the private sector and 95 percent of all the organisations use condition based maintenance assessment methods for the prioritisation of maintenance operations. Results of this questionnaire have been used as introductory material to support the necessity for this piece of research.

Barcombe Roman Villa: An exercise in GPR time slicing and comparative geophysics

Barcombe Roman Villa, a site under threat of destruction from ploughing, has been investigated by use of resistivity, field walking and excavation. GPR survey was added to these techniques and a comparison is made between the composite picture provided by the former and time slices derived from the latter.

Imaging of Scarce Archaeological Remains Using Microwave Tomographic Depictions of Ground Penetrating Radar Data

The Romano-British site of Barcombe in East Sussex, England, has suffered heavy postdepositional attrition through reuse of the building materials for the effects of ploughing. A detailed GPR survey of the site was carried out in 2001, with results, achieved by usual radar data processing, published in 2002. nThe current paper reexamines the GPR data using microwave tomography approach, based on a linear inverse scattering model, and a 3D visualization that permits to improve the definition of the villa plan and reexamine the possibility of detecting earlier prehistoric remains.

Development of an effective methodology for assessment, repair and maintenance of the earthquake damaged buildings

Purpose – Considerable amounts of work have been carried out in developing cost models for the repair and maintenance of earthquake damaged buildings in recent years. Most of these developments have been based on methods and approaches using risk analysis, probabilistic earthquake and scenario earthquakes. The main objectives of this paper can be summarised as: to highlight the extent and variability of influencing factors (quantitative and qualitative) affecting the repair and maintenance of post‐earthquake damage to buildings and structures; and to present the first configuration of a proposed quantitative model for the repair and maintenance of damage inflicted on buildings.Design/methodology/approach – To achieve this, an in‐depth review of the available literature in this field was deemed necessary. The presented literature review, demonstrates the need and the gap in knowledge, as well as the complexity of the subject for such development. In developing the proposed model, attention has been paid to...

A proposed quantitative model for building repair and maintenance - Theory, model development and application

The effective and efficient management of buildings necessitates, amongst other aspects, the ability to interrogate reliable data relating to condition, cost implications of that condition and the spend options available and appropriate. Most buildings have been subject to one or more surveys and data from these is often available to the building owner, manager or user. The form and value of such data is, however, variable in the extreme and is, not least, relevant mainly to the organization or person who commissioned that particular survey. This paper introduces a quantitative model for the repair and maintenance of buildings/properties. It is based on a coded system of observing, assessing, recording and appraising the condition of those elements of a building which would most influence the costs of repairing or maintaining elements of, or the whole of, buildings. Background information and criteria for the development of this model is detailed in this paper and also, the model matrix system defining the step-by-step calculation process of cost of repair and maintenance has been reported. A detailed report on a case-study (application of the model) consisting of the data collection and cost analysis of a property is also provided. The case-study includes a comparison between the predicted cost of repair and the real cost of repair (cost after completion of repair work) concerning a residential dwelling.

Surveyor variability – application of social judgement theory

Surveyor variability has been previously identified as a barrier to the consistency and usability of house condition survey data. This paper explores the use of social judgement theory (SJT) as a potential method to account for, and reduce the impact of, surveyor variability. The study followed the principles of SJT first proposed by Egon Brunswik. The results of the study indicate that the SJT method does have the potential to aid understanding of the survey judgement policy of individual surveyors in terms of the importance they give to building elements and the underlying focus, or theme, of a survey. Knowledge of this policy could be utilised in house condition surveys by recalibration of survey results to take account of a surveyor’s policy. In addition, training requirements for individual surveyors could be identified.