Testing the value of best value:Evidence from educational facilities projects

Contractor selection is one of the most important step in ensuring the success of any construction project. Failing to adequately select the winning contractor may lead to problems in the project delivery phase such as bad quality and delay in the expected project duration; which ultimately results in cost overruns. This paper presents an approach by which a what-if scenario can be analysed in educational facilities projects in the UK; therefore if the client selected the best value contractor for a project whose submitted price is not the lowest price, a what-if scenario was conducted to show how the lowest priced contractor would have fared had he/she been awarded the contract instead. This was done by analysing historic data of projects that have selected the lowest priced contractor. Then correlations were derived between variables; which was then be inputted into a Monte Carlo Simulation to analyse 3 real educational facilities projects that used a best value selection method. Using Monte Carlo Simulation allowed us to see all the possible outcomes of cost, and duration. It was concluded that selecting the best value contractor in educational facilities projects may not be necessary in terms of cost

A quantifiable method of assessing the risk of selecting the lowest bidder in construction projects:A literature review

Contractor selection is an important step in ensuring the success of any construction project. Failing to adequately select the winning contractor may lead to problems in the project delivery phase such as bad quality and delay in the expected project duration; which ultimately results in cost overruns. This paper reviewed the strength of existing studies on the link between contractor selection strategy and project outcomes, with a view of proposing an approach on how one might try to examine this relationship moving forward. There are research that try to establish a direct relationship between contractor selection strategy and the outcome of the construction project. There are also decision support tools such as AHP or ANP that help clients prioritise various factors when selecting contractors. However the majority of these research and tools are informed by self-perception questionnaires and surveys that makes it difficult to gauge the strength of the relationship between contractor selection and project outcomes. In other words, there are hardly any empirical research that tries to establish this relationship. Literature review on the sources of cost overruns did not entirely reveal contractor selection as a main source of cost overrun; although from the explanations given for causes of cost overruns, one would be able to see how wrong contractor selection does play a part. Literature review on the various approaches to contractor selection on the other hand, did little to show the effect of contractor selection on the outcome of construction projects. Hence, the future direction of the research is to help clients see choosing a particular contractor selection strategy; whether lowest bid, or best value, affects the outcome of a construction project: cost and duration

Spatial aspects of MRSA epidemiology:A case study using stochastic simulation, kernel estimation and SaTScan

The identification of disease clusters in space or space-time is of vital importance for public health policy and action. In the case of methicillin-resistant Staphylococcus aureus (MRSA), it is particularly important to distinguish between community and health care-associated infections, and to identify reservoirs of infection. 832 cases of MRSA in the West Midlands (UK) were tested for clustering and evidence of community transmission, after being geo-located to the centroids of UK unit postcodes (postal areas roughly equivalent to Zip+4 zip code areas). An age-stratified analysis was also carried out at the coarser spatial resolution of UK Census Output Areas. Stochastic simulation and kernel density estimation were combined to identify significant local clusters of MRSA (p<0.025), which were supported by SaTScan spatial and spatio-temporal scan. In order to investigate local sampling effort, a spatial 'random labelling' approach was used, with MRSA as cases and MSSA (methicillin-sensitive S. aureus) as controls. Heavy sampling in general was a response to MRSA outbreaks, which in turn appeared to be associated with medical care environments. The significance of clusters identified by kernel estimation was independently supported by information on the locations and client groups of nursing homes, and by preliminary molecular typing of isolates. In the absence of occupational/ lifestyle data on patients, the assumption was made that an individual's location and consequent risk is adequately represented by their residential postcode. The problems of this assumption are discussed, with recommendations for future data collection

Computations and Measurements of the Magnetic Polarizability Tensor Characterisation of Highly Conducting and Magnetic Objects

PurposeThe ability to characterise highly conducting objects, that may also be highly magnetic, by the complex symmetric rank–2 magnetic polarizability tensor (MPT) is important for metal detection applications including discriminating between threat and non-threat objects in security screening, identifying unexploded anti-personnel landmines and ordnance and identifying metals of high commercial value in scrap sorting. Many everyday non-threat items have both a large electrical conductivity and a magnetic behaviour, which, for sufficiently weak fields and the frequencies of interest, can be modelled by a high relative magnetic permeability. This paper aims to discuss the aforementioned idea.Design/methodology/approachThe numerical simulation of the MPT for everyday non-threat highly conducting magnetic objects over a broad range of frequencies is challenging due to the resulting thin skin depths. The authors address this by employing higher order edge finite element discretisations based on unstructured meshes of tetrahedral elements with the addition of thin layers of prismatic elements. Furthermore, computer aided design (CAD) geometrical models of the non-threat and threat object are often not available and, instead, the authors extract the geometrical features of an object from an imaging procedure.FindingsThe authors obtain accurate numerical MPT characterisations that are in close agreement with experimental measurements for realistic physical objects. The assessment of uncertainty shows the impact of geometrical and material parameter uncertainties on the computational results.Originality/valueThe authors present novel computations and measurements of MPT characterisations of realistic objects made of magnetic materials. A novel assessment of uncertainty in the numerical predictions of MPT characterisations for uncertain geometry and material parameters is included

Establishing a link between contractor selection strategy and project outcomes: A simulation study

Perceived benefits of the best value strategy and the problems the lowest price strategy has caused in the construction industry; has led to the increase in the use of the best value strategy in selecting contractors. Whilst there is research that have tried to establish a direct relationship between a contractor selection strategy and the project outcomes, there are hardly any empirical research that tries to establish this relationship. This paper presents a quantifiable method of assessing the risk of selecting different contractor selection strategies using educational facilities projects in the UK. A Monte-Carlo simulation study was conducted to assess how the lowest priced contractor would have fared against the best value contractor had it been awarded the contract instead. It was concluded that selecting the best value contractor in educational facilities projects is not necessary in terms of cost. Furthermore, though the results are limited to educational facilities projects, the method can be adapted to other sectors

Land resource requirements for bioenergy in India

This study presents a two stage process to determine suitable areas to grow fuel crops: i) FAO Agro Ecological Zones (AEZ) procedure is applied to four Indian states of different geographical characteristics; and ii) Modelling the growth of candidate crops with GEPIC water and nutrient model, which is used to determine potential yield of candidate crops in areas where irrigation water is brackish or soil is saline. Absence of digital soil maps, paucity of readily available climate data and knowledge of detailed requirements of candidate crops are some of the major problems, of which, a series of detailed maps will evaluate true potential of biofuels in India

The correction of commercial IMU data for single image registration

This study aims to enhance the accuracy of the commercial Inertial Measurement Unit (IMU) developed using the advanced Micro-Electro-Mechanical System (MEMS) by using the epoch analysis technique. The epoch analysis approach has been established to quantify the observation data from static measurement stations. A statistical approach is used to: 1) eliminate gross errors; 2) determine the appropriate data (filter); 3) estimate future values; and 4) for data evaluation. The main attribute of epoch analysis is its treatment of redundancy in the observed data by taking into account the frequencies that are found within it. In a dynamic application, epoch analysis is used by examining the instantaneous position. In this paper, the competency of epoch analysis in reducing the commercial IMU data for geometrical image correction is presented

A Physically-Based Model of Heterogeneous Hillslopes I. Runoff Production.

A fully three-dimensional model of variably saturated flow on a hillslope has been used to explore the effects of different random patterns of saturated hydraulic conductivity on a 150 m by 100 m hillslope. Both surface and subsurface runoff production are simulated. The model's simulations suggest that peak discharges and runoff volumes are generally increased by the presence of heterogeneity, increasing with increasing variance and spatial dependence of the underlying random field. Simulations using different realizations with the same random field parameters show that for the case of soils showing no dependence, differences in runoff production between realizations are small at this scale of hillslope. The differences increase with increasing spatial dependence, particularly for the case of low-conductivity soils producing surface runoff

A Physically-Based Model of Heterogeneous Hillslopes II. Effective Hydraulic Conductivities.

Using the results of a fully three-dimensional model of variably saturated flow on a heterogeneous hillslope, the concept of equivalent homogeneous hillslopes is explored. By considering single realizations of random patterns of saturated hydraulic conductivity, attempts are made to determine single effective hydraulic conductivity values capable of reproducing both subsurface and surface flow hydrographs. For the case of high-permeability soils, effective parameters were found to reasonably reproduce the hillslope hydrograph, although there was no consistent relationship between the effective values and the moments of the spatial distributions. For the case of low-permeability soils, characterized by surface flow domination of the runoff hydrograph, single effective parameters were not found to be capable of reproducing both subsurface and surface flow responses. Furthermore, the event dependency of effective conductivity values under such conditions was demonstrated