A Survey on Usage and Diffusion of Project Risk Management Techniques and Software Tools in the Construction Industry

The area of Project Risk Management (PRM) has been extensively researched, and the utilization of various tools and techniques for managing risk in several industries has been sufficiently reported. Formal and systematic PRM practices have been made available for the construction industry. Based on such body of knowledge, this paper tries to find out the global picture of PRM practices and approaches with the help of a survey to look into the usage of PRM techniques and diffusion of software tools, their level of maturity, and their usefulness in the construction sector. Results show that, despite existing techniques and tools, their usage is limited: software tools are used only by a minority of respondents and their cost is one of the largest hurdles in adoption. Finally, the paper provides some important guidelines for future research regarding quantitative risk analysis techniques and suggestions for PRM software tools development and improvemen

M4-18: The planetary nebula and its WC10 central star

We present a detailed analysis of the planetary nebula M4-18 (G146.7+07.6) and its WC10-type Wolf-Rayet central star, based on high quality optical spectroscopy (WHT/UES, INT/IDS, WIYN/DensPak) and imaging (HST/WFPC2). From a non-LTE model atmosphere analysis of the stellar spectrum, we derive Teff=31kK, log(Mdot/(Msun yr))=-6.05, v_inf=160 km/s and abundance number ratios of H/He<0.5, C/He=0.60 and O/He=0.10. These parameters are remarkably similar to He2-113 ([WC10]). Assuming an identical stellar mass to that determined by De Marco et al. for He2-113, we obtain a distance of 6.8kpc to M4-18 (E(B-V)=0.55mag from nebular and stellar techniques). This implies that the planetary nebula of M4-18 has a dynamical age of 3100 years, in contrast to >270 years for He2-113. This is supported by the much higher electron density of the latter. These observations may only be reconciled with evolutionary predictions if [WC]-type stars exhibit a range in stellar masses. Photo-ionization modelling of M4-18 is carried out using our stellar WR flux distribution, together with blackbody and Kurucz energy distributions obtained from Zanstra analyses. We conclude that the ionizing energy distribution from the Wolf-Rayet model provides the best consistency with the observed nebular properties, although discrepancies remain.Comment: 12 pages, 9 figures, accepted for MNRAS (latex uses mn.sty

Assessing Value for Money in PFI Projects: A Comparative Study of Practices in the UK and Italy

The Value for Money assessment is a critical process in procuring a Private Finance Initiative and it requires accurate ex-ante performance measurement methodologies. The British Government has set new requirements for evaluating VFM through a new assessment model composed of three main stages, namely: programme level assessment, project level assessment, and procurement level assessment. The objective of the new model for VFM assessment is to change the costly, inflexible and opaque side of PFIs in order to deliver cost-effective and improve the quality of public service provision. A theoretical analysis of the implementation of PFI shows the UK as the leading user of this procurement in Europe and Italy is the second. However, there is a disparity in the manner PFI is actually implemented in these two countries and especially how VFM is assessed. Aiming at underlying the best practices of this evaluation process for the most achievable VFM, this paper presents the new VFM assessment model of the UK and a suggestion for its potential application to the Italian PFI procurement process to improve outcomes therei

Two examples of non strictly convex large deviations

We present two examples of a large deviations principle where the rate function is not strictly convex. This is motivated by a model used in mathematical finance (the Heston model), and adds a new item to the zoology of non strictly convex large deviations. For one of these examples, we show that the rate function of the Cramer-type of large deviations coincides with that of the Freidlin-Wentzell when contraction principles are applied.Comment: 11 page