Browsing by Author "Russell, AD"

Now showing 1 - 4 of 4

item: Article-Full-text
Analytical approach for economic risk quantification of large engineering projects
(Taylor and Francis, 1992) Russell, AD; Ranasinghe, M
A consistent,four moment based approach for quantifying time and economic risks is presented. The goal is to produce a computationally efficient tool that can be used to explore economic feasibility and tradeoffs between cost and time performance versus risk as a function of various strategies for executing and sequencing major work packages. A three level hierarchy of parameters is used, starting with time, cost and revenue performance at the work package/revenue stream level to rate of return at the overall project level. Use of a four moment approach and Pearson distributions at all levels of the hierarchy permit the formulation of a consistent and readily automated approach to risk measurement. Treatment of correlations is included. A modified form of PNET is presented for quantifying time uncertainty. Use of limiting values (0, 1) of the PNET transitional correlation provide bounds for decision parameters.
item: Article-Full-text
Analytical approach for economic risk quantification of large engineering projects: validation
(Taylor and Francis, 1992) Ranasinghe, M; Russell, AD
Validation and the computational efficiency of an analytical alternative to Monte Carlo simulation for quantifying risks in project performance measures such as time, cost, net present value and internal rate of return are explored in this paper. The analytical approach is based on the use of the Pearson family of distributions, a four moment characterization of uncertainty for input and output variables and a modified version of the PNET algorithm for modelling time uncertainty. The approach is applied to a generalized hierarchical description of a project's economic structure. Results show that the analytical approach can duplicate results of a full-scale Monte Carlo simulation with approximately 0.033 of the computational effort
item: Article-Full-text
Decision framework for fast-track construction: a deterministic analysis
(1991) Russell, AD; Ranasinghe, M
A deterministic analysis framework that permits the computation of an upper bound on the constant dollar expenditure that should be made to fast-track a project to achieve a specified duration is presented. It employs a baseline plan which corresponds to the traditional method of sequential design, construct, commission and operate, and the economic principle that one will continue to spend as long as the return on the incremental investment equals or exceeds the minimum attractive rate of return. The analysis is based on a generalized definition of fast-track construction, which includes ouerlapping of the construction and revenue phases and acceleration as well as overlapping of design and construction. An example is giuen to illustrate application of the framework.
item: Article-Full-text
Elicitation of subjective probabilities for economic risk analysis: an investigation
(Taylor and Francis, 1993) Ranasinghe, M.; Russell, AD
This paper investigates three major issues regarding the elicitation of expert knowledge for economic risk analysis: (1) recognition of some of the implicit assumptions and beliefs; (2) development of an approach to elicit expert knowledge as accurate, calibrated and coherent subjective probabilities; and (3)a study to explore human ability to predict future events and the validity of the implicit assumptions and beliefs in the context of the expert judgements. The proposed elicitation approach combines the theoretical requirements for valid subjective probabilities with a practical process. The recognition that some of the implicit assumptions and beliefs in engineering risk analysis should be explored when dealing with the human ability to predict future events, and the inherent difficulties in developing experiments and methods to test such beliefs arc some of the benefits of the study. Directions for future work are suggested.