Enhancing Delphi Method with Algorithmic Estimates for Software Effort Estimation: An Experimental Study

Literature review shows that more accurate software effort and cost estimation methods are needed for software project management success. Expert judgment and algorithmic model estimation are two predominant methods discussed in the literature. Both are reported almost at the comparable level of accuracy performance. The combination of the two methods is suggested to increase the estimation accuracy. Delphi method is an encouraging structured expert judgment method for software effort group estimation but surprisingly little was reported in the literature. The objective of this study is to test if the Delphi estimates will be more accurate if the participants in the Delphi process are exposed to the algorithmic estimates. A Delphi experiment where the participants in the Delphi process were exposed to three algorithmic estimates –Function Points, COCOMO estimates, and Use Case Points, was therefore conducted. The findings show that the Delphi estimates are slightly more accurate than the statistical combination of individual expert estimates, but they are not statistically significant. However, the Delphi estimates are statistically significant more accurate than the individual estimates. The results also show that the Delphi estimates are slightly less optimistic than the statistical combination of individual expert estimates but they are not statistically significant either. The adapted Delphi experiment shows a promising technique for improving the software cost estimation accuracy.

CONFIDENCE LIMITS WITH MULTIPLE CHANNELS AND ARBITRARY PROBABILITY DISTRIBUTIONS FOR SENSITIVITY AND EXPECTED BACKGROUND

A MC method is proposed to compute upper limits, in a pure Bayesian approach, when the errors associated to the experimental sensitivity and to the expected background content are not Gaussian distributed or not small enough to apply the usual approximations. It is relatively easy to extend the procedure to the multichannel case (for instance when different decay branchings, or luminosities or experiments have to be combined). Some of the searches for supersymmetric particles performed in the DELPHI experiment at the LEP electron–positron collider use such a procedure to propagate the systematics into the calculation of the cross-section upper limits. One of these searches will be described as an example.

MEASUREMENT OF THE FORWARD-BACKWARD ASYMMETRY OF B AND C QUARK AT THE Z PEAK

The forward-backward asymmetries of the processes [Formula: see text] and [Formula: see text] were measured from a sample of hadronic Z decays collected by the DELPHI experiment between 1993 and 1995. Enriched samples of [Formula: see text] and [Formula: see text] events were obtained using lifetime information. The tagging of b and c quarks in these samples was based on the semileptonic decay channels b/c → X + μ and b/c → X + e combined with the charge flow information in the hemisphere opposite to the lepton. Averaging the results presented in this paper with those already published with 1991 and 1992 DELPHI data sample, the following pole asymmetries were obtained: [Formula: see text]

SEARCH FOR CHARGED HIGGS BOSONS IN E+E- COLLISIONS AT LEP AT THE DELPHI EXPERIMENT

A search for pair produced charged Higgs bosons was performed in the high energy data collected by the DELPHI detector at LEP II at centre-of-mass energies from 183 GeV to 208 GeV. The three different final states, τντν, [Formula: see text] and [Formula: see text] were considered. No excess of data compared to the expected Standard Model processes was observed and the existence of a charged Higgs boson with mass lower than 75.0 GeV / c 2 is excluded at 95% confidence level.

SEARCH FOR STANDARD MODEL HIGGS BOSON AT LEP WITH THE DELPHI DETECTOR

Search for the Higgs boson of the Standard Model have been performed using the data collected by the DELPHI experiment at LEP in 2000 corresponding to centre-of-mass energies up to 209 GeV. These results are used, in combination with our results from previous years, to obtain preliminary confidence levels on the existence of an Standard Model Higgs boson with a mass in the range [105-115] GeV /c2.