Current software cost estimation models, such as the 1981 Constructive Cost Model (COCOMO) for software cost estimation and its 1987 Ada COCOMO update, have been experiencing increasing difficulties in estimating the costs of software developed to new life cycle processes and capabilities. These include non-sequential and rapid-development process models; reuse-driven approaches involving commercial off-the*shelf (COTS) packages, re-engineering, applications composition, and applications generation capabilities; object-oriented approaches supported by distributed middleware; and software process maturity initiatives. This paper summarizes research in deriving a baseline COCOMO 2.0 model tailored to these new forms of software development, including rationale for the model decisions. The major new modeling capabilities of COCOMO 2.0 are a tailorable family of software sizing models, involving Object Points, Function Points, and Source Lines of Code; nonlinear models for software reuse and re-engineering; an exponentdriver approach for modeling relative software diseconomies of scale; and several additions, deletions and updates to previous COCOMO effort-multiplier cost drivers. This model is serving as a framework for an extensive current data collection and analysis effort to further refine and calibrate the model's estimation capabilities.

During the 10-year period (1980 to 1989), 76 patients with hepatocellular carcinoma (HCC) were treated by subtotal hepatic resection (HX) and 105 patients by orthotopic liver transplantation (TX) under cyclosporine-steroid therapy. Overall 1- to 5-year survival rates of the HX group were 71.1%, 55.0%, 47.2%, 37.2%, and 32.9%, respectively, and those of the TX group were 65.7%, 49.0%, 39.2%, 35.6%, and 35.6%, respectively. The survival rates after HX and after TX correlated well with pTNM stages and were similar in each stage between the two groups. However, when HCC was associated with cirrhosis of the liver, the survival rates after TX were significantly better than those after HX at each stage of pTNM classification. The tumor-recurrence rate was high both after HX (50%) and TX (43%), particularly in advanced stages of pTNM classification (60% or more). Twelve patients after HX and 13 patients after TX lived more than 5 years during this 10-year period. Fibrolamellar HCC and early stages of HCC were highly represented among the long-term survivors. Further improvement in survival rates depends on nonsurgical anti-cancer therapy before and/or after surgical removal of HCC.

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