Hierarchical holographic modeling for software acquisition risk assessment and management.

摘要

This dissertation addresses the assessment and management of risks associated with the software acquisition processes from a holistic perspective using hierarchical holographic modeling (HHM). The multiple visions and perspectives within which the life cycle of software acquisition is stated and modeled, provide a comprehensive framework for risk assessment and management of software acquisition. In particular, widely used models in software acquisition such as the COCOMO model, can now be extended to incorporate probabilistic as well as dynamic dimensions. The ultimate contributions of this dissertation can be found in at least two major areas: (a) in the theoretical and methodological domain of systems modeling in the quest of a more quantitative risk assessment and management framework, and (b) in advancing the state of practice in the assessment and management of software acquisition by extending highly used models in practice to incorporate more realistic probabilities and dynamic dimensions.; A probabilistic, multiobjective approach to software estimation that focuses on the risk of extreme events and utilizes the conditional expected value as an additional risk management decision-making metric is developed. Motivated by the software community's transition towards a prototype or spiral development process paradigm, a dynamic software estimation model is developed that is particularly suited for modern software development processes. The dynamic model permits analysis of the impact of management control policies on future decision opportunities, while accounting for changes over time in the development environment and the system requirements. A software estimation updating scheme is developed as an extension of the dynamic software estimation model to account for the differences between actual project resource requirements and the estimates of those requirements, and to update the overall resource requirement projections.; The HHM framework is extended to formulate software acquisition as a hierarchical decision problem. Software acquisition management decision options do not fall entirely in the domain of any single participant community, yet each party is affected by the other's decisions. HHM provides the necessary insight and coordination structure for resolving the competing issues, objectives, and decision opportunities of the several participant communities as they impact the project's cost and schedule.