Constructive Cost Model


(COCOMO) A method for evaluating the cost of a software package proposed by Dr Barry Boehm. There are a number of different types:

The Basic COCOMO Model estimates the effort required to develop software in three modes of development (Organic Mode, Semidetached Mode, or Embedded Mode) using only DSIs as an input. The Basic model is good for quick, early, and rough order of magnitude estimates.

The Intermediate COCOMO Model an extension of the Basic COCOMO model. The Intermediate model uses an Effort Adjustment Factor (EAF) and slightly different coefficients for the effort equation than the Basic model. It produces better results than the Basic model because the user supplies settings for cost drivers that determine the effort and duration of the software projects. The Intermediate model also allows the system to be divided and estimated in components. DSI values and cost drivers can be chosen for individual components instead of for the system as a whole.

The Detailed COCOMO Model differs from the Intermediate COCOMO model in that it uses effort multipliers for each phase of the project. These phase dependent effort multipliers yield better estimates because the cost driver ratings may be different during each phase. The detailed model also provides a three-level product hierarchy and has some other capabilities such as a procedure for adjusting the phase distribution of the development schedule.

["Software Engineering Economics", B. Boehm, Prentice-Hall, 1981].

Last updated: 1996-05-29

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constructed typeConstructive Cost Modelconstructive proof

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constructive proof


A proof that something exists that provides an example or a method for actually constructing it.

For example, for any pair of finite real numbers n < 0 and p > 0, there exists a real number 0 < k < 1 such that

	f(k) = (1-k)*n + k*p = 0.

A constructive proof would proceed by rearranging the above to derive an equation for k:

	k = 1/(1-n/p)

From this and the constraints on n and p, we can show that 0 < k < 1.

A few mathematicians actually reject *all* non-constructive arguments as invalid; this means, for instance, that the law of the excluded middle (either P or not-P must hold, whatever P is) has to go; this makes proof by contradiction invalid. See intuitionistic logic.

Constructive proofs are popular in theoretical computer science, both because computer scientists are less given to abstraction than mathematicians and because intuitionistic logic turns out to be an appropriate theoretical treatment of the foundations of computer science.

Last updated: 2014-08-24

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Constructive Cost Modelconstructive proofconstructive solid geometry

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constructive solid geometry


(CSG) A method for describing the geometry of complex scenes by applying set operations to primitive objects.

See also CSG-tree.

[What operations? What objects?]

Last updated: 1998-06-09

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constructive proofconstructive solid geometryconstructorConsul

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