On the representation of intangible objects such as software in a measurement context
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On the Representation of Intangible Objects such as Software in a Measurement Context. Miguel Lopez Valérie Paulus Grégory Seront Simon Alexandre. Questions. Are software so intangible that measurement of such abstract beings is impossible? Is the nature of software so impalpable?

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On the Representation of Intangible Objects such as Software in a Measurement Context

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On the representation of intangible objects such as software in a measurement context

On the Representation of Intangible Objects such as Software in a Measurement Context

Miguel Lopez

Valérie Paulus

Grégory Seront

Simon Alexandre


Questions

Questions

  • Are software so intangible that measurement of such abstract beings is impossible?

  • Is the nature of software so impalpable?

  • How can we formulate the software representation problem in order to allow measurement?


More questions

More Questions

  • Is it relevant to measure software representations in order to make decisions concerning this software?

  • Are the representations of software relevant and suitable for measurement?


Software models

Software Models

  • To measure, we need a representation of the software because of its intangible nature.

  • The representation of a software is called a model.


Different software models

Different Software Models

  • In the literature, a lot of languages for representing software can be found.

    • UML

    • Graphs

    • Source Code

    • ….


Software meta model

Software Meta-Model

  • The concepts and their relations used for building a model are explained in a meta-model.

  • So, meta-models exist for UML, graphs, and so on.


Software meta model problem

Software Meta-Model Problem

  • How can we select a relevant and suitable meta-model in measurement context?

  • Is that always necessary to use meta-models in order to measure a software?

    • For an external measure, do we have to work with meta-models?


Meta model for measurement

Meta-model for Measurement

  • Measure Definition:

    • Mapping between an empirical set onto a mathematical set.

    • A mapping between an empirical set of objects A and a mathematical set of objects B.

Set B

Set A


Set a problem

Set A Problem

  • Set A is a set of empirical objects.

    • By definition, tangible objects.

  • Are software tangible objects?

    • Is all the software intangible?

    • Or, just some parts, some attributes?

  • Some software attributes are intangible.

    • Coupling, cohesion, complexity,efficiency,…


Set a problem1

Set A Problem

  • So, to perceive those attributes, they need representation or model.

  • Set A is replaced by a set A’ which contains representations of objects of set A.

  • The transformation A -> A’ transforms intangible objects into tangible objects.


Set a problem2

Set A Problem

  • Does the transformation A -> A’ keeps the structure of Set A?

  • When measuring an element of A’, are we measuring the corresponding element of A?

Set B

Set A’

Set A


Build set a

Build Set A’

  • To build the set of representations or models, we need to define the elements used for modeling.

  • These elements are formalized in a meta-model.


Meta model

Meta-Model

  • So, the meta-model must be relevant and suitable in regard with:

    • Measurement Goal

    • Entity: products, projects, process

    • Attribute: properties of the entity: efficiency, coupling,…


Measurement method

Measurement Method

  • A measurement method must at least define:

    • Its goal

    • The considered entity

    • The attribute to be measured

  • In regard with these three elements, a suitable and relevant meta-model must be built or selected.


Entity meta model

Entity & Meta-model

  • In this presentation, only the entity software product is considered.

  • The meta-modelisation aims at modeling the entity.

  • Several types of software product entities exist:

    • Requirements Document

    • Design Document

    • Source Code

    • Executable


Entity meta model1

Entity & Meta-model

  • The meta-model depends on the type of entity.

  • For example:

    • Design Document:

      • Meta-model of UML: class, relations,…

      • Meta-model of graphs: nodes, edges,…


Entity meta model attribute

Entity, Meta-model, & Attribute

  • But, the meta-model also depends on the type of attribute.

  • In regard with the attribute, some meta-models are more relevant and suitable than others.


Entity meta model attribute1

Entity, Meta-model, & Attribute

  • For example, measuring the functional size of a software product with Cosmic-FFP:

    • Entity: Requirements Document

    • Attribute: Functional size


Entity meta model attribute2

Entity, Meta-model, & Attribute

  • Meta-Model: Cosmic-FFP


How to verify the meta model

How to verify the meta-model?

  • Two methods:

    • Expert-based: the relevance and the suitability of the meta-model is evaluated by a set of experts.

    • Empirical: the relevance and the suitability is of the meta-model is evaluated within a set of entities coming real projects.


How to verify the meta model1

How to verify the meta-model?

  • Problems with these two methods:

    • Expert-based:

      • Reliability of the experts judgment.

      • Representativity of the experts sample.

    • Empirical:

      • What does mean suitable and relevant in operational terms?

      • How can we make representative samples?


Advantages to explicit the meta model

Advantages to explicit the meta-model

  • An explicit meta-model allows to better understand the entity and the attribute to be measured.

    • To meta-model an entity like design, source code in terms of a given attribute (coupling,…), it is important to understand and clearly define these terms.


Advantages to explicit the meta model1

Advantages to explicit the meta-model

  • An explicit meta-model allows to identify early in the measurement method, the limits of measurement:

    • Cosmic-FFP meta-model does not take into account the complexity of the data movement.

    • So, the software with complex algorithms are not sized by COSMIC-FFP


Meta model for all types of measurement

Meta-model for all types of measurement

  • Meta-model in external measures are often implicit.

  • It is not necessary to explicit the meta-model of the entity for external measures.

  • Response time: which is the meta-model of the entity?


Conclusion

Conclusion

  • Does the entity meta-model a critical activity in software measurement?

  • Must this activity be explored in details?


Questions1

Questions

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