Most of the solution in SOA, like the cluster of UDDI registries, are based on an hierarchical structures because this is the way humans do in order to deal with complexity, i.e. in order to create comprehensible models.
But as a matter of fact, the reality is not hierarchical at all, this is the reason why information models becomes more and more unmanageable with the increase in complexity. Below a certain degree of complexity, the model can be oversimplified and a hierarchy represent a good approximation, but when complexity increases, it becomes impossible to stick to an hierarchy because reality is not as simple and it's based on different models and topologies, for example Scale Free Networks.
12 September, 2006
07 September, 2006
The risks in understimating MDA
MDA, if applied correctly, promises to change the way we deal with software development:
MDA approach need to be supported by a proper method, process and tool otherwise it'd not be possible to achieve the provisioned advantages, on the contrary the project may collapse at a faster pace then non MDA based projects.
- is it everything going to change?
- Are we really going slim down classical software development methods and processes?
- What shall we expect and tackle in a MDA/MDD based project?
MDA approach need to be supported by a proper method, process and tool otherwise it'd not be possible to achieve the provisioned advantages, on the contrary the project may collapse at a faster pace then non MDA based projects.
Why do we still need username and passwords?
What are passowrds for? I got cookies, PKI, signatures . A password is of the old time, IT need to get rid of it.
02 September, 2006
The impact of UML documentation on software maintenance
There is an interesting article on IEEE transaction on Software engineering volume 32 June 2006 about "The impact of UML documentation on software maintenance".
The conclusions of two experiments are mostly consistent.
No savings in effort are visible.
the conclusion of the article are:
This pare presents the results of two consecutive experiemnts which have taken place in two different locations. The goal was to shed some light on the cost effectiveness of model-driven development with UML. because this is a very large area of ivestigaiton, we focused on whether models help software engineers to make quicker and better changes to existing systems. It is very ocmmon in practice to have software engineers making changes to systems they have not developed and maintenance consumes a large portion of the resources in typical software organisations . This why we thouht that this was an important first question to investigate , though we realize that model-driven development can be useful in many others ways(e.g. code generation). The result of our two expriments are mostly consistent. When considering only the time required to make code changes , using UML documentation does help to save effort overall. On the other hand, when including the time necessary to modify the diagrams, no savings in effort are visible. However, in term of the functional correctness of the changes, both experiments seem to indicate using UML has a significant , positive impact on the most complex tasks.
In my opinion this result reflects two importants points
1) the tools for approaching MDA are not mature , they can improve in usabilty
2) the skills for working with MDA with effectiveness are very high
what we need to lower the cost are probably some tools MDA that simplify the use of some subset of UML, so we can use "normal" people.
what you think?
The conclusions of two experiments are mostly consistent.
No savings in effort are visible.
the conclusion of the article are:
This pare presents the results of two consecutive experiemnts which have taken place in two different locations. The goal was to shed some light on the cost effectiveness of model-driven development with UML. because this is a very large area of ivestigaiton, we focused on whether models help software engineers to make quicker and better changes to existing systems. It is very ocmmon in practice to have software engineers making changes to systems they have not developed and maintenance consumes a large portion of the resources in typical software organisations . This why we thouht that this was an important first question to investigate , though we realize that model-driven development can be useful in many others ways(e.g. code generation). The result of our two expriments are mostly consistent. When considering only the time required to make code changes , using UML documentation does help to save effort overall. On the other hand, when including the time necessary to modify the diagrams, no savings in effort are visible. However, in term of the functional correctness of the changes, both experiments seem to indicate using UML has a significant , positive impact on the most complex tasks.
In my opinion this result reflects two importants points
1) the tools for approaching MDA are not mature , they can improve in usabilty
2) the skills for working with MDA with effectiveness are very high
what we need to lower the cost are probably some tools MDA that simplify the use of some subset of UML, so we can use "normal" people.
what you think?
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