CushionTheBlow (구 BluemoonSoft)

In n-tier architecture an application server is a server that hosts an API to expose Business Logic and Business Processes for use by other applications [1]. The term can refer to:

1. The Services that are made available by the server
2. The Computer Hardware on which the Services are deployed
3. The Software framework used to host the Services such as JBoss application server or Oracle Application Server

Reference:
http://en.wikipedia.org/wiki/Application_server

AndroMDA (pronounced "Andromeda") is an extensible generator framework that adheres to the Model Driven Architecture (MDA) paradigm. Models from UML tools will be transformed into deployable components for your favorite platform (J2EE, Spring, .NET). Unlike other MDA toolkits, AndroMDA comes with a host of ready-made cartridges that target today's development toolkits like Axis, jBPM, Struts, JSF, Spring and Hibernate. AndroMDA also contains a toolkit for building your own cartridges or customize existing ones - the meta cartridge. Using it, you can build a custom code generator using your favorite UML tool.

Reference:
http://galaxy.andromda.org/index.php?option=com_content&task=blogcategory&id=0&Itemid=42

Model-driven architecture (MDA) is a software design approach for the development of software systems. It provides a set of guidelines for the structuring of specifications, which are expressed as models. Model-driven architecture is a kind of domain engineering, and supports model-driven engineering of software systems. It was launched by the Object Management Group (OMG) in 2001.

Overview
The Model-Driven Architecture approach defines system functionality using a platform-independent model (PIM) using an appropriate domain-specific language.

Then, given a platform definition model (PDM) corresponding to CORBA, .NET, the Web, etc., the PIM is translated to one or more platform-specific models (PSMs) that computers can run.

The PSM may use different Domain Specific Languages, or a General Purpose Language like Java, C#, PHP, Python, etc. Automated tools generally perform this translation.

The OMG organization provides rough specifications rather than implementations, often as answers to Requests for Proposals (RFPs). Implementations come from private companies or open source groups.

MDA principles can also apply to other areas such as business process modeling where the PIM is translated to either automated or manual processes.

Reference:
http://en.wikipedia.org/wiki/Model-driven_architecture