Journal of Software Engineering and Applications, 2011, 1, 18-22
doi:10.4236/jsea.2011.41003 Published Online January 2011 (http://www.scirp.org/journal/jsea)
Incorporating AOSD to Enhance Model Driven
Architecture
Yashwant Singh1, Manu Sood2, Tarun Gupta1, Atish Thakur1
1Department of Computer Science Engineering and Information Technology, Jaypee University of Information Technology, Wak-
naghat, India; 2Department of Computer Science, Himachal Pradesh University, Shimla, India
Received December 14th, 2010; revised December 21st, 2010; accepted January 12th, 2011.
ABSTRACT
Various software development approaches in the present scenario are best suited for a specific application. The soft-
ware development strategies include both merits and demerits when talked in terms of generalization. The Model Dri-
ven Architecture (MDA) describes software development based on models on various levels of abstraction. The model
driven software development process consists of sequence of model transformations between various models. This pa-
per presents incorporation of the merits of Aspect Oriented Software Development (AOSD) like modularization, reusa-
bility and reduced complexity into Model Driven Architecture (MDA) software development strategy. The proposed
Model Driven Software Development approach which combines the merits of MDA and AOSD meets the ever changing
and challenging demand of the enterprise software development.
Keywords: Model Driven Architecture, Aspect Oriented Software Development, Computational Indepe nde nt Mod el,
Platform Independent Model, Platform Specific Model
1. Introduction
Various day-to-day advancements are made in the field
of Software development approaches. It results in erup-
tion of various software development approaches to spe-
cific enterprise systems. The use of new technologies and
modern trends are not being considered sufficiently due
to the software development paradigm shift. One such
solution of the problem could be a regular study program
review and integration of new modules into the current
software development processes.
The challenges faced by enterprise software develop-
ment are the effective design of software system to sup-
port ever-changing business capabilities in a timely ma-
nner and bridging the vision of an application to its rea-
lization. One such so lution to the problem is provided by
Model Driven Architecture approach of software devel-
opment under Model Driven Software Development
(MDSD).
MDA approach of software development under MDSD
helps producing three models [1]: 1) Computation Inde-
pendent Model (CIM), which specifies the models for
domain and requirements of the system, 2) Platform In-
dependent Model (PIM), which specifies the models for
abstract concepts of the system and excludes platform
specific details and 3) Platform Specific Model (PSM),
which specifies and models how the functionality in a
PIM is brought to reality on a specific computing plat-
form, with high abstraction.
MDA also supports the transformations [2] from CIM
to PIM and from PIM to PSM. Transformatio n of PIM to
PSM includes specifying the rules to transform a PIM
into [3]. 1) An application layer model to be implemented
using object oriented languages, 2) A database layer mo-
del to be implemented using RDBMS, and 3) An interac-
tion between application layer and database layer is also
implemented by object oriented languages like JAVA; all
as a part of PSM.
This paper is an attempt to incorporate the merits of
(AOSD) [4] into Model Driven Architecture approach of
software development. The Aspect-Oriented Software
Development decomposes a software system into mod-
ules in such a way that modules responsible for a com-
mon concern are tightly coupled and modules responsible
for different concerns are loosely coupled. Aspect-Ori-
ented Software Development is a post object-oriented te-
chnology that helps achieve better separation of concern
by providing mechanisms to localize concerns like secu-
rity, synchronization, and logging in software develop-
ment process. Fur thermore new MDA models CIM, PIM

Incorporating AOSD to Enhance Model Driven Architecture 19
and PSM with added advantages of Aspect Oriented
Software development has been proposed.
The remainder of this paper is organized as follows:
Section 2 gives the illustration of Model Driven Archi-
tecture with its various models. Section 3 presents Aspect
Oriented Software Development (AOSD) and its impor-
tance in development of enterprise system. The proposed
MDA approach of software development with added ad-
vantages of AOSD illustrated in Section 4. The compar-
ison between traditional and proposed model has been
shown in Section 5 and Section 6 presents conclusion.
2. Motivation the Model Driven
Architecture
MDA is a flagship initiative of the Object Management
Group (OMG) [2,5] presenting a new vision on how en-
terprise systems should be developed and managed.
Launched in 2001, MDA is now making a great impact
in the areas related to the enterprise software develop-
ment. It is an approach that addresses the increasing
complexity in enterprise-system design by combining
various technologies for an effective software develop-
ment. The MDA approach is a model-centric paradigm
which automates the generation of system implementa-
tion artifacts from the model directly [6]. The approach
works on the following layers of model:
 Comput at ion Independent Model (CIM)
 Platform Independent Model (PIM)
 Platform Specific Model (PSM)
The Figure 1 shows the various models, transformations
and mappings of MDA.
2.1. Computation Independent Model
A CIM is also often referred to as a business or domain
model. It describes the actual requirement of the system
and hides all technology specific details related to speci-
fication. It presents a system independent specification
by abstracting the technology specifications and provides
a bridge between the domain experts and information
CIM
Transformation
PIM
Transformation
PSM
MDA
Figure 1. Model Driven Architecture.
technologists which are responsible for the development
process. The OMG MDA guide refers to the Computa-
tional Independen t Model as the highest level of abstrac-
tion. In terms of the MDA [7] refers CIM as real world
model.
2.2. Platform Independent Model
The PIM does not include any platform specific details; it
obtains the domain’s key features. The main objective of
the PIM is to create the precise concept of the system
using the vocabulary of the domain as far as possible. A
software developer can represent this concept through
models in different modeling languages. PIM demands a
general representation to capture the semantics of many
different domains, which should also be precise enough
to support transformation into target cod e [8].
A PIM exhibits a sufficient degree of independence so
as to enable its mapping to one or more platforms [9].
This is commonly achieved by defining a set of services
in a way that abstracts out technical details. Other models
then specify a realization of these services in a platform
specific manner.
2.3. Platform Specific Model
A PSM combines the specifications in the PIM with the
details required to stipulate how a system uses a particu-
lar type of platform. If the PSM does not include all of
the details necessary to produce an implementation of
that platform it is considered abstract which means that it
relies on other explicit or implicit models which do con-
tain the necessary details. The key features of PSM are as
follows [8,10]:
 Specifies how the functionality in a PIM is brought
to reality on a specific computing platform.
 Derived from the PIM by adding some plat
form-specific details to the standard components.
 Multiple PSMs can be associated with a single PIM.
 Designed to specify the target platform system.
3. Aspect Oriented Software Development
The Software development of complex software applica-
tions is a challenging task. Computer hardware and soft-
ware have evolved together over the years. In the early
days, due to hardware limitations, the problems solved by
computers were simple, easier and also the software ap-
plications written to solve them were not complex. Mod-
ern software development or software engineering is more
than just coding; it is an iterative process made up of sev-
eral stages with methodologies to guide each stage and
also have tools to support each and every methodology [4].
Aspect-oriented technology is not different from oth-
ers it just followed the aspect oriented languages and
extended the idea to the entire software development

Incorporating AOSD to Enhance Model Driven Architecture 20
Figure 2. Proposed Architecture (Combining AOSD principles with MDA).
process and forming the field of Aspect-Oriented Soft-
ware Development (AOSD) [6]. It provides unique and
advanced program structuring and modularization tech-
niques.
The implementation of software applications using
AOSD techniques provides a better software implemen-
tation structure which has an impact on many important
software qualities such as improved interoperability, po r-
tability, longevity, enhanced reusability and reduced com-
plexity. It is desirable to decompose a system into differ-
rent modules in such a way that modules responsible for
a common concern are strongly coupled and modules re-
sponsible for different concerns are weakly coupled.
AOSD helps to achieve better Separation of Concerns
(SOC) by providing methods to localize cross-cutting
con-cerns like security, synchronization, and logging in
software artifacts throughout the software development
process. Using AOSD the different concerns in real ap-
plications are modularized, developed separately and then
woven together to create software applications.
4. Proposed Approach
The architecture illustrated in Figure 2 include the in-
corporation of Aspect-Oriented Software Development
(AOSD)[4] concepts in the Model Driven Architecture
approach of software development [2,11]. The proposed
architecture makes it more suited to the challenging and
changing demands of the present enterprise software de-
velopment. Analysis and implementation of both func-
tional and non-functional requirement plays equally im-
portant role in the development process. The highly
reusable MDA is clubbed with the separation of concerns
(non-functional requirement) and analyzing them sepa-
rately with the core requirement. AOSD helps meet the
challenges of MDA such as comprehensive modeling
standards and mapping technologies with its modulariza-
tion and weaving concepts. The Architecture uses the
base as the MDA with its three broad layers and com-
bines the modularization, concern separation concepts of
AOSD. The new three layers of the modified MDA are:
 Modified CIM
 Modified PIM
 Modified PSM
4.1. Modified CIM
The Computational Independent Model Layer is divided
into different module layers by combining aspect orien-
ted programming concepts as depicted in Figure 3 and
different module layers are as follows:
4.1.1. Module L aye r
It includes the identification of various modules present
in the enterprise software system. The application that
needs to be designed is broken into sub-systems or mod-
ules so as to reduce the complexity of the system and
model each sub-system uniquely. The breaking up of the
main application into sub-systems facilitates the efficient
design and analysis of each part.
4.1.2. Identifying Core Functionality and Concerns
The module layer is further divided into Core Functio-
nality Layer (CF) and Concerns.
 Core Functionality (CF): Each module is analyzed
for the core functionality and a CF is prepared.
 Concerns: The concern layer consists of the com-
mon non-functional requirement in the modules.
The functional and non-functional requirements are
separated so that they can be modeled more specifically.
The output of these 2 layers is passed to the next MDA
layer, i.e., Platform Independent Model (PIM).

Incorporating AOSD to Enhance Model Driven Architecture 21
Figure 3. Modified CIM LAYER
Figure 4. Modified PIM.
4.2. Modified PIM
This model include the specifications of how the things
need to be done, hiding the details about the technology
that will be employed to implement, the modified PIM as
in Figure 4 contains the separate specification details
related to Core Functionality (CF) and the Con cerns. The
PIM is divided into Platform Independent Functional
Module (PIFM) and The Platform Independent Concern
Module (PICM).
4.2.1. PIFM
The Platform Independent Functional Module (PIFM)
includes the implementation details of the core functio-
nalities of the specific modules that are modeled in the
Computational Independent Model. It helps to develop
an outline that is technology independent and thus pro-
vide a high degree of reusability.
4.2.2. PIC M
The Platform Independent Concern Module (PICM) in-
cludes the details of how the different concerns would be
implemented. As the concerns are needed with various
modules so the technology independent code provides
great level of reusab ility.
4.3. Modified PSM
The PSM Layer is broken into two layers namely core
functionality and concern layer and weaving layer as
shown in Figure 5:
4.3.1. Implementing Core Functionali ty and Co nc ern s
The Layer provides the technology specific implementa-
tion of the core functionality and the different concerns
identified.
 PSFM: Platform Specific Functional Module (PSFM)
provides the implementation of core functionality of
the modules which is technology specific or platform
dependent. The PIFM provided by the PIM layer is
implemented usi ng the desired t echnology .
 PSCM: Platform Specific Concern Module (PSCM)
provides the implementation of various concerns of
the system by a technology specific code. It imple-
ments the PICM provided by the PIM layer for each
concern.
4.3.2. Wea ving Layer
The last layer includes the merging of core co ncerns with
the different concerns needed by the particular module. It
contains the set of rules that defines the integration of
functional and non-functional requirements of the system
providing a one complete system ready to be deployed.
In this layer different modules are woven together to
create a software application of enterprise systems.
5. Traditional Model vs. Proposed Model
The comparison to the traditional model with the pro-
Figure 5. Modified PSM.

Incorporating AOSD to Enhance Model Driven Architecture 22
posed can be viewed as follows:
5.1. Traditional & Modified CIM
The Traditional CIM provid es a system independent spe-
cification by abstracting the technology specification.
The specifications are monitored as a combined view of
functional and non-functional requirement with no spe-
cific module discrimination.
The proposed CIM first identifies the major sub mod-
ules of the system so that they can be analyzed and de-
signed more specifically and individually. After the mo-
dule separation the functional and non-functional re-
quirements are separated and modeled. The separation
benefits the issue of reusability and ease of modeling.
The consideration of core-functionality and concerns
separately is the main implementatio n focus of the AOSD
model, which is incorporated in the MDA approach.
5.2. Traditional & Modified PIM
The traditional PIM provide the platform independent
details with presenting domain’s key feature. The mod-
ified PIM does no t include any sign ificant tran sformation
except the modeling of core functionality (PIFM) and
concerns (PICM) separately without specifying the plat-
form specific details. The separated modeling benefits in
considering g the design of non-functional requirements
as well as functional requirement with more concerned
focus that leads to efficient design of the system and in-
creases reusability in the model.
5.3. Traditional & Modified PSM
Traditional PSM include the transformation of PIM to
PSM including the platform and technology specific de-
tails. The proposed PSM include the transformation as
same with the traditional but require two transformations
i.e., from PIFM to PSFM and PICM to PSCM.
The weaving model presented as an advantage over
the traditional model as the layer specifies the rules to
group the core functionality with the concerns. The grou-
ping process is dynamic which increases the flexibility
and scalability of the module.
6. Conclusions
Enterprise Information System is the main artifact of the
enterprise information construction. The study of how to
improve the quality, longevity, cost of production and
success rate of enterprise Information System is absolu-
tely necessary and significant. The MDA software deve-
lopment approach in the recent years has been able to
improve all these above listed factors by separating the
concern through ab straction s at var iou s levels. This p aper
has shown that the notion of various highly reusable
models in MDA by combining the merits such as better
separation of concerns, modularization and weaving con-
cepts of Aspect-Oriented Software development (AOSD).
Modified MDA has been proposed which is best suited to
the ever changing demand of the enterprise system de-
velopment. The architecture helps in modeling each and
every requirement of the system efficiently.
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