Conceptual design of web application families: the BWW approach

1
Conceptual design of web application families
the BWW approach
OOPSLA 20066 th Workshop on Domain-Specific
ModelingOctober 22, 2006Oregon Convention
Center, Portland, Oregon

• Roberto Paiano roberto.paiano_at_unile.it
• Anna Lisa Guido annalisa.guido_at_unile.it
• Andrea Pandurino andrea.pandurino_at_unile.it

2
The scenario

• When the application domain is very large and
  several applications can be obtained from the
  design, it is important to formalize in some way
  the domain knowledge.
• To manage this complexity in the design of
  specific application many methodologies are born
  especially in the design of web application.

• The scenario becomes more and more complex when
  the designer has to model not a specific
  application (that solves a specific problem) but
  a family of applications about a knowledge domain.

3
The overall scenario
4
The conceptual model experience

• Many well-known methodologies exist to model and
  develop the specific application but there isnt
  a standard approach to model the whole domain
  knowledge.

• The main goal is to introduce an experience in
  the conceptual model of a specific domain.
• This experience has been performed into the
  industrial research project called Genesis-D
  (Global Environmental Network System of
  Information for Sustainable Development)
  sponsored by Edinform SpA.

5
The environment domain

• It is a very complex application domain
• Great number of stakeholders
• The necessity to acquire and to organize the
  knowledge from different sources
• Coherent data exchange between the different
  stakeholders
• Different objects are used with the same semantic
  in different contexts

6
The two approach

• In detail, we evaluate the objectiveness and
  usefulness (in order to design and to develop a
  web information system) two different approaches
• The use of classic techniques within software
  engineering. Due to the domain dimension and
  complexity, it is too hard to use a
  fully-compliant UML approach, thus, the UML-like
  approach adopts the main concepts of Object
  Oriented customized for the specific purpose.
• The use of the formal ontology. This approach
  uses the classification of the concepts proposed
  by BWW in order to represent the domain concepts
  and their relationships with a well-known
  semantics.

7
The UML-like approach

• At the conceptual modeling abstraction level it
  seems unsuitable to use a fully-compliant Object
  Oriented approach.
• According to the abstraction level and to the
  necessity to manage all the information in a few
  diagram (in order to not have a fragmented
  design), in the conceptual model we use only the
  class diagram.

8
The UML-like approach

• In the UML-like approach the modeling process is
  made up through several iterations each
  iteration has the goal to refine the analysis and
  therefore to describe the application domain in a
  more and more precise way.
• Because of the conceptual modeling abstraction
  level, it is not possible to use object for
  which it is necessary to identify the state and
  behavior of entire domain reality.

In the diagram, we use the Entity that may
contain some attributes.
9
The UML-like approach steps
Step Description Example
1. Analysis of entities Provide a description of the information entities and the relationships among them Alteration biological variety, climatic change, consumption of soils, soil degradation, pollution, wastes radiation, noise, FIA class (Fact of Environmental Interest) For FIA class all the parameters are grouped in the IIP class (Indicator, Index, Parameter)
2. Analysis of entities attributes Entities are refined (through the definition of the attributes, of their type and of the methods) For Features Name, period of life, Category, status
10
The UML-like approach example
In the UML-like approach the designer describes
the phenomena creating the FIA class (Fact of
Environmental Interest) and all the parameters
are grouped in the IIP class (Indicator, Index,
Parameter) strictly related to the Metrics class.
Using an analogous procedure, other abstract
classes are identified Objects, Subjects and
Structures (OSS) to which each FIA makes
reference.

• FIA, IIP and Metrics are Abstract Classes.

The class OSS contains the Subjects (physical or
juridical person that can be interested or
involved in facts and environmental phenomena),
the Objects (any object or territorial structure
inside which the characteristic processes of the
human social lifetime are based and are
developed) and the Structures.
11
The use of BWW concepts

• The BWW concepts classification are adapted to
  our needs
• Adding the relationship of a thing with itself
• Adding property in order to characterize the
  events.
• In detail, using the OWL
• first we defined the meta-model of BWW concepts
• then using the meta-model, the environment domain
  model (target of our research work) is modeled.

12
The BWW approach steps
Step Description Example
1. Analysis of things Highlight domain thinks Water Basin, Water Body, Public Corporation
2. Analysis of classes Highlight domain classes The properties shared between Water Basin and Water Body define a class (Hydrographic object)
3. Mutual property Select mutual property of each class For Public Corporation Regulation, dimension, category,..
4. Intrinsic property Select intrinsic property of each thinks and classes For Public Competence Name, function,..
13
The BWW approach steps
Step Description Example
5. Characterization of property each mutual / intrinsic property is tied up to both human and natural laws. This characterization of the properties introduced by BWW, has led us to reflect them in the environmental domain. The territorial competences of the Public Corporation are, for instance, defined by decrees. The decrees result, therefore, in a characterization of the Intrinsic Property territorial competences and, particularly they are Human Law this means that territorial competencies are constraints by the Human Law decree. BWW attributes allow us to take into consideration the correct semantic of a concept (decree).
14
The BWW approach steps
Step Description Example
6. Events Define what it happens the events are in partnership with a thing or class and, when they occur, change a well defined property of the Thing or of the class to which they are associated. An OSS creates a FIA that, in turn, is created when the variation of an indicator produces an alarm. The alarm is an events. Using the BWW approach the FIA has been modeled as an history of the value of indicators thus, the concept of FIA has the correct semantics.
7. System Select different part of the same Conceptual model BWW defines the systems as the joining of things intending that the things belonging to the system influence the properties of each other
15
Comparison between the two approaches

• BWW approach advantages
• Objective the concepts classification helps to
  represent the application domain without focus on
  a particular point of view.
• the domain model is directly expressed using well
  defined and categorized domain concept through
  real world concept such as thing, classes, law
  and so on where the domain concept is easy to
  map.
• It supports directly Events and the concept of
  input and output in relationship with the concept
  of thing is coupled with, generate output and so
  on (intrinsic in BWW) give the right semantics.
• It is easy to realize and easy to use for those
  who will deal with the following phases of
  analysis and implementation.
• It is technology independent.

16
Comparison between the two approaches

• The UML-like approach allows to describe a domain
  using an incremental method.
• Advantages
• the designer improves the analysis step by step
• the output can be directly used through the UML
  standard notation to create the final product
• Disadvantages
• the output is an Object Oriented model that
  implements the typical constructs of this
  paradigm.
• the process is strongly dependent on the
  experience of the designer who must analyze the
  application domain and must be skilled at OO
  modeling

17
Comparison between the two approaches

• The main UML-like disadvantage is that the
  semantic is flattened and the concept of entity
  is used also to model very different concepts
• For instance, in the UML-like modeling, the FIA
  and the indicator are both modeled as entity but
  the FIA is a set of values (not previously
  defined) that the indicator can assume at the
  time a FIA is registered when some value of an
  indicator changes.

18
Conclusions

• The case study presented in this research work is
  very complex, so we think that the considerations
  made for this case study are also valid for other
  case studies.
• To check the BWW domain model, we also studied
  the WA used by the Authority of basin of PO river
  that is perfectly represented into the conceptual
  model designed.

19
Conclusions

• The BWW approach allows the provision of the
  right semantics and therefore it expresses all
  the domain details directly using the domain
  concepts. The model is objective thanks to the
  classification of the concepts provided by BWW
  and it is not tied to a specific implementation
  technology.
• The UML-like approach appears particularly
  effective because, being a lot closer to an
  implementation technology, allows us to directly
  reach the realization of a family of applications
  in a particular application domain.
• The objectivity and the simplicity of the BWW
  approach encourages the use of this approach for
  the conceptual modeling of application domains of
  great dimensions.

20
Future trend

• In order to keep under control the typical
  aspects of web applications and therefore to
  manage the user experience, we are designing two
  web application starting from the conceptual
  model of the environment domain.
• Our efforts are focused on the definition of
  guidelines to obtain an IDM (Interactive Dialog
  Model) design starting from the domain modeling.
• As future work we plain to design and implement
  an editor in order to help the designer to apply
  the guidelines that we are defining.