Swapan Bhattacharya

Measuring complexity of component based architecture: a graph based approach

Component based software development (CBSD) is an evolving paradigm where emphasis is laid on reuse of existing components and effective designing of components. As complexity of software systems increases, the challenge of CBSD lies in designing highly cohesive, testable components. Researcher community is striving hard to identify the attributes characterizing component-based development and proposing metrics that may help in controlling the complexity of the component-based systems. This paper proposes a metric-based approach for the determination of complexity along with a set of architectural aspects of componentbased architectures. The Component Architecture Complexity Measurement Metrics (CACMM) has been proposed based on Component Architecture Graph (CAG), a graphical model used for representing UML component diagram. Analysis of the graph is done to measure complexity at different levels -- individual component level, component-to-component level and the complexity for the overall architecture. This metrics may be used by developers to assess the component based architecture and if required re-design to create highly cohesive components with minimal coupling. A case study is presented for deriving the complexity along with the other aspects of the architecture.

Analysis of complexity of requirements: a metrics based approach

In this paper we have developed a metrics based model that will help in quantitatively estimating complexity of requirements for object oriented development methodology. Use Case point is a well-known metrics used for estimation based on use cases. Our model goes a step forward and provides a measurement methodology based on other design models like sequence and class diagrams. This metrics model is based on a formal model using Z notation and implemented using a XML based approach. Measuring complexity of a requirement in terms of design elements will help in validating estimates in the design phase and project management in the long run.

CAG: A Component Architecture Graph

This paper proposes a graph-based approach for the specification of component-based architectures. We have proposed Component Architecture Graph (CAG), a new graphical model for representing UML component diagram. A set of metrics has been defined based on this graph, which will help in measuring several architectural aspects of a system. A case study is presented for presenting the new graphical model and analysis based on the metrics has been discussed.

A mathematical reusability model for quantifying the reduction in development effort

Software Effort and Cost Estimation is a very important activity that includes very uncertain elements. In the context of object-oriented software, traditional methods and metrics were extended to help managing this activity. Use Case Points (UCP) is a very well known metrics used for estimation of object-oriented systems. Use case models are used in Object-Oriented Analysis for capturing and describing the Functional-Requirements of a system. Several methods for estimating software development effort are based on attributes of a use case model. In this paper, we propose a mathematical model based on vectors to measure reusability of software design in terms of reusability of the use cases. Increasing reusability of the use case model would lead to decrease in development effort. Using the vector model, we propose an approach to measure Complexity Reduction Factor (CRF) which measures percentage decrease in effort and hence in cost with increasing reusability. This quantitative analysis of effort reduction with increased reusability would enable us in designing reusable and cost effective software much earlier in software development life cycle, right at the requirement engineering phase. We have used requirements of an Insurance system as a case study to illustrate our approach.

Scenario path identification for distributed systems: A graph based approach

With increased complexity of software systems being developed; analysis of use case scenarios is gaining importance leading to effective test case identification during early part of the life cycle. Existing approaches provide various methods for analysis of UML activity diagrams and scenario path identification based on graph models of activity diagrams. In most cases these methods consider a single activity diagram. However use case scenarios may span multiple activity diagrams, which have become quite common with distributed development of software systems. In this paper we propose Activity Relationship graph model that depicts the interrelationship of activity diagrams modeling a use case. Activity Relationship graph ARG is a hierarchical graph where each node depicts an activity diagram modeled as activity diagram graph (AG). We also define a set of metrics named Use case Scenario Paths (USP) that measures the minimum number of independent paths in ARG. An algorithm is proposed to analyze ARG and derive the number of Use case Scenario Paths. This gives a measure of the number of test paths for a requirement based on analysis models early in the life cycle.

Object relational implementation of Graph based conceptual level Multidimensional Data Model

Data Warehouse (DW) design demands a methodical support for the designer of DW to specify the execution system efficiently from its conceptual level design. This paper proposes a systematic approach of object relational implementation for Graph Object Oriented Multidimensional Data Model (GOOMD model). The approach is governed by some set of conversion rules to specify the GOOMD model construct in SQL 2003 compatible Object Relational Schemas. The concept of GOOMD model also has been implemented in Generic Modeling Environment (GME) and an interpreter has been developed to automate the proposed approach.

Formalization of the design phase of software lifecycle: a grammar based approach

In Object Oriented systems, the design phase can be modeled using the three diagrams: Sequence diagram (which depicts responses of all objects that are involved in a single use case), Class Diagram (which is used to depict the structural aspect of design) and State chart diagram (which is used to depicts the states and state dependent behavior for objects). In this paper, we have proposed a framework for verification of these diagrams, which includes syntactic correctness and inter-diagram consistency. This is done by proposing Context Free Grammar for the three diagrams. The proposed grammar is validated by using Lex and Yacc and parse tree is generated which is an alternate form of the grammar. This framework, being built based on a formal approach, would enable us to automate the process of correctness and consistency verification among the diagrams used in design phase. This would also help us in ensuring requirement traceability on the long run.

Analysis of object-oriented design: A metrics based approach

In this paper, we have proposed a set of metrics to quantitatively estimate the amount of consistency in object-oriented design based on UML use case, activity and class diagrams for a requirement. We have proposed a Design Compliance Metrics II (DCM-II) to quantitatively measure the extent of consistency between use case, activity and class diagrams implementing the use cases for the same requirement. The basis of measuring consistency is the relationship between them based on the common elements. It also helps in measuring progress of a project and thus helps in project management. DCM-II verifies whether the requirements that have been covered in design have been consistently realized in activity and class diagram.

A graph object oriented database model in distributed environment

The graph data model allows us to view a database in a graph G(V,E). For any large semi-structured application under distributed environment, the entire database needs to be fragmented at different sites for better utilization of the existing resource. The graph model also needs the fragmentation in such a way that the fragmented subgraphs can constitute the original graph without any loss. In this paper, the proposed graph data model has been utilized in a distributed environment with suitable examples in the area of a hospital management system.

Two-Stage Gasification of Wood with Preheated Air Supply

This paper presents the results of an experimental study on two-stage gasification of wood with preheated air. Very clean gas having a tar content of about 10 mg/Nm or lower could be obtained from such gasification. For a given primary airflow rate, increase in the secondary airflow rate of the two-stage gasifier resulted in a decrease in tar content and CO2 concentration while the concentration of CO and H2 increased.