Sunday, 29 July 2012

Overview of the system and Functional requirements


 Overview of the system:
Now a day the usage of credit cards has dramatically increased. As credit card becomes the most popular mode of payment for both online as well as regular purchase, cases of fraud associated with it are also rising. In this paper, we model the sequence of operations in credit card transaction processing using a Hidden Markov Model (HMM) and show how it can be used for the detection of frauds. An HMM is initially trained with the normal behavior of a cardholder. If an incoming credit card transaction is not accepted by the trained HMM with sufficiently high probability, it is considered to be fraudulent. At the same time, we try to ensure that genuine transactions are not rejected. We present detailed experimental results to show the effectiveness of our approach and compare it with other techniques available in the literature
Areas of Selections:
Front End: Visual Studio 2005(VB.NET 2.0)
Back End: MS SQL SERVER 2005.

Functional requirements:
                The functional requirement describes the interaction between the system and its environment independent of its implementation. The environment includes the user and any other external system with which the system interacts.
2.3.1 Actors:
Actors are external entities that interact with the system. Actors typically include a user role or another system. They have unique names and descriptions.
      Server
      Client

2.3.2 Use cases:
      Use case used during requirements elicitation and analysis to represent the functionality of the system. Use case describes a function provided by the system that yields a visible result for an actor.
        The identification of actors and Usecase results in the definition of the boundary of the system that is, differentiating the tasks accomplished by the system and the tasks accomplished by its environment. The actors are outside the boundary of the system, where as the Usecase are inside the boundary of the system.
Use cases describe the behavior of the system as seen from the actor’s point of view. It describes the function provided by the system as a set of events that yield a visible result for the actors.
Actors initiate the use cases for accessing system’s functionality. When actors and use cases exchange information, they are said to Communicate. To describe a use case we use a template composed of six fields:

Use Case Name:                   The name of the use case
Participating Actors:    The actors participating in the particular use case
Entry Condition:                   Condition for initiating the use case.
Flow of events:                      Sequence of steps describing the functioning of use case.
Exit Condition:     Condition for terminating the use case.
Quality Requirements: Requirements that do not belong to the use case but Constraint the functionality of the system
Use case diagrams include four types of relations. They are as follows:
      Communication Relationships
      Inclusion Relationships
      Extension Relationships
      Inheritance Relationships

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