Quantification Of Functional Requirements In Software System Engineering Using Lpp

Quantification Of Functional Requirements In Software System Engineering Using Lpp

QUANTIFICATION OF FUNCTIONAL REQUIREMENTS IN SOFTWARE SYSTEM ENGINEERING USING LPP

M.Karthika, X.Joshphin Jasaline Anitha

Dr.K.Alagarsamy

Assistant Professor ,MCA DepartmentNMSS Vellaichamy Nadar College Nagamalai,Madurai, Tami Nadu, India

Assistant Professor ,MCA DepartmentNMSS Vellaichamy Nadar College, Nagamalai,Madurai, Tami Nadu, India Associate professor,Computer CentreMadurai Kamaraj University, Nagamalai,Madurai, Tami Nadu, India

ABSTRACT

Software systems developed now-a- days are by and large more complicated than the existing software. There are certain foundational activities for a system development like the objective of the system, operational requirements, role of hardware and software, the people working in it, database used and the procedures. On understanding the foundational activities based on the System Engineering principle to transform an operational need into more descriptive and will lead to build a right and good product with customer satisfaction. The operational requirements of software system engineering have been classified already .In this paper, the functional requirements classified is common for all the software system developed. Also, it brought out the important role of functional requirements which can effectively be uses to elicit information from the customers more precisely and accurately through LPP approach. The LPP assigns, identifies, classifies and optimize the functional requirements which will provide an insight into the system architecture, also helps to communicate the operational and behavioral characteristics of the new system.

Keywords

System Engineering, Software System Engineering, Functional requirements, product, Evaluation criteria,LPP

1. As large systems functions and solutions are dependent on software, System Engineering approach to the development of software will help to avoid the problems associated with the software crisis. These crisis are mainly on the project schedule, cost of estimation, customer satisfaction. A Software product developed may face challenging facts, risks, and issues in managerial aspects such as logistics, lack of co- ordination between the teams developing the product as well as the work process. The need to identify and manipulate the properties of a software system leads to the use of software system engineering. [1]

   A system is a group of co-related objects that allows a common goal to be accomplished. In computer systems, these elements include hardware, software, people, facilities, and processes.

   System engineering is the practical application of scientific, engineering, and management skills necessary to transform an operational need into a description of a system configuration

   that best satisfies that need. It is a generic problem-solving process that applies to the overall technical management of a system development project. This process provides the mechanism for identifying and evolving a systems product and process definitions. System engineering involves five functions: Problem definition, Solution analysis, Process planning, Process control and Product evaluation [7].

   System engineering provides the baseline for all project development, as well as a mechanism for defining the solution space. The solution space describes the product at the highest level before the system requirements are partitioned into the hardware and software subsystems.

   The developed software has become very larger and more complex than the existing software. The complexity has been increased in variety of phases in the software development life cycle. The understanding of the problem must enforce the below mentioned in system engineering [8].

   Requirement analysis Design Implementation

   Verification & Validation Testing

   System Engineering focuses on variety of elements, analyzing, designing and organizing those elements into a system that can become a product, a service or a technology for the transformations or control. Software system engineering manages the technical function of the system products, which produces set of documents. This is a technical process which converts the analytical process into an operational process such as [2],

   Define the problem

   Identify feasible alternatives Select the evaluation criteria Applying modeling techniques Generate input data Manipulate the model

   This paper categorizes and concentrates only on the functional requirements in the software requirement stage in accordance with the principles of system engineering and its tools.

2. The application of system engineering principle to the development of a computer software system prepares activities, tasks and various set of procedures that is called as software system engineering (SwSE).This SwSE can be specifically applied in the development of large complex

   software systems that provides a powerful tool for process and product management. The software system is larger and has high complexity in using it. This will attribute towards the growth in hardware performance as well as the software performance by having reduced software system size which makes the software more complex. The goal of SwSE is to reduce the complexity through several stages of verification and validation.

   Software System Engineering

   Requirement Analysis

   Design

   Planning

   Managing Verification, Validation, Testing

   Fig .1. Phases in Software System engineering

   Software system Engineering manages the technical function of the system products which produces the documents for reference. Evaluation criteria, a series of steps or an iterative process using genetic algorithms can give this documentation reference.

   To achieve a successful process, planning is necessary. Planning tells us the goals in a project the objectives, strategies, polices, plans, and procedure. It tells us in advance what, how, when and who will do the process. To plan a software engineering project we need SWSE management activities that lead in selecting a course of action from alternative possibilities and defining a program for completing those actions.

   The collection of management activities that used to ensure that the project goes according to the plan is known as process control. The performance and results against plans, notes deviations measured using process control. It takes corrective actions to ensure conformance between plans and actual results. Process control gives us a feedback to the system for how well the project is going. In system, engineering V&V is a continuous process of-monitoring system engineering, SwSE, software engineering, and project management

   activities to determine that they are following the technical and managerial plans, specifications, standards, and procedures. V&V. evaluate the interim and final product of software engineering.

   The user satisfaction must meet out through the system engineers. The success of software development process and the system life cycles undergoes much revaluation process to redefine the functional requirements.

   1. The first step in any software development activity is to determine and document the system-level requirements in either a system requirements specification (SRS) or a software requirements specification or both. Software requirements include capabilities that a user needs to solve a problem or achieve an objective as well as capabilities that a system or component needs to satisfy a contract, standard, or other formally imposeddocument. Software requirements analysis begins after system engineering has defined the acquirer and user system requirements. Its functions include identification of all or as many as possible software system requirements, and its conclusion marks the established requirements baseline, sometimes called the allocated baseline [3].

      Requirement Analysis

      Functional Requirement Analysis

      Non-Functional Requirement Analysis

      User Interface Transaction Performance Auditing

      Authentication

      Performance External Interface Design Constraints Quality Attributes

      Fig.2. Software Requirement Analysis We can categorize software requirements as shown in Fig.2.Functional requirements specify functions that a

      system or system component must be capable of performing.

      Non-Functional requirements, which include the Performance requirements, specify performance characteristics that a system or system component must possess such as speed, accuracy, and frequency. External interface requirements specify hardware, software, or database elements with which a system or component must interface, or set forth constraints on formats, timing, or other factors caused by such an interface. Design constraints affect or constrain the design of a software system or software system component, for example, language requirements, physical hardware requirements, software development standards, and software quality assurance standards. Quality attributes specify the degree to which software possesses attributes that affect quality, such as correctness, reliability, maintainability, and portability.

3. In software system engineering, a functional requirement defines a function of a software system or its component. A function is described as a set of inputs, the behavior, and outputs. Functional requirements may be calculations, technical details, data manipulation and processing and other specific functionality that define what a system is supposed to accomplish. Behavioral requirements describing all the cases where the system uses the functional requirements are captured in use cases. Functional requirements are supported by non- functional requirements, which impose constraints on the design or implementation, such as performance requirements, security, or reliability. Acceptable systems must satisfy all the mandatory requirements. [12]

   Functional requirements are based on the following four classical members have been depicted in Fig .3 as,

   User Interface

   Functional Requirements

   Auditing Authentication

   Fig.3. Classification of Functional Requirements.

   • Identification

   • Reaction

   • Behavior

     Transaction based performance

   • Identification

   • Reaction

   • Behavior Auditing

   • Functions

   • Limitations Authentication

   • Members

   • Managers

   • Administrators.

   1. The representation for the requirement starts from the

      world view to the design view. This may be a top down or bottom up approach. A system should be modeled, which has an element and also plays a vital role in the development process [9] [10].

      Now the modeled developed is top down approach, so it starts form

      Defining the processes

      Represent the behavior of the processes assumptions on which the behavior is based.

      Explicitly define the exogenous end endogenous input to the model.

      Represent all the links.

      In constructing a model, the restraining factors such as assumptions, simplifications, limitations and constraints must be considered.

      Representing the requirements in World view (WV) as,

      WV D1 , D2 , D3…, Dn

      D D , D , D …, D

      i 1 2 3 n

      Retrieving input from the user

      Di are the Set of domains either systems / subsystems. Representing the requirement as Domain view (DV),

      DV E1 , E2 , E3 ,…Em

      E j E1, E2 , E3 ,…, Em

      Ej are the set of elements which satisfies the objective or the goal of accomplished tasks.

      Representing the Elemental view (EV) as,

      EV C1 , C2 , C3 ,…Ck

      Ck C1, C2 , C3 ,…,Ck

      engineering plays in complex projects. An Heuristic approach which will optimize the complex problems through various techniques. These techniques and methods leads to feasible solution through LPPs. There are various methods through which optimal solution can be obtained. Like, Least cost method, North west corner rule, Traveling sales person problem[19].

      Ck are the set of technical components that achieves the necessary function of an element [3].

      These assumptions shown in Fig.4, of world, domain, elementary and components of the can be evaluated via a genetic algorithmic approach.

      World View( Requirement analysis)

      Domain View 1( Functional)

      Domain View 2(Non- Functional)

      Elementary View 1(Retreiving Input from the user)

      Elementary View2 Transaction Performance

      Elementary View 3 Auditing

      Detailed view1 Identification

      Fig. 4. A Model Representation – Functional requirements.

4. 1. Operations research supports systems engineering. The tools of operations research are used in systems analysis, decision making, and trade studies. Highlights the role systems

      Operations research, briefly, is concerned with the optimization of a process under multiple

      constraints. This pa ptimization techn hich helps to hav

      r takes into consi ue assignmen minimal time perio

      Detailed view3 Behavior

      Detailed view2 Reaction

      pe deration the

      o iq t problem,

      w e d and can achieve an approximate solution which is responsible for preparing a decision making system.

      This decision can be applied to complex programs. It is taken into consideration that constraints at various levels.

      The Assignment Problem

      The simple assignment problem which helps to optimize and reduce the cost of the product. On the basis of the output, the product will be identified to be an optimized. This will help the software organization to identify the minimum cost of the product and cost taken to complete the process.

      An assignment problem is a special type of linear programming problem where the objective is to minimize the cost or time of completing a number of jobs by a number of persons [20].

      A typical assignment problem, presented in the classic manner, is shown in Fig. 12. Here there are five customers to be assigned to five requirements. The numbers in the matrix indicate the cost of doing each requirement analysis with each module. project with costs of M are disallowed assignments. The problem is to find the minimum time to matching the requirements to products.

      Figure.5. Matrix model of the requirements.

      The network model is in Fig. 6. It is very similar to the transportation model except the external flows are all +1 or -1. The only relevant parameter for the assignment model is arc cost (not shown in the figure for clarity) ; all other parameters should be set to default values. The assignment network also has the bipartite structure.

      Figure 6. Network model of the requirements.

      The solution to the assignment problem as shown in Fig. 7 has a total flow of 1 in every column and

      row, and is the assignment that minimizes risk of the requirement analysis.

      Figure 7. Solution to the requirement optimization Problem

      so, in searching a large state-space, multi-modal state-space, or n-dimensional surface, a genetic algorithm may offer significant benefits over more typical search of Optimization Techniques. (linear programming, heuristic, depth-first, breath-first, and praxis.)

5. CONCLUSION

Software System Engineering performs a variety of functions at various stages in the product development life cycle. Software Requirement Analysis is a phase in which reevaluation has to be startd. Requirements are classified into functional and non-functional requirements relevant to the product or process developed. The functional requirements categorized as, user interface, transaction performance, auditing and authentication were done in accordance with their functions. The basic representation which is relevant to software system engineering such as world, domain, elementary and component view were discussed. The views noted have been approached from top – down. This paper focuses on using the LPP to have an iterative process of identifying and refining the requirements by a method of reevaluation. A series of repeated steps using the tool will help us to elicit all the requirements to develop the design phase successfully.

Specification

1. Quantifying Software Reliability Readiness Astana, A.; Olivieri, J. ; Alcatel – Lucent, Westford, MA, USA

2. Software Engineering a Practioners Approach, sixth Edition, Roger S.Pressman.

3. Software Engineering Theory and Practice, Fourth Edition, Shari Lawerence Fleeger, Joanne M. Atlee.

4. A. J. Chipperfield and P. J. Fleming, the MATLAB Genetic Algorithm Toolbox.

5. Richard H.Thayer, Software System Engineering: A TutorialIEEE 2002, pp 68-73.

6. Eric C.Honour, Understanding the Value of System Engineering

7. Introduction to Systems Engineering

8. Linda Westfall, Software Requirements Engineering: What, Why, Who, When, and How, 2005-2006.

9. Dr.Judith Dahmann, Importance of systems engineering in Early Acquisition.

10. www.ofnisystems.com/Validation/Functional_Req uirements.htm

11. Terry Bahill, The Eight System Engineering Documents, 2001-2009.

12. A.Terry Bahill, Frank F. Dean, What is system engineering? A consensus of senior system Engineers, Jan 15, 2009.

13. Dr. Laurie Williams, A (Partial) Introduction to Software Engineering Practices and Methods, NCSU CSC326 Course Pack, 2008-2009

    (Fifth) Editions.

14. Prof. Dr. Oscar Nierstrasz, Dr. St´ephane DucasseMichele Lanza, Recovering the Evolution of Object Oriented SoftwareSystems Using a Flexible Query Engine, June 2001.

15. Ruth Malan and Dana Bredemeyer Functional Requirements and Use Cases.

16. http://media.wiley.com/product_data/excerpt/96/ 07695119/0769511996.pdf.

17. http://businessmanagementcourses.org/Lesson19 AssignmentProblem.pdf

18. Operations Research: An Introduction (7th Edition)

    Hamdy A. Taha

19. Quantifying Software Reliability Readiness

Asthana, A.; Olivieri, J.;

Alcatel-Lucent, Westford, MA, USA