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Note for System Analysis and Design - SAD by Hariom Sharma

  • System Analysis and Design - SAD
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Q) Explain the term:- a) Object modeling this model development the static structure from of data used in a system.Object modeling is a modeling language based on a standardized set of symbols and ways of arranging them to model on object oriented software design or system design. Some organist ion uses them Ex: - testing in combination with an S/W development Methodology. To process from initial specification to an implementation plan and to communicate. That plan to an entire term of developers. Because a modeling language is visual and at a high level of abstraction. Than code, using model encourages the generation of a shared vision that may prevent problem of interpretation latter in development often software modeling tools are used to construct. These models. Which may they be capable of Automatic transaction of code? Some methodologist identify three roughly chronological generation of object modeling notations. First generation: - In the first generation, isolated methodology and small groups developed techniques that solved problem. They saw firsthand in object oriented devolvement projects. The first-Generation include technique such as : Booch method  Class- Responsibility-collaboration card. (CRC)  Object modeling technique (OHT)  Object oriented software engineering (OOSE) st The 1 Generation languages were to developed and very closely tied with specific object-oriented Methodologies. Usually st with the same name 1 was often difficult to determine whether the notation or methodology. ->Second generation. The second generation recognized that many best practices were scattered among the fragmented object oriented methodology language several attempts where mode together practices into where not frame works such as FUSION. ->Third generation. The third generation consists of credible attempts of single industry-standard language. With unified modeling language standardizing the model was recognized. c) Dynamic modeling: - Dynamic modeling is modeling of process over time in dynamic modeling new attributes are computed as a function of attribute changes over time. The dynamic models inspired by the process – based ontology of QPT, However, since QPT was developed mainly for lumped object-based model, the concept have been modified. The dynamic model capture control, that aspect of a system that describes the sequence of operations that occur without regard for what the operation do what they operate on, or how they are implemented. The dynamic model is represented graphically with state diagram. Each state diagram shows the state and event sequences permitted in a system for one class of object. State diagrams also refer to the other r model. b) Function modeling:-A function modeling is a structured representation of the functions, activities process within the modeled system or subject area. This model describes the computational structure of the system. and also describe the transformation of value of the system. Function is invoked as action in dynamic model and operation in the object model. the model show what has to be done by a system. A function model also called an activity model or process model is a graphical representation of an enterprises function with a defined scope. The purpose for the function model are to describe the functions and processes, assist with discovery of information needs, and help identify opportunities. And establish a basis for determining product & service cost. Because, functional modeling applies to every Manpower made system it can be used in any field that deals with such system. The system being modeled can be an electronic device. Ex: - the process control system in a sugar predicting factory, customer-service activities in a bank, a robot or the entire interned. Function modeling has been used to describe function of human machine systems, to perform diagnosis and planning in industrial products and to identify failures and there consequence in such plants, recent research has been concentrated on using functional modeling methods to built supervision system, to redesign mechanical system. To describe real –time control system. To improve & automated Existing failure analysis method, and to find a method to predict and indentify hidden failure in control system. Q) What is a case tool? Why are they unable to mitigals s/w crysis? How is it used in design phase? Or How case tools support SDLC? Briefly describe the relational tool and also list down the various design activity occupied by this case tool. Or Write a brief description of case tools. How they are use full in s/w development life cycle. Write some example of case tool. Ans: - CASE stands for computer aided Software engineering. A case tool is a computer-based product coned at supporting one or more s/w engineering activities within an s/w development process. Although, ideally a case tool should support all the activities of s/w engineering process. Starts from requirement analysis to designing, coding, listing, implementation and documentation. In reality CASE tools often support one activity or at least a group of related activities.  Use of CASE tools by organization. The following are some of the ways in which CASE tools are used i) To facilitate single design methodology.

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CASE tools helps organization to standardize the development process. It also facilitates. Co-ordinate development. Integration becomes easy as common methodology is adapted. ii) Rapid Application Devolvement organization use CASE tool to improve the speed and quality of system development. iii) Testing: - CASE tools help to easy and improve testing process through automated checking and simply program maintenance. iv) Documentation: - CASE tools improve the quality and uniformity of documentation at various stages of SDLC. It also ensures the completeness of documentation. v) Project management: - It improves project management activity and to some extent automates various activities evolving in project management. vi) Productivity & reduction of cost. USE of CASE tools makes the s/w easy to maintain & hence reduce the maintenance cost Automation of various activities of system development and management processed increase productivity of the devlopementation.  ROLE OF CASE TOOL. Case tool play a major role in the following activities. I).Project management. ii).Data dictionary. iii) Code generation. Iv) User interface design. v).Schema generation. vi).Creating of Meta data type for datawerehouse. Vii) Reverse engineering. Viii) Re- engineering. Ix) Document generation. x) Version control. Xi).00 analysis and design. Xii) S/w testing. Xiii) Data modeling. Xiv) Project scheduling. Xv) Cost estimation. Advantages of CASE tools. Following are the advantages in CASE tool. i) Integrated development environment. CASE tools provide unique user interface for the developer and analyst. Automate time consuming and various activities like code generation. ii) In development CASE tools provides common platform for all the developer and helps methodical system development. iii) Consistency b/w the model and documentation. Document is the generated out of the model. CASE automatically leading to consistency b/w the model and documentation. Disadvantage of case tools. i) Complex functionality. ii) Many project management problems are not amenable to automation Hence CASE cannot be used in sub cases. Types of case tool. i) Planning and management tools: - Being the development process with informs planning & project management. ii) Analysis tools: - These tools ensure that business requirements are correctly captured during the analysis phase early in development process. Analysis tools are used to check for incomplete, inconsistent or incorrect specification. iii) Design toolset: - It provides details specification of the system. iv) Information integrator: - It integrates system specification and checks them for consistency and completeness. It also records them in CASE repository. v) Code generator: - It automatically generates code specific to a language based on the system specification. vi) Data base design toolset: - It suggests data base design and generates. System control information. vii) User interface generator: - It generates user interface based on system specification. viii) Report generator: - It generates report based on specification.

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Classification of case tool. i) Development tools: - These tools are interactive in nature. They are used for design support and code generation. ii) Front-enumerated tools: - The support activities early in the life cycle of an s/w development process. Ex: - DFD, Data Structure Design, E-R Diagram, prototype tools etc. iii) Back-enumerated tools: - they support activities in the life cycle of s/w development process. Ex: - Program flowchart, program editor, debugger code generator. iv) Horizontal tools: - Those tools are not specific to a particular life cycle step but are common across a no of life cycle steps. Ex: - Documentation tool. v) Vertical tool: - These tools are specific to life cycle. Q) What is the purpose of upper case tool and lower case tool? And how case tool support SDLC Explain with example. Ans: - Dependency on the phase in which the case tool are used. They can be classified into two main types these are:a) Upper case tool b)Lower case tool  Upper case tool are designed to support the information planning. And the project identification and selection, project initiation and planning, analysis and design phase of the system development life cycle.  Lower case tool are designed to support the implementation and maintenance phased of the system development life cycle. Types of case tool. There are following types of case tool. i) Analysis tools: - These are the tools that help check incomplete tools that help check incomplete inconsistent or incorrect specification in diagram, forms and reports. ii) Diagrammatic tools: - This tool enables the system developers to represent process data and control structure graphically. iii) Display and report generator: - These tools help to plan and so how the system will look to the user the format and layout of form and reports are designed using these tools. They help the designer to visually design screen, menus, reports, dialog boxes and other components of the system. iv) Code generator: - These are the tools that grate programs and database definition using the Information given in diagram, form, and reporter other specification. v) Documentation generators: - These are the tool that helps in automatic creation of technical and user documentation in standard format. vi) Testing and debugging tools: - These tools help in testing and correcting programs. How case tool support SDLC explains CASE tools can assist analysts in the SDLC.  Provide a repository to store information on each of the phases - excellent for comprehensive documentation of the development process.  Diagraming tools assist in analyst/user communications. For example, Data Flow Diagrammer and E-R Model Diagrammer.  Provide project management capabilities including maintenance management - impact analysis. However, each CASE tool supports a specific implementation of an SDLC; often in a very ridged fashion. Upper CASE Tools typically focus on the first 5 steps of the SDLC. Lower CASE Tools focus on steps 4-6 and include code generation capabilities. Integrated CASE Tools cover all of the steps. SOFTWARE SELECTION:The selection of hardware and software play the role for the application development this is very time consuming process it is the process for the developer to select the requirement set of hardware or software among the varieties available in the market. So these are following feature which should considered during system selection. 1. Define of system capabilities in the terms of recruitment. 2. Very well aware about the magnitude of the problem. 3. Must be well known about the users and performance of the system. The length of time for the system selection. 4. Increased over head due to the hardware in terms of numbers of user recruitment process recruitment and memory recruitment. The selection of system involves following steps:1) Recruitment analysis phase: - Clarity and understand the recruitment of the customer. 2) System Specification: - includes objective of the system, inputting recruitment and file structure and cost. 3) Request for proposal: - After defining the system specification the system specification this proposed specification must be delivered to the analyzed to resource the correct specification. 4) Evolution and validate: - the system analyzed must by to evolutes the specification prior to the recruitment to the customer. 5) Vendor Selection: - After validating the specification the next job o the analyst to select the vendor whose credit is good and who is well aware about the supplement of goods and maintained. 6) Criteria for Software selection :- There are following characteristics for software selection :a. Reliability b. Functionality

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c. Capacity d. Flexibility e. Usability f. Security g. Performance h. Service arability i. Ownership j. Minimal cost. 1. Functionality: - The software should be able to give response according to the functioning specification of the input. 2. Reliability: The externs which define for how long time the software will provide the rest function to the user. 3. Capability: - This feature refers that weather the software should be capable to give the current output even with the introducing of the invalid inputs. 4. Flexibility: whether the software allow the changes in it or not. 5. Usability: - weather the software is user friendly or not. 6. Security :weather the software have provision to secure the sensitive data or not 7. Performance: - whether the software is capable to given quick response effencenty or economically in gains of input. 8. Service arability :- whether the software allow the easier mutability of not 9. Ownership: - the ownership of the software is dedicated to single person or not. 10. Mina cost.: whether the software is cost effective or economic or not according to their function SOFTWERE MODEL Q) 1) RAD model:Rapid application development (RAD) model is a linear sequential s/w development process model. The emphasis is on extremely development cycle. The word “rapid” itself suggest a high speed model. In fact, a functional system is available within 60 to 90 days. Using this approach, the following faces from the RAD model. 1).Business molding 2)Data molding 3).Process molding 4)Application generation 5) Testing and turnover In this approach a separate team addresses each major function. Then these function are integrate to a form a whole this model is not appropriate to all application. When a system cannot be properly modulated. RAD will be problematic also if high perform/or high technical risk are involve them. RAD is not ideal. RAD necessarily required a committed rapid-fire team otherwise the project will fail to save on time RAD emphasis the development of program components. Objectives of RAD are:a) Actively involves system users in the analysis, design and construction activities. b) Organized system development to a series of focused intense workshop jointly involving system owners. User analyst, designer and builders. c) Accelerate the requirement analysis and design phases through an iterative construction approach. d) Reduce the amount of time until the users begins to see a working system. Advantages of RAD approach are:a) It is useful for project in which user requirements are uncertain or imprecise. b) It encourages active user and management participation (as opposed to a passive reaction to non working system model). This increase enumerated-user enthusiasm for the project. c) Projects have higher visibility and support because of the extensive user enrolment throughout the process. d) Users and management see working s/w best solution more rapidly than in model driven development. e) Errors and omissions tend to be detected earlier in prototype then in system model. f) Testing and training is a natural byproduct of the underplaying prototyping approach. g) The iterative approach is more “natural” fit because change is an expected factor during development. h) It reduced risk because you test the technical solution iteratively instead of making a whole sale commitment to any solutions. i) RAD is most popular for smaller system projects. Disadvantage of waterfall model:a) The model is linear, rigid and monolithic. b) In practice, linear progression is very tiresome and any mistake found at a large stage may need rework from the beginning stage.

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