SYSTEME ANALYSIS AND DESIGN

Transcription

1 Ministry of Secondary Education Progressive Comprehensive High School & PCHS Mankon Bamenda Department of Computer Studies Republic of Cameroon Peace Work Fatherland School Year 2013/2014 SYSTEME ANALYSIS AND DESIGN Class: Comp. Sc A/L By: DZEUGANG PLACIDE Systems are created to solve problems. Systems development can generally be thought of as having two major components: Systems analysis and Systems design. System design is the process of planning a new business system or one to replace or complement an existing system. But before this planning can be done, we must thoroughly understand the old system and determine how computers can best be used to make its operation more effective. System analysis, then, is the process of gathering and interpreting facts, diagnosing problems, and using the information to recommend improvements to the system. Lesson objectives It is expected that after going through this lesson, you would be able to - Understand information system describe its components and various types of IS. - explain the different phases of system development life cycle - Understand and describe Phases of system and software Design - Learn the steps in project planning to develop a defensible plan and logical schedule. - Learn the tools needed to plan, schedule, and budget a project. - Represent timing of a project using Gantt chart, PERT chart, calculate and represent critical path Table of Contents I. DATA PROCESSING CYCLE... 2 II. INFORMATION SYSTEM What is a System? What is an Information System? Types of Information System... 5 III. INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN System analysis System design Common analysis tools IV. SYSTEM DEVELOPMENT LIFE CYCLE (SDLC) Stages of a SDLC SDLC Models Argile model V. INTRODUCTION TO PROJECT MANAGEMENT What is a project? What Is Project Management? Importance of Project Management Life cycle of a project Characteristics of a project The project management triangle Different aspects to consider Project Management tools and Techniques Visit for further learning tools for ICT & Comp. Sc Page 1 of 28

2 I. DATA PROCESSING CYCLE The term data processing (or by abuse information processing) usually refers to the manipulation off raw information (called data) to produce useful information. Information processing cycle refers to the sequence of events which includes four principal stages: Input, processing and output 1- Input: Data input refers to the various manual and automated ways by which data enter the computer. This stage involves collection of data from the outside or also from within the system. The input stage can be further broken down into data acquisition, data entry and data validation. - Data acquisition refers to the collection of the raw data from the outside so that it can be put into an Information system. - Data entry is the process of putting the acquired data into the IS. Example: typing students details into a database - Data validation refers to the process of checking the data to ensure it is error free. It uses routines also called validation routines or check routines, that check for correctness, meaningfulness and security of data that are input to the system. format check: e.g. date has to be in the format DD/MM/YY Data type check: e.g. the letter O should not be typed instead of the integer 0. Range check: The month should lie between 1 and 12 Limit check: the age should not be negative Presence check: e.g. Any customer must have a telephone number Consistency check: e.g. If Title = Mrs, then the gender = F 2- Processing : In this stage the computer processes the minutest details entered. It is the fact of manipulating data to produce information. Common processing methods Batch Processing: This is a method where the information to be organized is sorted into groups to allow for efficient and sequential processing. Online Processing: This is a method that utilizes Internet connections and equipment directly attached to a computer. It is used mainly for information recording and research. Real-Time Processing: This technique has the ability to respond almost immediately to various signals in order to acquire and process information. Distributed Processing: This method is commonly utilized by remote workstations connected to one big central workstation or server. ATMs are good examples of this data processing method. Visit for further learning tools for ICT & Comp. Sc Page 2 of 28

3 3- Output: In this stage, the processed information is now transmitted to the user. Output is the act of sending out information by a data processing system such as the computer. 4- Other stages : Other stages include: (a) Storage: After the data has been processed, along with the output to the user, the data is also stored. (b) Retrieval: This is the reverse of storage (c) Communication: This is the process of sending data or information to another places. (d) Data verification: This is the process whereby the process is checked for accuracy and inconsistencies after data migration. Data verification is used to prevent errors occurring when data is copied from one medium to another. Common data verification methods include: - Proof reading (visual check): checked for errors by looking through the data. E.g. proof-reading a typed document - Double keying: This is a check to see whether the data has been keyed in correctly. The data is keyed twice, and the computer will only accept the data for processing in the two versions are identical. - Parity: Used to check for transmission errors over network or between memory and disk. An extra bit is added to each binary number before it is transmitted. Even parity system makes sure that each number has an even number of 1 bits. After transmission each number is checked to see if it still has an even number of 1 bits. If not, then the computer will conclude that the corruption of data has occurred. (e) Archiving: Archiving means taking the data off the main storage (e.g. hard drive) and storing it offline (not immediately available) usually on tape in the way it will not take up important hard disk space. (f) Deleting: This is the process of erasing or wiping our recorder data (usually from a recorded unit). II. INFORMATION SYSTEM 1.1. What is a System? The term "System" is derived from the Greek word systema. It means an organized relationship among functioning units or components. We can define a System as a combination of resources or functional units working together to accomplish a given task. a) Basic element of a system The basic elements of the system may be listed as: Resources: Resources can be hardware, software or liveware. Procedures: Every system functions under a set of rules that govern the system to accomplish the defined goal of the system. This set of rules defines the procedures for the system Data/Information, Visit for further learning tools for ICT & Comp. Sc Page 3 of 28

4 Processes: The systems have some processes that make use of the resources to achieve the set goal under the defined procedures. b) Characteristics of a system Systems also exhibit certain features and characteristics, some of which are: Objective: Every system has a predefined goal or objective towards which it works. A system cannot exist without a defined objective. Standards: It is the acceptable level of performance for any system. Systems should be designed to meet standards. Environment: Every system whether it is natural or man made co-exists with an environment. It is very important for a system to adapt itself to its environment. Feedback: Feedback is an important element of systems. The output of a system needs to be observed and feedback from the output taken so as to improve the system and make it achieve the laid standards. Boundaries and interfaces: Every system has defined boundaries within which it operates. Beyond these limits the system has to interact with the other systems. c) Types of Systems Manual Systems: These are systems that are basically mechanical in nature and do not require or use any automation. Such systems existed predominantly in the past and were not very reliable or fast. Information Systems: (IS) Any system that makes use of automation and especially harnessed by people, procedures, software, hardware and digital data is called an information system (IS) What is an Information System? An Information System (IS) is defined as an organized collection of technical and human resources for the processing, storing and distribution of an organization s information. An IS using a computer is called a Computer Based Information System (CBIS) Components of IS The 5 components that must come together in order to produce a Computer-Based Information system are: Hardware: The term hardware refers to machinery. This category includes the computer itself, which is often referred to as the central processing unit (CPU), and all of its support equipments. Software: The term software refers to computer programs and the manuals (if any) that support them. Data: Data are facts that are used by programs to produce useful information. Visit for further learning tools for ICT & Comp. Sc Page 4 of 28

5 Procedures: Procedures are the policies that govern the operation of a computer system. "Procedures are to people what software is to hardware" is a common analogy that is used to illustrate the role of procedures in a CBIS. People: Often the most over-looked element of the CBIS are the people, probably the component that most influence the success or failure of information systems Types of Information System Information systems differ in their business needs. Also depending upon different levels in organization information systems differ. Three major information systems are: 1. Transaction processing 2. Management information system 3. Decision support system Decision support system (DSS) A decision support system is a computer application that helps users analyze problems and make business decisions more confidently. It uses data routinely collected in organizations and special analysis tools to provide information support to complex decisions. Strategic planning (DSS) Management control (MIS) Operation control (TPS) To store all the necessary decision-making data, DSSs or EISs often use extremely large databases, called data warehouses. A data warehouse stores and manages the data required to analyze historical and current business circumstances Management Information system (MIS) The MIS is defined as a system which provides information support for decision making in the organization. They use the results of transaction processing and some other information also. It is an information system that generates accurate, timely and organized information so managers and other users can make decisions, solve problems, supervise activities, and track progress. An important element of MIS system is database Transaction Processing System (TPS) A transaction processing system (TPS) is an information system that captures and processes data generated during an organization s day-to-day transactions. A transaction is any activity of an organization including a business activity such as a deposit, payment, order or reservation. As computers became more powerful, system developers built online transaction processing systems. With online transaction processing (OLTP) the computer processes transactions as they are entered. Visit for further learning tools for ICT & Comp. Sc Page 5 of 28

6 Other types of information systems a) Office Automation System (OAS): These are systems that use varied computer machinery and software to digitally create, collect, store, manipulate and relay office information needed for accomplishing basic tasks in an organisation. All office functions like dictation, typing, filing, copying, fax, telex, microfilm and records management, telephone and telephone switch board operations are included. b) Expert system (ES): An expert system is an information system that captures and stores the knowledge of human experts and then imitates human reasoning and decision-making processes for those who have less expertise. Expert systems are composed of two main components: a knowledge base and inference rules. - A knowledge base is the combined subject knowledge and experiences of the human experts. - The inference rules are a set of logical judgments applied to the knowledge base each time a user describes a situation to the expert system. c) Executive Information System (EIS): This is a computer based system intended to help and support the information and decision making needs of senior executives of a company or organization. It provides easy access to internal and external information needed to achieve the strategic goals of the organization. It is commonly considered as a specialized form of DSS. d) Integrated Information Systems (IIS): With today s sophisticated hardware, software and communications technologies, it is often difficult to classify a system as belonging uniquely to one of the information system types discussed. Although expert systems still operate primarily as separate systems, organizations increasingly are consolidating their information needs into a single, integrated information system. III. INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN System Analysis and Design (SAD) is the process of defining the architecture, components, modules, interfaces and data for a system to achieve a specific goal or satisfy specific requirements. System development can generally be thought of having two major components: systems analysis and systems design. In System Analysis more emphasis is given to understanding the details of an existing system or a proposed one and then deciding whether the proposed system is desirable or not and whether the existing system needs improvements. System design is the process of planning a new business system or one to replace or complement an existing system. Analysis specifies what the system should do. Design states how to accomplish the objective. Visit for further learning tools for ICT & Comp. Sc Page 6 of 28

7 3.1. System analysis System analysis is the process of investigating a system, identifying problems, and using the information to recommend improvements to the system What is the purpose of the analysis phase? the present system is studied in depth, and new requirements are specified We are NOT concerned with the new design here, only in determining the requirements for the new system What is a system analyst? He is the person responsible for the development of an information system. Systems analysts design and modify systems by turning user requirements into a set of functional specifications, which are the blueprint of the system. Some responsabilities of a system analyst are: Identify, understand and plan for organizational and human impacts of planned systems, and ensure that new technical requirements are properly integrated with existing processes and skill sets. Plan a system flow from the ground up. Interact with internal users and customers to learn and document requirements that are then used to produce business requirements documents. Write technical requirements from a critical phase. Interact with designers to understand software limitations. Help programmers during system development, ex: provide use cases, flowcharts or even database design. Perform system testing. Deploy the completed system. Document requirements or contribute to user manuals. Visit for further learning tools for ICT & Comp. Sc Page 7 of 28

8 3.2. System design System design is the process of planning a new business system or one to replace or complement an existing system. In the systems design phase, a new or alternative information system is designed. It consists of three tasks: Designing Alternative Systems In almost all instances, more than one design can be developed to meet the information needs. Each alternative must be checked for feasibility including: o Economic feasibility (Will the costs of the new system be justified by the benefits? How long will it take to pay for itself) o Technical feasibility: Are reliable hardware, software, and training available to make the system work, and if not, can it be obtained? o Operational feasibility: Can the system actually be made to operate in the organization, or will people employees, managers, clients resist it? Selecting the Best System Management must consider four key questions when selecting the best (optimal) system Will the system fit in the organization s overall information system? Will the system be flexible enough so it can be modified in the future? Can it be made secure against unauthorized use? Are the benefits worth the costs? Consider some criteria like reusability and portability Reuse: Using components of one product to facilitate development of a different product with different functionality A product is portable if it is significantly easier to modify it to run on another system configuration (compiler, hardware, operating system) than recode it from scratch Writing the systems design report The systems design report is prepared for higher management and describes alternate designs. It presents the costs and benefits and outlines the effect of alternate designs on the organization It concludes by recommending one of the systems 3.3. Common analysis tools Decision tables : Decision tables are used to model complicated programming logic. They can make it easy to see that all possible combinations of conditions have been considered; when conditions are missed, it is easy to see this. Visit for further learning tools for ICT & Comp. Sc Page 8 of 28

9 Example of decision table: Printer troubleshooter Conditions/ Courses of action Rules Printer does not print Y Y Y Y N N N N Conditions A red light is flashing Y Y N N Y Y N N Printer is unrecognized Y N Y N Y N Y N Check the power cable X Check the printer-computer cable X X Actions Ensure printer software is installed X X X X Check/replace ink X X X X Check for paper jam X X System flowchart: System flowchart is the graphical representation of the flow of data in the system, and represents the work process of the system. Various symbols are used in the flowchart to designate specific actions. We will use the following symbols: input process storage output For example, a system flowchart describing a program is: Here, the program Pay010 has keyboard input, and produces output on the monitor and printer Data flow diagrams The Data Flow Diagram (DFD) is a graphical representation of the flow of data through an information system. It enables you to represent the processes in your information system from the viewpoint of data. Data flow diagrams are used by systems analysts to design information-processing systems but also as a way to model whole organizations. There exist two methods to represent DFD: Gane & Sarson method and Yourdon method. Visit for further learning tools for ICT & Comp. Sc Page 9 of 28

10 Concept Gane & Sarson Yourdon Description Process Location where data is transformed. See Process. Flow Oriented link between objects, which conveys data. See Flow. Data store Repository of data. See Data store. External entity Source or destination of data. See External entity. Example: A context-level data flow diagram for an airline reservation system. IV. SYSTEM DEVELOPMENT LIFE CYCLE (SDLC) SDLC, System Development Life Cycle is a process used by software industry to design, develop and test high quality software. The SDLC aims to produce a high quality software that meets or exceeds customer expectations, reaches completion within times and cost estimates. It consists of a detailed plan describing how to develop, maintain, replace and alter or enhance specific software. The life cycle defines a methodology for improving the quality of software and the overall development process. Visit for further learning tools for ICT & Comp. Sc Page 10 of 28

11 4.1. Stages of a SDLC. A typical Software Development life cycle consists of the following stages: Stage 1: Planning and Requirement Analysis : Requirement analysis is the most important and fundamental stage in SDLC. It is performed by the senior members of the team with inputs from the customer, the sales department, market surveys and domain experts in the industry. This information is then used to plan the basic project approach and to conduct product feasibility study in the economical, operational, and technical areas. Stage 2: Defining Requirements : Once the requirement analysis is done the next step is to clearly define and document the product requirements and get them approved from the customer or the market analysts. This is done through SRS (Software Requirement Specification) document which consists of all the product requirements to be designed and developed during the project life cycle. Stage 3: Designing the product architecture : A design approach clearly defines all the architectural modules of the product along with its communication and data flow representation with the external and third party modules (if any). The internal design of all the modules of the proposed architecture should be clearly defined with the minutest of the details in DDS(Design Document Specification). Stage 4: Building or Developing the Product: In this stage of SDLC the actual development starts and the product is built. The programming code is generated as per DDS during this stage. If the design is performed in a detailed and organized manner, code generation can be accomplished without much hassle. Stage 5: Testing the Product: This stage is usually a subset of all the stages as in the modern SDLC models, the testing activities are mostly involved in all the stages of SDLC. However this stage refers to the testing only stage of the product where products defects are reported, tracked, fixed and retested, until the product reaches the quality standards defined in the SRS. Stage 6: Deployment in the Market and Maintenance : Once the product is tested and ready to be deployed it is released formally in the appropriate market. Sometime product deployment happens in stages as per the organizations business strategy. Then based on the feedback, the product may be released as it is or with suggested enhancements in the targeting market segment. After the product is released in the market, its maintenance is done for the existing customer base SDLC Models Waterfall Model This model is also known as linear sequential model. The first published model, suggests a systematic, sequential approach to software development that begins at the system level and progresses through analysis, design, coding, testing, and support. It is very simple to Visit for further learning tools for ICT & Comp. Sc Page 11 of 28

12 understand and use. In a waterfall model, each phase must be completed fully before the next phase can begin. At the end of each phase, a review takes place to determine if the project is on the right path and whether or not to continue or discard (give up, surrender) the project. In waterfall model phases do not overlap. Advantages of Waterfall model: Simple and easy to understand and use. Easy to manage due to the rigidity of the model each phase has specific deliverables and a review process. Phases are processed and completed one at a time. Works well for smaller projects where requirements are very well understood Good for management control (plan, staff, track) Disadvantages of Waterfall model: Once an application is in the testing stage, it is very difficult to go back and change something that was not well-thought out in the design/concept stage. No working software is produced until late during the life cycle. High amounts of risk and uncertainty. Not a good model for complex and object-oriented projects. Poor model for long and ongoing projects. Not suitable for the projects where requirements are at a moderate to high risk of changing. When to use Waterfall model Requirements are very well known, clear and fixed. Product definition is stable. Technology is understood. There are no ambiguous requirements Ample resources with required expertise are available freely The project is short. Visit for further learning tools for ICT & Comp. Sc Page 12 of 28

13 Iterative Model An iterative life cycle model does not attempt to start with a full specification of requirements. Instead, development begins by specifying and implementing just a part of the software, which can then be reviewed in order to identify further requirements. This process is then repeated, producing a new version of the software for each cycle of the model. Advantages of the model In iterative model we can only create a high-level design of the application before we actually begin to build the product and define the design solution for the entire product. Later on we can design and built a skeleton version of that, and then evolved the design based on what had been built. In iterative model we are building and improving the product step by step. Hence we can track the defects at early stages. This avoids the downward flow of the defects. In iterative model we can get the reliable user feedback. When presenting sketches and blueprints of the product to users for their feedback, we are effectively asking them to imagine how the product will work. In iterative model less time is spent on documenting and more time is given for designing. Disadvantages of the model Each phase of an iteration is rigid with no overlaps Costly system architecture or design issues may arise because not all requirements are gathered up front for the entire lifecycle When to use iterative model Requirements of the complete system are clearly defined and understood. When the project is big. Major requirements must be defined; however, some details can evolve with time Incremental Model The incremental model is an intuitive approach to the waterfall model. Multiple development cycles take place here, making the life cycle a multi-waterfall cycle. Cycles are divided up into smaller, more easily managed iterations. Each iteration passes through the requirements, design, implementation and testing phases. Visit for further learning tools for ICT & Comp. Sc Page 13 of 28

14 A working version of software is produced during the first iteration, so you have working software early on during the software life cycle. Subsequent iterations build on the initial software produced during the first iteration. Advantages of the model Generates working software quickly and early during the software life cycle. More flexible less costly to change scope and requirements. Easier to test and debug during a smaller iteration. Customer can respond to each built. Lowers initial delivery cost. Easier to manage risk because risky pieces are identified and handled during its iteration. Disadvantages of the model Needs good planning and design. Needs a clear and complete definition of the whole system before it can be broken down and built incrementally. Total cost is higher than waterfall. When to use Incremental model Requirements of the complete system are clearly defined and understood. Major requirements must be defined; however, some details can evolve with time. There is a need to get a product to the market early. A new technology is being used Resources with needed skill set are not available There are some high risk features and goals V-Shaped Model V-model means Verification and Validation model. Just like the waterfall model, the V- model life cycle is a sequential path of execution of processes. Each phase must be completed before the next phase begins. Testing of the product is planned in parallel with a corresponding phase of development. Visit for further learning tools for ICT & Comp. Sc Page 14 of 28

15 Requirements like BRS (Business Requirement Specification) and SRS (System Requirement Specification) begin the life cycle model just like the waterfall model. But, in this model before development is started, a system test plan is created. The test plan focuses on meeting the functionality specified in the requirements gathering. The high-level design (HLD) phase focuses on system architecture and design. It provides overview of solution, platform, system, product and service/process. An integration test plan is created in this phase as well in order to test the pieces of the software systems ability to work together. The low-level design (LLD) phase is where the actual software components are designed. It defines the actual logic for each and every component of the system. Class diagram with all the methods and relation between classes comes under LLD. Component tests are created in this phase as well. The implementation phase is, again, where all coding takes place. Once coding is complete, the path of execution continues up the right side of the V where the test plans developed earlier are now put to use. Advantages of the V-Model Simple and easy to use. Testing activities like planning, test designing happens well before coding. This saves a lot of time. Hence higher chance of success over the waterfall model. Proactive defect tracking that is defects are found at early stage. Avoids the downward flow of the defects. Works well for small projects where requirements are easily understood. Disadvantages of V-Model Very rigid and least flexible. Visit for further learning tools for ICT & Comp. Sc Page 15 of 28

16 Software is developed during the implementation phase, so no early prototypes of the software are produced. If any changes happen in midway, then the test documents along with requirement documents has to be updated. When to use V-Model The V-shaped model should be used for small to medium sized projects where requirements are clearly defined and fixed. The V-Shaped model should be chosen when ample technical resources are available with needed technical expertise Spiral model The spiral model is similar to the incremental model, with more emphasis placed on risk analysis. The spiral model has four phases: Planning, Risk Analysis, Engineering and Evaluation. A software project repeatedly passes through these phases in iterations (called Spirals in this model). The baseline spiral, starting in the planning phase, requirements are gathered and risk is assessed. Each subsequent spirals builds on the baseline spiral. Requirements are gathered during the planning phase. In the risk analysis phase, a process is undertaken to identify risk and alternate solutions. A prototype is produced at the end of the risk analysis phase. Software is produced in the engineering phase, along with testing at the end of the phase. The evaluation phase allows the customer to evaluate the output of the project to date before the project continues to the next spiral. Advantages of the spiral model High amount of risk analysis hence, avoidance of Risk is enhanced. Good for large and mission-critical projects. Strong approval and documentation control. Visit for further learning tools for ICT & Comp. Sc Page 16 of 28

17 Additional Functionality can be added at a later date. Software is produced early in the software life cycle. Disadvantages of the spiral model Can be a costly model to use. Risk analysis requires highly specific expertise. Project s success is highly dependent on the risk analysis phase. Doesn t work well for smaller projects. When use the spiral model When costs and risk evaluation is important For medium to high-risk projects Long-term project commitment unwise because of potential changes to economic priorities Users are unsure of their needs Requirements are complex New product line Significant changes are expected (research and exploration) Argile model Agile SDLC model is a combination of iterative and incremental process models with focus on process adaptability and customer satisfaction by rapid delivery of working software product. Agile Methods break the product into small incremental builds. These builds are provided in iterations. Each iteration typically lasts from about one to three weeks. In software development, the agile model does not build an entire system at once, but rather develops incrementally. Less time is invested upfront for documenting requirements when development is done incrementally. Another characteristic of agile software development is that customer feedback occurs simultaneously with development Advantage of agile model Is a very realistic approach to software development Promotes teamwork and cross training. Functionality can be developed rapidly and demonstrated. Resource requirements are minimum. Suitable for fixed or changing requirements Delivers early partial working solutions. Visit for further learning tools for ICT & Comp. Sc Page 17 of 28

18 Good model for environments that change steadily. Minimal rules, documentation easily employed. Enables concurrent development and delivery within an overall planned context. Little or no planning required Easy to manage Gives flexibility to developers Disadvantages of argile model Not suitable for handling complex dependencies. More risk of sustainability, maintainability and extensibility. An overall plan, an agile leader and agile PM practice is a must without which it will not work. Strict delivery management dictates the scope, functionality to be delivered, and adjustments to meet the deadlines. Depends heavily on customer interaction, so if customer is not clear, team can be driven in the wrong direction. There is very high individual dependency, since there is minimum documentation generated. Transfer of technology to new team members may be quite challenging due to lack of documentation RAD model Rapid application development (RAD) is a software development methodology that uses minimal planning in favor of rapid prototyping. The "planning" of software developed using RAD is interleaved with writing the software itself. The lack of extensive pre-planning generally allows software to be written much faster, and makes it easier to change requirements. The phases in the rapid application development (RAD) model are: Business modeling: The information flow is identified between various business functions. Data modeling: Information gathered from business modeling is used to define data objects that are needed for the business. Process modeling: Data objects defined in data modeling are converted to achieve the business information flow to achieve some specific business objective. Description are identified and created for CRUD of data objects. Application generation: Automated tools are used to convert process models into code and the actual system. Testing and turnover: Test new components and all the interfaces. Visit for further learning tools for ICT & Comp. Sc Page 18 of 28

19 Advantages of the RAD model: Reduced development time. Increases reusability of components Quick initial reviews occur Encourages customer feedback Integration from very beginning solves a lot of integration issues. Disadvantages of RAD model: Depends on strong team and individual performances for identifying business requirements. Only system that can be modularized can be built using RAD Requires highly skilled developers/designers. High dependency on modeling skills Inapplicable to cheaper projects as cost of modeling and automated code generation is very high. When to use RAD model: RAD should be used when there is a need to create a system that can be modularized in 2-3 months of time. It should be used if there s high availability of designers for modeling and the budget is high enough to afford their cost along with the cost of automated code generating tools. RAD SDLC model should be chosen only if resources with high business knowledge are available and there is a need to produce the system in a short span of time (2-3 months). Visit for further learning tools for ICT & Comp. Sc Page 19 of 28

20 Prototype model Prototyping is the process of building a model of a system. The basic idea here is that instead of freezing the requirements before a design or coding can proceed, a throwaway prototype is built to understand the requirements. In terms of an information system, prototypes are employed to help system designers build an information system that intuitive and easy to manipulate for end users. Prototyping is an iterative process that is part of the analysis phase of the systems development life cycle. A prototype is an original type, form, or instance of something serving as a typical example, basis, or standard for other things of the same category. With rare exceptions, multiple iterations of prototypes are used to progressively refine the design. Diagram of Prototype model: Advantages of Prototype model: Users are actively involved in the development Since in this methodology a working model of the system is provided, the users get a better understanding of the system being developed. Errors can be detected much earlier. Quicker user feedback is available leading to better solutions. Missing functionality can be identified easily Confusing or difficult functions can be identified Requirements validation, Quick implementation of, incomplete, but functional, application. Disadvantages of Prototype model: Can lead to insufficient analysis. Practically, this methodology may increase the complexity of the system as scope of the system may expand beyond original plans. Incomplete application may cause application not to be used as the full system was designed Incomplete or inadequate problem analysis. When to use Prototype model: Visit for further learning tools for ICT & Comp. Sc Page 20 of 28

21 Prototype model should be used when the desired system needs to have a lot of interaction with the end users. Typically, online systems, web interfaces have a very high amount of interaction with end users, are best suited for Prototype model. They are excellent for designing good human computer interface systems Object modelling Object-oriented modeling is an approach to modeling an application that is used at the beginning of the software life cycle when using an object-oriented approach to software development. The software life cycle is typically divided up into stages going from abstract descriptions of the problem to designs then to code and testing and finally to deployment. Modeling is done at the beginning of the process. Object-oriented modeling is typically done via use cases and abstract definitions of the most important objects. The most common language used to do object-oriented modeling is the Unified Modeling Language (UML) Methods of interacting with a system. There are various methods used by users to interact with the system: command language: A human-computer interaction method where users entered explicit statements into a system to invoke operations. Menu: A human-computer interaction method where a list of system options is provided and a specific command is invoked by user selection of a menu option Form: A highly intuitive human-computer interaction method whereby data fields are formatted in a manner similar to paper based forms. Object: A human computer interaction method where symbols are used to represent command or functions. Natural language: A human-computer interaction method whereby inputs to and outputs from a computer base application are in conventional speaking language such as English. V. INTRODUCTION TO PROJECT MANAGEMENT 5.1. What is a project? A project is a temporary endeavor undertaken to create a unique product or service. A project is temporary in that it has a defined beginning and end in time, and therefore defined scope and resources. A project is unique in that it is not a routine operation, but a specific set of operations designed to accomplish a singular goal. Projects are undertaken at all levels of the organization. They may involve a single person or many thousands. Their duration ranges from a few weeks to a few years. Example of project: rearranging your office, installing software on your computer, writing and publishing an article/book Visit for further learning tools for ICT & Comp. Sc Page 21 of 28

22 5.2. What Is Project Management? Project management is the application of knowledge, skills and techniques to execute projects effectively and efficiently in order to meet or exceed stakeholders needs and expectations. A stakeholder is anybody who can affect or is affected by an organization, strategy or project. They can be internal or external and they can be at senior or junior levels. The project team manages the various activities of the project, and the activities typically involve: Competing demands for: scope, time, cost, risk, and quality. Managing expectations of stakeholders. Identifying requirements. The Project managers is the person responsible for supervising a system project from its initiation to its completion. Project managers can have the responsibility of the planning, execution, and closing of any project, typically relating to construction industry, engineering, architecture, computing, and telecommunications Importance of Project Management The need for project management is becoming increasingly apparent in the world today. Speed, quality, and cost control are taking on increased significance in business, government, and nonprofit sectors. Some importance of project management are: - It allows managers to plan and manage strategic initiatives that generate new revenue in expanding sectors of the market. - Project management tools decrease time to market, control expenses, ensure quality products, and enhance profitability. - It helps to sell products and services by positively differentiating them from their competitors. - It is one of the most important management techniques for ensuring the success of an organization Life cycle of a project The activities related to a project can be structured and grouped by the main aim of the activities and groups of activities. These groups of activities are linearly ordered and are called stages. Normally the life cycle of the project consists of the following stages: Initiation, Planning, Execution, Controlling and Closure The division of stages into activities depends on the type and volume of the project. We list the activities that are present in most of the projects Visit for further learning tools for ICT & Comp. Sc Page 22 of 28

23 Project initiation: determination of the main objective and forming a clear understanding about the necessity and suitability of the project; this stage should answer the questions what? and why?: Identification and initial analysis of the business needs. Determination of the main objective(s). Resource analysis (people, equipment, financial; needs and availability ). Composition of the project charter. Project planning : determination of an optimal scheme/algorithm for project execution; this stage should answer the question how? Needs analysis. Description of the project (incl. determination of activities and necessary resources). Composition of a project plan. Planning and performing necessary PR-activities. Project execution: achieving the project objectives without violating the constraints of the project: Starting up the execution. Day-to-day management. Change management and reporting. Project controlling: Project managers will compare project status and progress to the actual plan, as resources perform the scheduled work. During this phase, project managers may need to adjust schedules or do what is necessary to keep the project on track. Closing the project: formal completion of the project and building solid bases for follow-up activities: Product acceptance and implementation/application activities. Composition of the final report and the Lessons Learned document. Planning the follow-up activities (including PR activities). Filing and archiving the project documentation Characteristics of a project The objective and its formulation should be understandable for customers and adequate, reflecting the most signifcant aspects. It is recommended to apply the SMART principle. According to this, the objective and its formulation should be: Simple. Everybody who has basic knowledge of the area should understand what exactly the project is aiming to complete. Measurable. It should be possible to measure to what extent the project goal has been achieved. Agreed. The outcome should meet the customers/end users needs, should solve some problems. Realistic. The objective should correspond to the resources (incl knowledge) available. One should not plan outcomes or activities that require much more knowledge than the project team actually has; this can cause an unexpected need to perform additional research or education. Timed. Is a planned duration sufficient for achieving the project goal? What possible compensation mechanisms are available, in case unexpected delays will occure? Visit for further learning tools for ICT & Comp. Sc Page 23 of 28

24 5.6. The project management triangle Like any human undertaking, projects need to be performed and delivered under certain constraints. Traditionally, these constraints have been listed as "scope," "time," and "cost". These are also referred to as the "project management triangle", where each side represents a constraint. One side of the triangle cannot be changed without affecting the others. A further refinement of the constraints separates product "quality" or "performance" from scope, and turns quality into a fourth constraint. The time constraint refers to the amount of time available to complete a project. The cost constraint refers to the budgeted amount available for the project. The scope constraint refers to what must be done to produce the project's end result. These three constraints are often competing constraints: increased scope typically means increased time and increased cost, a tight time constraint could mean increased costs and reduced scope, and a tight budget could mean increased time and reduced scope Different aspects to consider While working on a project, many aspects should be considered. Here are some aspects among others: Project Scope Management describes the processes required to ensure that the project includes all the work required, and only the work required, to complete the project successfully. It consists of initiation, scope planning, scope definition, scope verification, and scope change control. Project Cost Management describes the processes required to ensure that the project is completed within the approved budget. It consists of resource planning, cost estimating, cost budgeting, and cost control. Project Time Management describes the processes required to ensure timely completion of the project. It consists of activity definition, activity sequencing, activity duration estimating, schedule development, and schedule control. Project Quality Management describes the processes required to ensure that the project will satisfy the needs for which it was undertaken. It consists of quality planning, quality assurance, and quality control. Project Risk Management describes the processes concerned with identifying, analyzing, and responding to project risk. It consists of risk management planning, risk identification, qualitative risk analysis, quantitative risk analysis, risk response planning, and risk monitoring and control Project Management tools and Techniques Project management is a challenging task with many complex responsibilities. Fortunately, there are many tools available to assist with accomplishing the tasks and executing the responsibilities. Some require a computer with supporting software, while others can be used Visit for further learning tools for ICT & Comp. Sc Page 24 of 28

25 manually. Project managers should choose a project management tool that best suits their management style. No one tool addresses all project management needs. Program Evaluation Review Technique (PERT) and Gantt Charts are two of the most commonly used project management tools and are described below. Both of these project management tools can be produced manually or with commercially available project management software Gantt Chart Gantt charts (or a bar chart, first used in 1917 by Henry Gantt) are used to show calendar time task assignments in days, weeks or months. The tool uses graphic representations to show start, elapsed, and completion times of each task within a project. Gantt charts are ideal for tracking progress. To draw up a Gantt chart, follow these steps: 1) List all activities in the plan. For each task, show the earliest start date, estimated length of time it will take, and whether it is parallel or sequential. If tasks are sequential, show which stages they depend on. 2) Head up graph paper with the days or weeks through completion. 3) Plot tasks onto graph paper. Show each task starting on the earliest possible date. Draw it as a bar, with the length of the bar being the length of the task. Above the task bars, mark the time taken to complete them. 4) Schedule activities. Schedule them in such a way that sequential actions are carried out in the required sequence. Ensure that dependent activities do not start until the activities they depend on have been completed. Benefits of using a Gantt chart include: Gives an easy to understand visual display of the scheduled time of a task or activity. Makes it easy to develop "what if" scenarios. Enables better project control by promoting clearer communication. Becomes a tool for negotiations. Shows the actual progress against the planned schedule. Can report results at appropriate levels. Allows comparison of multiple projects to determine risk or resource allocation. Rewards the project manager with more visibility and control over the project PERT Chart and Critical Path A PERT chart is a project management tool used to schedule, organize, and coordinate tasks within a project. PERT stands for Program Evaluation Review Technique, a methodology developed by the U.S. Navy in the 1950s to manage the Polaris submarine missile program. A similar methodology, the Critical Path Method (CPM) was developed for project management in the private sector at about the same time. Visit for further learning tools for ICT & Comp. Sc Page 25 of 28

26 Calculating of critical path To calculate the critical path, the following four parameters are determined for each activity: Earliest start date (ES): The earliest time at which the activity can start, based on the constraints and dependencies for the activity. Earliest finish date (EF): The earliest start time for the activity plus the time required to complete the activity. Latest finish date (LF): The latest time at which the activity can be completed without delaying the plan, based on the constraints and dependencies for the activity. Latest start date (LS): The latest finish time minus the time required to complete the activity Based on these dates, the slack or float for an activity is calculated. The slack for an activity is the time between its earliest and latest start time, or between its earliest and latest finish time. The slack represents the amount of time that an activity can be delayed past its earliest start or finish without extending the finish date of the longest path in the plan. If the slack is zero, the task or activity is critical and is highlighted in the Gantt chart view. On the critical path, none of the activities have slack, that is, for all these activities, ES=LS and EF=LF. A delay in an activity on the critical path delays the project. To accelerate a delayed project, reduce the total time required for the activities on the critical path. A work item without dependencies can be critical in the following situations: The duration of the work item is equal to the longest path in the plan The work item finish date, which is calculated from the remaining time, is equal to the finish date of the longest path in the plan; for example, due to a Start no earlier than constraint The same user is fully assigned to one or more tasks whose remaining time is equal to or longer than the longest path in the plan During project execution, the critical path can change. Delays in activities outside of the critical path can affect the project finish date and cause those activities to be on the critical path. Some important terminologies PERT event: a point that marks the start or completion of one or more activities. It consumes no time and uses no resources. predecessor event: an event that immediately precedes some other event without any other events intervening. successor event: an event that immediately follows some other event without any other intervening events. PERT activity: the actual performance of a task which consumes time and requires resources. A PERT activity cannot be performed until the predecessor event has occurred. Visit for further learning tools for ICT & Comp. Sc Page 26 of 28

27 optimistic time (O): the minimum possible time required to accomplish a task, assuming everything proceeds better than is normally expected pessimistic time (P): the maximum possible time required to accomplish a task, assuming everything goes wrong (but excluding major catastrophes. most likely time (M): the best estimate of the time required to accomplish a task, assuming everything proceeds as normal. expected time (T E ): the best estimate of the time required to accomplish a task, accounting for the fact that things don't always proceed as normal (the implication being that the expected time is the average time the task would require if the task were repeated on a number of occasions over an extended period of time). T E = (O + 4M + P) 6 Application Exercise: A project has been defined to contain the following list of activities along with their required times for completion: Activity No Activity Expected completion time Dependency A Requirements collection 5 - B Screen design 6 A C Report design 7 A D Database design 2 B,C E User documentation 6 D F Programming 5 D G Testing 3 F H Installation 1 E,G a) Draw a Gantt chart for the activities. b) Draw a PERT chart for the activities. c) Calculate the earliest expected completion time. d) Show the critical path. Solution a) Gantt chart Activity No A B C D E F G H Visit for further learning tools for ICT & Comp. Sc Page 27 of 28

28 b) Pert chart c) Calculate the earliest expected completion time. Using information from the table, indicate expected completion time for each activity. Calculate earliest expected completion time for each activity (T E ) and the entire project. Hint: the earliest expected completion time for a given activity is determined by summing the expected completion time of this activity and the earliest expected completion time of the immediate predecessor. Rule: if two or more activities precede an activity, the one with the largest T E is used in calculation (e.g., for activity 4, we will use T E of activity 3 but not 2 since 12 > 11). d) Show the critical path. The critical path represents the shortest time, in which a project can be completed. Any activity on the critical path that is delayed in completion, delays the entire project. Activities not on the critical path contain slack time and allow the project manager some flexibility in scheduling. Visit for further learning tools for ICT & Comp. Sc Page 28 of 28