Nile University System Analysis and Design Lecture Notes PDF

Course Code: SEN309 Course Name: System Analysis and Design Lecture Slides, Compiled & Presented By Abdulsalam Shettima Nur Lecturer, Software Engineering Department, NUN. [email protected] Teams...

Course Code: SEN309 Course Name: System Analysis and Design Lecture Slides, Compiled & Presented By Abdulsalam Shettima Nur Lecturer, Software Engineering Department, NUN. [email protected] Teams Username: Abdulsalam Nur 1  Course Content: System Concept; System Development Life Cycle Analysis: Fact gathering Techniques, data flow diagrams, Process description data modeling. System Design: Structure Charts, form designs, security, automated Tools for design. 2  Reference Textbooks 1) Systems Analysis and Design by Kenneth E. Kendall & Julie E. Kendall (10th Edition, 2019). 2) Modern Systems Analysis and Design by Jeffrey A. Hoffer, Joey F. George, and Joseph S. Valacich (9th Edition, 2020). 3) Systems Analysis and Design in a Changing World by John W. Satzinger, Robert B. Jackson, and Stephen D. Burd (7th Edition, 2015). 4) Systems Analysis and Design with UML by Alan Dennis, Barbara Haley Wixom, & David Tegarden (6th Edition, 2015). 5) Essentials of Systems Analysis and Design by Joseph S. Valacich, Joey F. George, and Jeffrey A. Hoffer (6th Edition, 2014). 3  Course Grading Policy Method Percentage Attendance 5% Group Mini-Project 10% Quiz 5% Midsemester Exam 20% Final Exam 60% Total Scores 100% 4  Caution ✓The course is 3 credit units. ✓The course is a core course. ✓Attending class & signing attendance is very important. ✓Taking note is also important. ✓The course is very bulky. ✓Group discussions are very important. ❑Disruptive Behavior: side conversations, use of electronic devices or other distracting activities during lectures are generally disliked. 5  The aim of this Course ✓The aim of this course is to provide students with a foundational skills needed to transform real-world problems into well-structured software solutions. ✓This course will explore and provide students with the tools, techniques, and frameworks necessary to build effective, efficient, and maintainable software systems that meet user requirements and industry standards. ✓Eventually, is to enable students to design high-quality, user-centric software solutions that meet project goals, perform efficiently, and are easy to maintain over time. 6 Introduction To System Analysis & Design 7  Objectives: Upon Completion of this section, you will be able to: ▪ Understand the concept of SAD. ▪ Understand the concept of systems. ▪ Explain the Characteristics of a System. ▪ Elaborate on the elements of a system. ▪ Describe the types of system. 8  What is System Analysis and Design (SAD)? ✓Systems analysis and design refers to the process of examining a business situation with the intent of improving it through better procedures and methods. ✓SAD is a process used in software engineering and information systems to identify, understand, and create efficient and effective systems. It involves the study and breakdown of systems to improve, automate, or create new ones to meet specific needs. ✓System Analysis and Design (SAD) mainly focuses on: Systems Processes Technology. ✓Systems development can generally be thought as having two major components: Systems Analysis and Systems Design. 9  Overview of System Analysis ✓System analysis is a process of analysing the existing system in order to gather the data that determines the scope, functionality and focus of the proposed system. ✓Systems Analysis it is a process of collecting and interpreting facts, identifying the problems, and decomposition of a system into its components. ✓Systems analysis is the process of gathering and interpreting facts, diagnosing problems and using the information to recommend improvement to the system. 10  System Analysis Cont… ✓System analysis is conducted for the purpose of studying a system or its parts in order to identify its objectives. ✓It is a problem-solving technique that improves the system and ensures that all the components of the system work efficiently to accomplish their purpose. 11  Overview of System Design ✓Systems Design: It is a process of planning a new business system or replacing an existing system by defining its components or modules to satisfy the specific requirements. Before planning, you need to understand the old system thoroughly and determine how computers can best be used in order to operate efficiently. ✓System Design focuses on how to accomplish the objective of the system. ❑In short-term, we can say that analysis specified what the system should do. While, design states how to accomplish the objectives. 12  What is a System? ✓To understand System Analysis and Design, one has to first understand what exactly are systems. ✓The word System is derived from Greek word Systema, which means an organized relationship between any set of components to achieve some common objective. A system is “an orderly grouping of interdependent components linked together according to a plan to achieve a specific goal.” ✓We can define a System as a combination of resources or functional units working together to accomplish a given task. ✓However, A system is made up of several components which integrate together to function and fulfil a task. ✓A system is simply a set of components that interact to accomplish some purpose. 13  example of systems ✓ Systems can be found in various domains, including natural, social, and technological environments. In the context of information systems, a system typically refers to a set of interrelated components that collect, process, store, and distribute information to support decision making, coordination, control, analysis, and visualization within an organization. ✓ For example, human body is a biological system (digestive system). We experience physical sensations by means of a complex nervous system, a set of parts, including brain, spinal cord, nerves, and special sensitive cells under our skin, that work together to make us feel hot, cold, itchy, and so on. ✓ The education systems. Each education system contains educational institutes like preparatory schools, middle and high schools and colleges. It also contains governing bodies, people (teachers and students) and some commercial bodies, which fulfill the other needs like stationery, transportation, furniture, etc. ✓ An organization may also be viewed as a system where all the employees interact with each other and also with the employer to make the organization a functional unit. The organization also interacts with their customers to make a complete business system. More examples, traffic management system, payroll system, automatic library system, human resources information system, Airline & Railway Reservation System, Electricity Supply System, 14 Judiciary System and many more.  Characteristics of a System The characteristics of a system can be generalized as follows: 1. Core objective: Core objective system has a core objective or purpose which needs to be fulfilled. It is on the core objective that the entire system is built or designed. 2. Interdependence: All the components or subsystems of a system are interdependent. The system can only function successfully when all their individual components function properly and provide input or output to each other. Interdependence means that component of the organization or computer system depends on one another. They are coordinated and linked together in a planned way to achieve an objective. 3. Integration: The entire system as a whole is weaved together as one for the procurement of desired output. This is because all the subsystems are integrated together. Integration is concerned with how a system is tied together. It means that parts of the system work together within the system even though each part performs a unique function. Successful integration will typically produce a better result as a whole rather than if each component works independently. 15  Characteristics of a System cont… 4. Interaction: Interaction refers to the procedure in which each component functions with other components of the system. All the subsystems in a system have a mutual interdependence on each other. Therefore, they need to interact with each other, as the change or process in one will affect the other subsystem also. 5. Organization: Organization implies structure and order. It is the arrangement of components that helps to achieve objectives. The system is laid out according to the manner in which the work flows. It also facilitates communication flow and command chain conduciveness. The attainment of objectives in an efficient manner is ensured. 16  Elements of a System The following elements are essentially required to build a system: 1) Inputs 2) Processor 3) Control 4) Environment 5) Output 6) Feedback 7) Boundaries/ Interface 17  1. Inputs Inputs are the information that enters into the system for processing. Inputs are the resources, data, that are put into a system to be processed. Any system, in order to operate and function, needs inputs. Inputs should have the following characteristics: i. Accuracy: The data to be input should be accurate as erroneous data will result in wrong output, i.e., GIGO (Garbage In Garbage Out). ii. Timeliness: The data should be provided to the system at the required time, as only timely data input will only give the desired output. iii. Relevance: The data should be relevant as irrelevant data would not provide the desired information. iv. Cost Effectiveness: The input data procurement should be cost effective and at the lowest possible price. v. Quantity: The quantity of the input data has to be sufficient so as to solve the purpose of the system. 18 2. Processor Processor is that part of the system which processes or manipulates the input data into output. The processor is the element of a system that involves the actual transformation of input into output. It is the operational component of a system. Processors may modify the input either totally or partially, depending on the output specification. 3. Output Output is the element for which the entire system is built; Output is what the user desires it is the end result. The output may be a product, a service or information. The most valuable thing for the user is output. The main aim of a system is to produce an output which is useful for its user. Output is the outcome of processing. 19 4. Control The control element guides the system. It is the decision–making subsystem that controls the pattern of activities governing input, processing, and output. The behavior of a computer System is controlled by the Operating System and software. For any system to operate efficiently and effectively, control is required in a system to control all inputs, processing and outputs and other activities. 5. Feedback When the output is obtained, it is compared with the expectation of the desired result, and the information which is received is called feedback. Feedback is essential for the betterment of the system and for the accuracy of the output. The actual result is compared with the standard result and the information received is termed as feedback. Feedback may be positive or negative. Positive feedback means the system is functioning right and negative feedback initiates action for improving the system. 20 6. Environment The system has to operate within an environment, all the components which affect the performance of the system constitute the environment of the system. All the external compounds that effect the system and guide how a system should function are referred to as environment of the system. The system should to able to customize as per the changing environment. 7. Boundaries/Interface ✓ Every system has certain limitations and it has to work under those limitations or defined boundaries. The limitations of the system help the interfacing of the system with another system, if there is a requirement of integration of two or more systems. ✓ A system should be defined by its boundaries. Boundaries are the limits that identify its components, processes, and interrelationship when it interfaces with another system. 21  Types of Systems The systems can be divided (classified) into the following types: 1) Open and closed systems 2) Physical and abstract systems 3) Deterministic & probabilistic systems 4) Man-made information systems. 22  Open and Closed Systems ✓ Open systems: Systems that interact with their ✓ Closed systems, on the other hand, do not environment. Practically most of the systems interact with the external environment. A are open systems. closed system does not interact with its ✓ An open system has many interfaces with its environment. It is isolated from environment and t can also adapt to changing environmental influences. A completely environmental conditions. It can receive inputs closed system is rare in reality. Examples: from, and delivers output to the outside of Thermos flask, pressure cookers, sealed system. An information system, organization, battery or laboratory experiment. company, biological are all examples of this categories. ✓ The main characteristics of closed systems ✓ The main characteristics of open systems are as are as follows: follows: i. Usually, they only exist as a concept. i. They take or give inputs or outputs to the ii. They are very rare and not operatable. external environment. ii. They can change as per the change in iii. They have a very short survival time. environment. iv. They do not take/give input/output from 23 iii. They can function effectively. the external environment.  Physical and Abstract Systems ✓ Physical systems are tangible entities. Physical ✓ Abstract systems are non-physical Systems are the systems which you can entities or conceptual that may be physically see and touch. You can see its formulas, representation or model of a components, parts, etc., which can also be real system. touched. ✓ These are usually theories, principles, ✓ Physical System may be static or dynamic in instructions, procedures, and concepts. nature. For example, keyboard and mouse are the physical parts of computer system which ✓ Such Examples are algorithms, are static. programming language, models include; DFD, ERD etc.. ✓ While, a programmed computer is a dynamic system in which programs, data, and applications can change according to the user's needs. 24  Deterministic and Probabilistic Systems ✓ Deterministic System The systems ✓ Probabilistic Systems: The systems that have whose outcomes are certain and are uncertain outcomes not based on predetermined sets of rules are called probabilistic systems. based on a predetermined set of rules are called deterministic systems. ✓ Examples are Weather forecasting, stock market, lottery games, mail delivery and many more. ✓ Examples are simple mathematic equations, algorithms, digital circuits, ✓ The main characteristics of probabilistic systems are as follows: traffic lights and many more. i. Their outputs are unpredictable. ✓ The main characteristics of ii. Their interrelationship with other systems is deterministic systems are as follows: uncertain. i. Their outputs are predictable iii. They can only provide probable estimates. ii. Their behaviour is totally known iv. These systems are controlled by chance events. iii. Known outputs for known inputs. 25  Man-Made Information System Man-made information system is an interconnected set of information resources to manage data for particular organization under Direct Management Control (DMC). This system includes hardware, software, communication, data, and application for producing information according to the need of an organization. The main purpose of information systems is to manage data for a particular organization. Maintaining files, producing information and reports are few functions. An information system produces customized information depending upon the needs of the organization. 26  Computer Based Information Systems This class of systems depends on the use of computer for managing business applications. For example, automatic library system, railways & Airline reservation system, banking system, etc. Computer-based information systems are of too many types. They are classified as: 1. Transaction Processing Systems (TPS) 2. Management Information Systems (MIS) 3. Decision Support System (DSS) 4. Office Automation Systems (OAS) 27  1. Transaction Processing Systems (TPS) ✓ A transaction processing system can be defined as a computer-based system that captures, classifies, stores, maintains, updates and retrieves transaction data for record keeping and for input to other types of CBIS. Transaction Processing Systems are aimed at improving the routine business activities on which all organizations depend. ✓ A transaction is any event or activity that affects the whole organization. Placing orders, billing customers, hiring of employees and depending cheques are some of the common transactions. The types of transaction that occur vary from organization to organization. ✓ The primary objective of TPS is to increase the speed, accuracy and efficiency of transaction processing in a business activity. The most common example is banking which involves transactions such as deposits, withdrawals and interests on balances. 28  2. Management Information System (MIS) As the name suggests, Management Information System (MIS) are for the management to analyse the information and take decisions. In MIS, data is taken as an input from transaction processing systems or other information systems and is processed (converted) into meaningful information. A good MIS system is designed keeping in mind the information that a manager needs for decision making and how the manager uses that information for his/her job. The data is collected from various subject areas for development of a comprehensive and accurate model for an efficient MIS system. Many organizational tasks are supported by the MIS system including decision making and decision analysis and MIS systems also help compile the information from various information functions and the output can be used for effective decision making. An important element of MIS is database. 29  3. Decision Support Systems (DSS) DSS is a computer-based system that helps users make informed decisions, particularly when dealing with complex, semi-structured or unstructured problems. DSS is designed to assist with decision- making by providing necessary tools, data, and models that help analyze different scenarios and predict outcomes. However, a decision is considered unstructured if there are no clear procedures for making the decision and if not all the factors to be considered in the decision can be readily identified in advance. Judgement of the manager plays a vital role in decision-making where the problem is not structured. For example, in hospitals, a clinical DSS helps doctors make informed medical decisions. The system analyzes patient data (e.g., symptoms, medical history, lab results) and provides recommendations for diagnosis or treatment plans. For example, diagnoses based on a patients symptoms or flag potential drug interaction. 30  4. Office Automation System (OAS) OAS are systems which help in automating the daily office activities. The most common functions which are covered under this aspect are word processing, spreadsheets, communication through e-mail, voicemail, teleconferencing, videoconferencing, desktop publishing, e-scheduling, record arrangements, etc. Today’s offices cannot be imagined without office automation systems. The basic activities of an OAS are: (1) Data entry and storage (2) Data processing (3) Data exchange (4) Data management. 31  Summary of computer-based information system (CBIS) In summary, the figure 1.1 shows the organization chart of computer-based information system (CBIS). The figure 1.2 shows the hierarchical view of CBIS. Figure 1.1: Organization Chart of CBIS Figure 1.2: Hierarchical View of CBIS 32  Summary of the Lecture In this section, we have learned: 1)What is SAD? 2)Concepts of systems and its Types. 3)Characteristics of a System. 4)Elements of a system. 5)MMIS 6)CBIS and Its Classifications. 33 Thank You! 34  Teams code for this course Section-1: 2e7cj2g Section-2: carndws 35