Systems Analysis and Design PDF

Systems Analysis and Design What is a System? > Set of related components that produce specific results. Ex. Society, Computer System. 7 Parts of a System: o Components: irreducible part or an aggregate parts o Interrelationships: the function of one is somehow tied to...

Systems Analysis and Design What is a System? > Set of related components that produce specific results. Ex. Society, Computer System. 7 Parts of a System: o Components: irreducible part or an aggregate parts o Interrelationships: the function of one is somehow tied to the functions of the others. o Boundary: within which all of its components are contained and which establishes the limits of a system, separating it from other systems. o Environment: everything outside the system’s boundary that influences the system. o Interfaces: the points where the system meets the environment. o Input o Output DIKP Pyramid Data Manipulation Data -> Meaningful Analysis & Manipulation > Infomation Information: for an information to be used in management, it needs to satisfy the following: Accurate : error-free Verifiable: can be confirmed as true Complete Filtering Information overload Relevant Timely: delivered on time Information Systems An integrated set of components for collecting, storing, managing, and processing data and for providing information, knowledge, and digital products Used to run interorganizational supply chains and electronic markets. A complex concept that provides decision makers with the information needed for decision-making Can be found in every organization, big or small. Components of Information Systems 1. Computer Hardware:the hardware in an information is the technology you can touch — the physical aspects of technology. Computers, tablets, mobile phones, disk drives, and more are all examples of information system hardware. Hardware is often considered the most visible aspect of an information system. Hardware is important to the effectiveness of an information system because most of the software and data are accessed via hardware. Likewise, people use the hardware and many processes are carried out on the technologies established as a party of the information system. 2. Computer Software: software builds directly upon the hardware of an information system. In fact, the software is a set of instructions that tells the hardware what to do. Unlike hardware, software is not tangible. You can’t touch it. When software is being programmed, instructions are written to tell the hardware what to do. There are several types of software within two main categories of operating-system software and application software. 3. Data: the third component of an information system. You can think of data as a collection of facts and information. For example, your street address and other info are all pieces of data that helps describe you. Like software, data is not tangible. By itself, data is not particularly useful. However, aggregated, indexed, and organized data is a powerful tool for organization. Organizations collect all sorts o f data and use this data to make informed decisions. These decisions can then be analyzed based on their effectiveness. This additional analysis and data dissection help improve the organization. 4. People: when considering information systems, focusing on the technology components — hardware, software, and data – is easy. However, we must look beyond these tools to fully understand how they can integrate into an organization. The next step is to focus on the people involved in the information system. When considering the human aspect of an information system, it’s important to look at the big picture. 5. Processes: the last component of an IS. A process is a series of steps undertaken to achieve a desired outcome or goal. IS are becoming increasingly integrated with organizations’ processes. This integration brings more productivity and better control to those processes. However, simply automating activities using technology is not enough. Decision-Making One of the key functions of management is decision-making. Levels of Management: Strategic Planning o A high-level overview of the organization o Long term plan (typically 5 years) o Forward looking Tactical Planning o Tactics used to achieve the strategy o Short term plan (typically 1 year or less) o Includes specific goals, budget, resources Operational Planning o Plan for day-to-day running or the organization o Controlled via daily/weekly/ monthly reports. Types of Decisions Programmed Decisions: bare made on structure problems. o Note: Structured Problems: well-defined issues that can be solved using established rules, processes, or algorithms Non-programmed Decisions: comes from ill-defined problems. o These problems often come from crises, or events that have not occured in the past. Partially Programmed Decisions: this type of decision is a result of having both structured and unstructured components at the same time. Partially structured problem Decision-Making Process 1. Set the objective/s. 2. Identify constraints.  3. Identify alternatives. 4. Gather appropriate data and information. 5. Evaluate alternatives. 6. Choose the most acceptable alternative. Systems Planning and Development Systems Development Life Cycle Is a conceptual model used in project management that describes the stages involved in an information system development project from an initial feasibility study all the way through maintenance of the completed application. Is a series of phases or stages of an information system. It encompasses the entire process from the initial planning and system concept to system implementation, maintenance, and eventual retirement. Development Stage The Systems Development Life Cycle consists of 5 phases: Phase 1: Preliminary Investigation - determine the problem Phase 2: Analysis - understand the existing system Phase 3: Design - plan for a new system Phase 4: Development - create the new system Phase 5: Implementation - convert to the new system Phase 1: Preliminary Investigation A.k.a. feasibility study, systems survey Initial investigation and brief study of the problem. The systems analyst should determine what the problem is and what to do with it. Goal: come up with a rough plan of how to proceed with the project. Has two (2) stages: -Definition of the problem -Feasibility study Phase 2: Systems Analysis: the purpose is to understand the existing system. 1. Data collection There are no standard procedures for gathering data because each system is unique. o Some sources: 1. Written documents 2. Interviews Structured Unstructured 3. Questionnaires 4. Observations 2. Data analysis Data flow diagram o sort of road map that graphically shows the flow of data through a system. o Useful tool for depicting procedures and data flow. 3.Systems requirements The systems analyst must prepare a list for a proposed or new system requirements. "The paper and pen cannot forget, but the mind can." 4. Report to management Recommendations and suggestions can be discussed. Phase 3: Systems Design: a phase when the new system is thoroughly planned. Design Aspect Data Design o involves transforming the data model specified during the analysis phase into representations ready for implementation. o How the data of the application will logically look like when implemented, thus, using data structures Architectural Design: Shows the interaction of the different components of the system. Procedural Design: defines the algorithms for each of the functions that need to be provided by the system. o Algorithms - procedure used for solving a problem or performing a computation. Interface Design: lay-out of the interface and the various interactions of the user with the system. Phase 4: Systems Development: the project team develops the new system based on the requirements and design that were finalized in the earlier stages. Developers write code using the appropriate programming environment and language. The team obtains and installs new components and programs. Phase 5: Systems Implementation: in this phase, the system has been developed and is ready for integration and use. It has three (3) stages: 1. Training 2. System Conversion: this is the time when the old system is finally discarded, and the new system is put into effect. 3. Evaluation Stage 1: Training: delivered not only during the implementation of the system, but also when there are new users of the organization. The training must impart the following: Purpose and objectives of the system Differences between the old and the new Overview of the functionalities and procedures Use of user manual and help screens Duties and responsibilities of end users and support personnel Demo of the system Stage 2: Conversion - this is the time when the old system is finally discarded, and the new system is put into effect. Types of conversions: > Parallel The old and the new systems are operated simultaneously while comparing their performances and outputs. When the new system gets the confidence of the management and end users, the old system is then terminated > Direct The old system is terminated all together, and on the next day, the new system is implemented. > Phased Conversion Gradual phase out of the old system while the new system gradually phases in. > Pilot Conversion The new system is implemented in a selected unit of the organization. This may be done as a parallel, direct, or phased conversion. Stage 3: Evaluation: Post-Implementation Audit and Maintenance The new system is subject to an audit by a third-party organization. Parameters to be evaluated: o Adherence to design o Performance against the old system o Operating cost Management of Systems Development Project What is a project? A temporary sequence of unique, complex, and connected activities having one goal or purpose and that must be completed by a specific time, within budget, and according to specification. Why do projects fail? Unclear objectives Scope creep Unrealistic expectations Limited resources Poor communication Scheduling delays Project Manager Not necessarily a senior manager. Can be anyone in-charge. Basic functions include planning, staffing, organizing, scheduling, directing, controlling, and closing. System Development Team (SDT) Systems Analysts: studies the problems and needs of an organization to determine how people, data, processes, and information technology can best improve and advance businesses. Systems Designer: translates the system users’ business requirements and constraints into technical solutions. Programmers: whose responsibilities include that of both the computer programmer and the systems analyst. End Users: people who use or are affected by the information system on a regular basis. o Internal users o External users o Remote and mobile users Project Leader Chosen among the team. He/she ensures that the tasks are accomplished on or before a pre-set. PROJECT MANAGEMENT TOOLS 1. PERT/CPM (Project Evaluation and Review Technique/Critical Path Method) Developed in the late 1950s to plan and control large weapons development projects of the U.S. Navy. Graphical model that depicts project tasks and relationships between those tasks. 2. Gantt Chart Created by Henry L. Gantt in 1917 Most used in project scheduling and progress evaluation tools. A simple horizontal bar chart that depicts project tasks against a calendar. 3. Constructive Cost Model (COCOMO) is a software cost estimation model that helps predict the effort, cost, and schedule required for a software development project Developed by Barry Boehm in 1981. projects are categorized into three types: Organic Semi-detached Embedded According to Boehm, software cost estimation should be done through three stages: - Basic Model - Intermediate Model - Detailed Model Basic Model Effort = a(KLOC)^b Person-Month Tdev = c(Effort)^d Months KLOC = Kilo Lines of Code a, b, c, d = constants for each group of software products Tdev = estimated time to develop the software, expressed in months Effort = total effort required to develop the software product, expressed in person-months (PMs) How will COCOMO help in decision-making? - Identify the time needed - Identify cost based on LOCs - Understand the required manpower based on data - Know the needed number of persons for the project - What formula? Organization Information Systems and Systems Life Cycle Management Levels in Organization Strategic Level Tactical Level Operational Level Organization Information Systems 1. Transaction Processing Systems The type of system where the reception and processing of data about the business. Also known as data processing systems. Provide management-oriented reports. an information system used for decision-making, and for coordination, control, analysis. and visualization of information in an organization (Bourgeois. 2014). 2. Management Information Systems Provide management-oriented reports.  An information system used for decision-making, and for the coordination, control, analysis, and visualization of information in an organization. 3. Decision Support Systems Provides decision-oriented information. Has more advanced filtering and manipulating features than MIS Note: calculate and predict for decision using the gathered data 4. Executive Information Systems Used by organization’s top-level management. A specialized Decision Support System (DSS) Access data and information concerning the critical success of the organization Decision Support Systems vs Executive Information Systems ang pinagkaiba lang ng DSS sa EIS ay kung anong level of management ang siniserve nitong IS. More manipulation tools ang EIS compare kay DSS. ang EIS mas simplified ang itsura kasi siniserve niya ang highest level of management. SYSTEMS LIFE CYCLE Stage 1: CONCEPTION Starts when someone has a lightbulb moment or idea on how much the system can help provide better information. Stage 2: DEVELOPMENT Members of the project team, a.ka.a. Systems development teams gather and work towards the realization of the idea. Members o Systems analysts o Systems designers o Programmers o End users Brainstorming and development of the system software Stage 3: BIRTH -This is the stage where the developed system has been completed. -Modifications, and pilot-testing are done. Stage 4: PRODUCTION Stage when the information system is finally implemented to the organization. Can be the longest stage among the system. Stage 5: DEATH When maintaining the system becomes too expensive, and disadvantages dominate its advantages. ASSESSING FEASIBILITY How do you know if a system is worth it before you actually invest in it? The SDT must prepare a proposal detailing the technical and non-technical aspects of the proposal system. This way, the institution or organization can weigh in whether the system is worth investing in. Technical Feasibility - refers to the capacity of the organization to develop, implement, and handle project, Economic Feasibility - benefits outweigh the cost. o Benefits o Costs  IN-HOUSE VS. PROPRIETARY In-house: IT services are a variety of services provided by an organization’s internal IT team. These services can range from basic technical support and help desk services to more complex tasks such as systems analysis, project management, database, administration, and software development. Advantages: Disadvantages: > Full control over team Costly > Better communication Manpower and time-consuming > Better understanding of the company’s values Proprietary: it is a closed system that is designed and implemented by a single vendor, and is not compatible with other technology providers. only the object code is published; the source code is held secret in order to control customers and markets. Advantages: Disadvantages: Increased efficiency Potential communication problems Facilitated sealing Transparency and security issues Reduced costs Less control Application Development Tools Aid programmers and non-programmers in the development of application software. - Personal Computer Tools Any tools/programs/application software that can process data. Tools that run on PCs. E.g. microsoft excel, microsoft access - Query Languages Used to retrieve data from a database or similar tools. Query: refers to instructions or sequence of instructions for the computer to execute to retrieve data. (The formulas used to retrieve data) - Graphics Generators Construct graphs from specified data. Provides visual representation of data using various types of graphs. - Application Generators Computer languages can be procedural or non-procedural. Procedural is a computer language that requires programmers to specify how an operation such as data retrieval is to be carried out. Non-procedural is a computer language that only requires the programmer to identify what data is to be processed. The software takes care of the operations. Application generators are non-procedural languages. A.k.a. Code generators. Custom codes, however, cannot be generated but written by programmers. Consists of the following module: o Database management system o Report generator o Database query language o Graphies package o Special purpose software E.g. NOMAD. FOCUS, RAMIS - Computer-Aided Software Engineering Tools (CASE) Software developers created a handy tool kit used for systems analysis, design, and programming. This tool kit includes: Design tools o CASE Design Tools allows diagrams to be easily drawn, redrawn, and modified. With just one click, diagrams can be created quickly. Prototyping tools: used to create a prototype (model/simulation) of a system. Information Repository tools: handles data dictionary (metadata and database schemas) Program development tools o Program Structure Charts Generators: creates hierarchical graphs showing the programs comprising the information systems and their relationships. o Code Generators: generates the skeletal code. o Program Preprocessors: subjects a program to security by simulating the program’s execution. o Test Data Generators: used in program testing Methodology tools: presents the status of the project that is accessible to the members of the SDT. Office Automation Office Automation: Hardware, software, and processes for automating office tasks. Cloud Computing: Online storage and data-sharing system. Automation Benefits: Faster workflows, less manual work, and cost efficiency. Benefits of Office Automation: Saves time by reducing repetitive tasks. Enhances accuracy and reduces human error. Improves communication and collaboration. Enables easy data tracking and reporting. Reduces paper usage, promoting eco-friendliness.