Information System Analysis Introduction General System Theory The basics of the general systems theory and the information systems are: General System Theory Importance for information systems 1 Components of a system Delineate components interact interrelation during analysis and their 2 A system is a whole Be sure to define the entire before examining subsystems 3 Systems are goal-seeking What is the goal of an information system 4 Systems have inputs and A major design task is to specify inputs & outputs outputs system General System Theory General System Theory Importance for information systems 5 Systems transform inputs A major design task is to specify to yield output processing to produce outputs from inputs 6 Systems must be controlled Information systems help to control organization, Information systems have to have feedback on their own performance & be controlled 7 Systems forms a hierarchy Information systems design is hierarchical task, systems consist hierarchies of subsystems 8 Systems exhibit differentiation Information systems have many specialized parts 9 Systems exhibit equifinality There are ways to design a system to achieve desired goals a of System Definition A system is an organized collection of people, machines, procedures, documents, data, or any other entities such that they interact with each other as well as with the environment to reach a predefined goal. System Definition A system is a collection components (subsystems) together to achieve some biological system, computer system) of interrelated that function outcome (e.g. system, social System Definition A subsystem is a system which is an element of a larger system. The large system is called "Super System". System Definition Data are groups of characters recognized as having the lowest level meaning: they are raw facts & opinions. System Definition Information is data, which has been processed to become meaningful to the users, and upper management. Information has more meaning than data in that is useful in a present decision situation. System Definition A message is a group of characters that is stored, processed and transmitted in the information system of an organization. In other words: information in an organization is stored, processed, and transmitted as messages. System Definition Knowledge has the highest level of meaning because it represents information that can be potentially useful in future decision situation. System Definition Information System The information system of an organization may be defined as a system that serves to provide information within the organization when & where it is needed in any managerial level. System Definition Information system is a collection of interrelated components that collect, process, store and provide as output the information needed to complete business tasks (e.g. payroll system) System Definition System Analysis: the process of understanding and specifying in detail what the information system should do. System Analyst: A professional who used analysis and design techniques to solve business problems (involving information technology) Characteristics of Systems: A system must have: Purpose: systems do not just appear out of nowhere, they exit for a purpose. Example: an airline system transports passengers Characteristics of Systems: Structure: a system must be organized in a way that gives it structure. The components of the system must work together in some preplanned way, so the system can operate in an orderly manner. Characteristics of Systems: Example: A department store's financial system is structured to reflect the interaction of the pricing, purchasing, inventory, and billing activities. Characteristics of Systems: Interdependence: In order for a system to function, it must receive input from other systems. The system processes the input to produce output, which is used as required input for still another system. In other words, a system interacts with the environment in which it operates. Characteristics of Systems: Example: a purchasing department might receive requests for material form the factory and then generate purchase orders to be routed to vendors. Characteristics of Systems: Functional decomposition: dividing a system into components based on subsystems (which are in turn further divided into subsystems) Characteristics of Systems: Example: A hospital may have separate subsystems for the pharmacy, the laboratory, and the patient medical records. In addition, each of these subsystems may have subsystems of its own. Elements of systems: System boundary: the separation between a system and its environment (where inputs and outputs cross) Elements of systems: System Environment: It is the source of the system inputs and destination for the system outputs ( any thing outside the system’s boundary) Elements of systems: System Inputs: are the physical objects and data that cross the system’s boundary to communicate with it. System Outputs: are the physical objects and Information that produced by the system. Elements of systems: Processing: is the conversion of inputs to outputs. Data processing activities include sorting, searching, merging, summarizing, calculating, and similar operations General Depiction of a System input boundary interrelationship subsystem output Types of Information Systems 1. Transaction processing systems (TPS): TPS are computerized information systems that were developed to process large amounts of data for routine business transactions such as payroll. Types of Information Systems TPS are information system applications that capture and record information about the transactions that affect the organization (e.g. the sale of an item, a withdrawal from an ATM etc.) Types of Information Systems TPS eliminates the tedium of necessary operational transactions. TPS Reduces the time once required to perform them manually. Types of Information Systems Note: TPS are boundary-spanning systems that permit the organization to interact with external environment. Types of Information Systems 2. Management Information Systems (MIS) MIS may be defined as "a system that collects and processes data (information) and provides it to managers at all levels who use it for decision making, planning, program implementation, and control". An information system is comprised of all the components that collect, manipulate, and disseminate data or information. Types of Information Systems It usually includes hardware, software, people, communications systems such as telephone lines, and the data itself. The activities involved include inputting data, processing of data into information, storage of data and information, and the production of outputs such as management reports. Types of Information Systems MIS do not replace TPS; rather, all MIS include transaction processing. So, it takes information captured by the TPS and produce reports management needs for business. planning and controlling Types of Information Systems MIS support a broader spectrum of organizational tasks than TPS, including decision analysis and decision making. Types of Information Systems Finally: MIS focus on information not on data MIS are designed from an organizational perspective rather than from a business transactions perspective. Its users are primarily the middle & upper management. Types of Information Systems It is oriented to management control Standardized report & interrogative reports are major outputs of an MIS. It deals with well structured tasks Types of Information Systems 3. Decision Support Systems (DSS) A higher-level class of computerized information systems. The DSS is similar to the traditional MIS, because they both depend on a database as a source of data. DSS departs from the traditional MIS because it emphasize the support of decision making in all its phases. Types of Information Systems Finally: DSS focus on knowledge & on decision It’s user initiated & controlled It is oriented to the individual manager It supports strategic planning The major output (s) of DSS is interactive/iterative reports It deals with semi-structured & unstructured problems Types of Information Systems 4. Expert Systems & Artificial Intelligence An expert system is a programmed decision-making information system that captures and reproduces the knowledge of an expert problem solver or decision maker and then simulates the “thinking” or “actions” of that expert. Types of Information Systems Expert systems are implemented with artificial intelligence technology that captures, stores, and provides access to the reasoning of the experts. The System Development Life Cycle (SDLC) System Development Life Cycle (SDLC) is the overall process of developing information systems through a multistep process from investigation of initial requirements through analysis, design, implementation and maintenance. The System Development Life Cycle (SDLC) The major phases of SDLC: Preliminary Investigation and feasibility Study Planning Phase Analysis Phase Design Phase Implementation and Operation Evaluation and Maintenances Preliminary Investigation and feasibility Study This phase identifies clearly the nature and scope of the problem. The preliminary consists of: investigation phase Preliminary Investigation and feasibility Study 1. A Problem Statement/Objective Identify where you are now and where you want to get by performing this project. Ask many different questions to a variety of people in order to get a good idea of what they have in mind. Preliminary Investigation and feasibility Study 2. A Feasibility Study You look at whether to move on to the analysis phase or not. Here we have three aspects:- Preliminary Investigation and feasibility Study A. Technically feasible : With the technology we have, can we get the project done? Can we obtain equipment and personal to develop, install and operate the system? Preliminary Investigation and feasibility Study B. Economically feasible : Determine whether the time and money are available to develop the system It includes the estimated cost to purchase Hardware & Software. Preliminary Investigation and feasibility Study C. Operational Feasibility Determine if the human resources are available to operate the system once it has been installed. Users that do not want a new system may prevent it from becoming operationally feasible. Preliminary Investigation and feasibility Study 3. Preliminary Investigation Report Prepare this report for management and it should specify the identified problems and what further action is recommended. Planning phase Here, the engineer gathers information about the problem and the requirements. He/she then sets criteria and constraints for a solution and generates a number of alternative solutions. Analysis Phase The analyst studies the organization’s current procedures and the information systems used to perform tasks such as payroll. Analysis has several sub phases:- Analysis Phase 1. 2. 3. Determining the requirements of the system (it should be careful study) Study these requirements and structure them according to their interrelationships and eliminating any redundancies. Generate alternative initial designs to match the requirements. Analysis Phase The output of the analysis phase is a description of the alternative solution recommended by the analysis team. Design Phase It defined as the creation of a new system in accordance with a preconceived plan from the analysis phase. Design Phase – – – – – – Activities:Design and integrate the network Design the user interfaces Design the system interfaces Design and integrate the database Prototype for design details Design and integrate the system controls Implementation & Operation 1. 2. 3. 4. Implementation includes:Coding Testing Installation Initial user support such as training programs Implementation & Operation During the operation the programmers make the changes that users ask for and modify the system to reflect changing business conditions Note:The documentation and training program are finalized during implementation, documentation is produced throughout the life cycle.