System Integration & Architecture PDF

Temporary System Integration & Architecture Require resources, often from various areas Reviewer (Midterms) Should have a primary sponsor Papasa yanll...

Temporary System Integration & Architecture Require resources, often from various areas Reviewer (Midterms) Should have a primary sponsor Papasa yanll Inovolve uncertainty System Integration-process,approaches,drivers, tools and techniques required for successful system integration System- An array of componets desgined to accomplish a particular objective according to plan System Thinking - is a way of understanding of entity in terms of its purpose. 3 major steps followed in system thinking 1.Identify a containing whole (System), of which the thing to be explained is a part 2.Explain the behavior or properties of the containing the whole 3.Explain the behavior or the properties of the thing to be explained in terms of its role/s or function/s within its containing whole (Ackoff,1981) System Integration-is the combination of inter- related elements to achieve a common objective/s System Architecture-it defines its high-level structure, exposing its gross organization as collection of interacting components Elements needed to model a software architecture include: Components Connectors System Properties Styles Project-is a temporary endeavour undertaken to accomplish a unique product or service Attributes of project Unique purpose  We can analyze a formal organization using the Where do Information Systems following 4 Project Originate? Problems?-problems are undesirable (four)frames; situation that prevent the business from 1.Structural Frame-Focuses on roles and fully achieving its goals(User discovering a responsibilities, coordination and control. problem) Opportunity-Is a chance to improve 2.Human Resources Frame-Focuses on providing business even in the absence of specific harmony between needs of the organization and problem needs of the people. 3.Politcal Frame-Assumes Organizations are Directive-New requirement that imposed by management, government, or some coaliation composed of varied individuals and external influence. interest groups. Conflict and power are key issues. Stakeholders-are the people involved in or affected by project activities. Stakeholders include: Project sponsor and project team Support staff Customers Users Suppliers Opponents to the project What helps projects succeed? According to Sandish group's report “CHAOS 2001: A recipe for a success" the following items help it project to succed, in order of importance: Executive Support User involvement Experienced Project Manager Clear Business objectives Minimized Scope Standard Software infrastructure Firm basic requirements Formal methodology Reliable estimates Understanding Organizations  4.Symbolic Frame-Focuses on symbols and meaning related to events.Culture is important. functional,divisional,matrix and project-based. completing projects. A good organizational structure will allow people and Many Organizations Focus on the groups to work effectively together while developing Structural Frame hard work ethics and attitudes. Most people understand what organizational charts are Many new managers try to change organizational structure when other changes are needed 3 Basic Organizational Structure Functional -In a functional organizational structure, the organization is divided into departments based on specialized functions (e.g., marketing, finance, human resources,operations). Project-In a project organizational structure, the organization is arranged around projects rather than functional departments. Each project has a dedicated team that works towards specific goals. Matrix- A matrix organizational structure combines elements of both functional and project structures, creating a dual-reporting system. Employees report to both functional managers and project managers. Basic Organizational Structures Organizational structure depends on the company and/or the project. The structure helps define the roles and responsibilities of the members of the department, work group,or organization. It is generally a system of tasks and reporting policies in place to give members of the group a direction when Functional Structure-People who do similar task, have similar skills and/or Project Organization Structure-the teams are put jobs in an organization are group into together based on the numbers of members needed functional square.The advantages of to produce or complete the project. this kind of structure include quick decision making because the group members are able to communicate Project Phases and the Project Life Cycle easily wwith each other.People in functional structures can learn from each other easier because they already A project life cycle is a collection of project phases possess similar skill sets and interests. Divisional Structure-the company will coordinate inter-group relationships to Project phases vary by project indusry, but some create a work team that can readily meet general phases include: the needs of a certain customer or group of customers. Concept Development Matrix Structure-are more complex in that they group people in two different Implementation ways:by the function they perform and by Support the products team they are working with. In a matrix structure the team members are given more autonomy and expected Product Life Cycles to take more responsibility for their work. This increases the productivity of the The System Development Life Cycle ( SDLC) - is a team, fosters greater innovation and framework for describing the phases involved in creativity, and allows managers to developing and maintaining information systems. cooperatively solve decision-making problems through group interaction. The four general types of organizational  System developments can follow A project should successfully pass through each of the project phases in order to continue on to the next ·Predictive Models-the scope of project can be clearly articulated and the schedule and cost Management reviews (also called phase exits or kill points) can be predicted. should occur after each phase to evaluate the project's progress, Adaptive Models-Projects are mission driven likely success, and component based, using time-based cycles to meet target dates. Predictive Life Cycle Models Waterfall Model-has well defined,linear stages of a systems development and support. Spiral Model-shows that software is developed using an iterative or spiral approach rather than a linear approach. Incremental-release model provides for progressive development of optional software Prototyping Model-To clarify user requirements RAD Model-is used to produced system quickly without sacrificing quality. Adaptive Life Cycle Models Extreme Programming (XP)-Developers program in pair and must write the test for their own code.XP teams include developers,managers, and users. Scrum-Repetitions of iterative development are referred to as sprints, which normally last thirty days. Team often meet everyday fora short meeting, called a scrum. Distinguishing Project Life Cycles and Product Life Cycles The project life cycle applies to all projects,regardless of the products being produced Product life cycle models vary considerably based on the nature of the product Most large IT systems are developed as a series of projects Project management is done in all of the product life cycle phases Why Have Project Phases and Management Reviews?  Modeling tools and methodologies using and continued compatibility with Unified Modeling Language (UML) organizational goals. Testing System Development Life Cycle (Kendall& Kendall Terminology) Characteristic of good Req's Figure 1.2 The Seven Phases of the Systems 1. Describes What, Not How. Development Life Cycle 2. Atomic. i.e., it should have a single purpose 3.Unique. 1.Identifying problems 4.Documented and Accessible. opportunities and objectives 5.Identifies Its Owner. 2.Determining information requirements 6. Approved. After a requirement has been 3. Analyzing system needs revised,reviewed,and rewritten, it must be approved by its owner. 4. Designing the recommended system 5.Developing and documenting software 7. Traceable. A good requirement is traceable; it should be possible 6.Testing and maintaining the system to trace each requirement back to its source. 7.Implementing and evaluating the system 8.Necessary. Requirements-a system cannot be analyzed,desgined, and evaluated unless the problem is understood and requiremnets elicited.Requirments are the fundamental basis of all system development process. System architects will always base of the requirements elicited by the system analyst to design an architectural view of the system.Besides much as the system is designed and there is need for integration say business process integration,legacy integration,new systems integration,business-to-business integration, integration of commercial- off-the-shelf (COTS) products, interface control and management,testing, integrated program management,integrated Business Continuity Planning (BCP), requirement is the basis. Sub Topics Requirements elicitation,documentation and maintenance  9.Complete. When is it done? 10.Unambiguous How is it done? 11.Quantitative and testable Why is it done? 12.Identifies applicable states 14.States Assumptions. All assumptions should be stated. System Requirements 15. Use of Shall, Should, and Will.A mandatory Outputs requirement should be expressed using the word shall Input (e.g., "The system shall conform to all state laws Processes 16.Avoids Certain Words. The words optimize,maximize,and Timing minimize should not be used in stating Control requirements,because we could never prove Volume,Sizes,and Frequencies that we had achieved them. Requirements Life Cycle Elicitation Phase-Starting point of the requirement process. Organization Phase-There is no transition of the requirements, but simple clarification and categorization. Analysis Phase-This represent transformation Prototype Phase-In this way poorly understood requirements may be tested perhaps, strengthened, corrected, or refined. Requirement Documentation and specification-This represent the requirements as the finish product of stakeholder requirements team. Requirement Elicitation-Requirements determination addresses the gathering and documenting of the true and real requirements for the information system being developed. Requirements is the wants and/or needs of the user within a problem domain Requirements Determination Questions: Who does it? What is done? Where is it done?  The timing and the synchronization of the Data/Information collected can be about; above people,organization,work and work environment. Non-Functional Requirements-are global Fact-Finding Methods constraints on a computer system (ex. Sampling (of existing documentation,forms Development cost, operational cost, and databases) Research and site visits(Participation) performance,reliablity) Observation of the work environment The Challenge of Non-Functional Requirements: Questionnaires Hard to model Intervies Usually stated informally,so are: Prototyping Often contradictory, JAD/Join Requirements planning(JRP) Difficult to enforce during development Types of Requirements Difficult to evaluate for the customer prior delivery User Requirements-statements in natural language plus diagram of services the system provides, together with its operational constraints Functional Requirements-Describe what system should do Non-Functional requirements- consist of constraints that must be adhered during development(implementation and design) System Requirements What we agree to provide Describe system services Contract between client and contractor Functional Requirements What inputs the system should accept What outputs the system should produce What data the system should store that other system might use What computations the system should perform  Non-Functional Requirements Requirements Documentation Define system properties and constraints Maintainability, Enhanciability, e.g.reliability, response time and storage Portability,expected market or product lifespan requirements.Constraint are I/O device capability, system presentations. Process requirements may also be specified mandating Limits on development a particular programming language or development method E.g. development time limitations,resource Examples of NFR availability and methodological standards. Interface Requirements Economic Requirements How will the new system interface with its environment? User interfaces and “user-friendliness" Interfaces with other system Performance Requirements Time-response time Throughput-transactions per second Security Permissible information flow Who can do that Survivability Operating Requirements Physical constraints (size & weight) Personnel availability & skill level Accessibility for maintenance Environmental conditions Life Cycle Requirements e.g.restrictions on immediate and/or long-term costs. 2 types of documents realized from the requirements elicitation phase.These indude; User Requirements Specification Document System requirements specification documents User requirement specification-URS/URD The URS documents outlines precisely what the user (or customer) is expecting from the system User Requirement Specification may incorporate the functional requirements of the system or may be in a separate document labeled the Functional Requirements Specification-the FRS. The URD has the following information: 1. Functional Requirements 2. Non Functional Requirements Tools that aid in developing & understanding reqs Affinity Diagram Force Field Analysis Ishikawa Fishbone “cause and effects) diagram Pareto Diagram Pugh Chart Quality Function Deployment (QFD)  Affinity Diagram An affinity diagram is a visual tool used to organize and categorize ideas, insights, or information based on their natural relationships. It's particularly useful in brainstorming sessions, problem-solving,and project planning. Force Field Analysis Force Field Analysis is a decision-making tool developed by Kurt Lewin, used to identify and evaluate the forces that support or hinder a change or decision. It helps organizations understand the dynamics of change by analyzing both driving and restraining forces. Force Field Analysis Farca feld analysis is a toot that hepo you visuaize ard evaute the forces that aflect a skuaicn or a change. Ishikawa fishbone cause and effect diagram The Ishikawa Fishbone Diagram, also known as a cause-and-effect diagram or fishbone diagram, is a visual tool used to systematically identify and analyze the potential causes of a specific problem or effect. It helps teams explore the root causes of an issue and organize ideas for problem-solving. Fishbone Diagran