System Integration & Architecture Lecture Notes PDF

System Integration & Architecture * SYSTEM INTEGRATION & ARCHITECTURE 1  Introduction Many systems are built to easy, improve and transform organizations. Some organizations have many departments which run systems which are independent of each other. And systems built sometimes, ma...

System Integration & Architecture * SYSTEM INTEGRATION & ARCHITECTURE 1  Introduction Many systems are built to easy, improve and transform organizations. Some organizations have many departments which run systems which are independent of each other. And systems built sometimes, may not have an abstract view (architecture) which leads to failure of system interoperability. There is need to have architectural view of the system as a priority to help in the design to avoid the likeliness of system failure. * SYSTEM INTEGRATION & ARCHITECTURE 2  Introduction Besides after the system has been designed and developed in consideration of the size of the organization, i.e. most especially when the organization is large, need is required to integrate such systems to ensure flexibility, Speed, Cost , Standardization, Data integrity, reliability and robustness. This can help Information Technology (IT), energy, and financial services industry among others to have an easy to use integrated system. * SYSTEM INTEGRATION & ARCHITECTURE 3 What students need to know Systems Integration (SI) process, approaches, drivers, tools and techniques required for successful SI, critical success factors, and best practices. The course focuses on how a proposed system will be integrated with other existing or planned systems. It addresses the System Integration problem using architectures as the basis and then addresses the evaluation of the architectures in terms of the capabilities they provide. * SYSTEM INTEGRATION & ARCHITECTURE 4 What students need to learn * The theory and practice of business process integration, SYSTEM INTEGRATION & ARCHITECTURE 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). 5  Aims To provide the students an understanding of the technical and business process issues involved in systems integration. * SYSTEM INTEGRATION & ARCHITECTURE 6 Learning outcomes On completion of this course, the students will be able to: ◦Identify integration issues upfront in the process of System Integration and should be able to identify the best practices that ensure successful System Integration. ◦Have an understanding of the technical and business process issues involved in systems integration. * SYSTEM INTEGRATION & ARCHITECTURE 7 Teaching and learning pattern Teaching this course will be in lecture form. A number of case studies will also be used to illustrate some concepts as mentioned in the indicative content. * SYSTEM INTEGRATION & ARCHITECTURE 8  Indicative content The System of Systems Integration Problem ◦ Human, Organizational, Societal Cultural, Economic, and Technological aspects; ◦ Processes, approaches, drivers, tools and techniques required for successful SI, critical success factors, and best practices in Systems Integration; ◦ The Role of Architectures in Systems Integration; ◦ Integration in a System of Systems and a Federation 60 of Systems; ◦ Model Based Architecture, Design, and Integration; ◦ Systems of Systems Interoperability; ◦ Evaluation of architectures; ◦ Measures of Performance and Effectiveness; * SYSTEM INTEGRATION & ARCHITECTURE 9  Indicative content ◦ Assessment of System Capabilities; ◦ Analysis of Alternatives; ◦ Case studies and examples from the Information Technology (IT), energy, and financial services industry to illustrate the concepts discussed. The theory and practice of 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). Specific focus will be given to issues of interface integration and interoperability of systems. * SYSTEM INTEGRATION & ARCHITECTURE 10  Assessment method Assessment will be in form of tests and practical assignments (40%) and final written examination (60%) * SYSTEM INTEGRATION & ARCHITECTURE 11  Reference books Sage A.P. and Rouse, W.B. Handbook of Systems Engineering and management, John Wiley & Sons, 1999. * SYSTEM INTEGRATION & ARCHITECTURE 12 Key terminologies in this course Various key terminologies shall be used throughout this course as follows System Systems thinking System Integration System Architecture Project * SYSTEM INTEGRATION & ARCHITECTURE 13  System An array of components designed to accomplish a particular objective according to plan. Many sub-systems many be designed which later on are combined together to form a system which is intended to achieve a specific objective which may be set by the Project manager. * SYSTEM INTEGRATION & ARCHITECTURE 14  Systems thinking ⚫ Is a way of understanding an entity in terms of its purpose, as three steps ⚫ The three major steps followed in systems 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 whole. 3. Explain the behavior or properties of the thing to be explained in terms of its role(s)or function(s) within its containing whole (Ackoff, 1981) * SYSTEM INTEGRATION & ARCHITECTURE 15 System Integration Is the combination of inter-related elements to achieve a common objective (s). * SYSTEM INTEGRATION & ARCHITECTURE 16  System Architecture The architecture of a system defines its high-level structure, exposing its gross organization as a collection of interacting components. Elements needed to model a software architecture include: ◦ Components, Connectors, Systems, Properties and Styles. * SYSTEM INTEGRATION & ARCHITECTURE 17 What is a project? From the key terms described above, a system developer and architects cannot do anything without first establishing various projects. These projects may be new or existing. So it is inevitable to first understand what a project is, factors that influence the project, who the owners are and many more as discussed below. * SYSTEM INTEGRATION & ARCHITECTURE 18  What Is a Project? A project is a temporary endeavor undertaken to accomplish a unique product or service Attributes of projects ◦unique purpose ◦temporary ◦require resources, often from various areas ◦should have a primary sponsor and/or customer ◦involve uncertainty * SYSTEM INTEGRATION & ARCHITECTURE 19  Where do information Systems Projects Originate (Sources of Projects)? New or changed IS development projects come from problems, opportunities, and directives and are always subject to one or more constraints. 1.Problems – may either be current, suspected, or anticipated. Problems are undesirable situations that prevent the business from fully achieving its purpose, goals, and objectives (users discovering real problems with existing IS). 2. An Opportunity – is a chance to improve the business even in the absence of specific problems. This means that the business is hoping to create a system that will help it with increasing its revenue, profit, or services, or decreasing its costs. 3.A Directive – is a new requirement that is imposed by management, government, or some external influence i.e. are mandates that come from either an internal or external source of the business. * SYSTEM INTEGRATION & ARCHITECTURE 20  Projects Cannot Be Run in Isolation Projects must operate in a broad organizational environment Project managers need to take a holistic or systems view of a project and understand how it is situated within the larger organization * SYSTEM INTEGRATION & ARCHITECTURE 21 21 Stakeholders Stakeholders are the people involved in or affected by project activities Stakeholders include ◦the project sponsor and project team ◦support staff ◦customers ◦users ◦suppliers ◦opponents to the project * SYSTEM INTEGRATION & ARCHITECTURE 22 Importance of Stakeholders Project managers must take time to identify, understand, and manage relationships with all project stakeholders Using the four frames of organizations can help meet stakeholder needs and expectations Senior executives are very important stakeholders * SYSTEM INTEGRATION & ARCHITECTURE 23 Table 2-2. What Helps Projects Succeed? According to the Standish Group’s report “CHAOS 2001: A Recipe for Success,” the following items help IT projects succeed, 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 * SYSTEM INTEGRATION & ARCHITECTURE 24 24 Understanding Organizations We can analyze a formal organization using the following 4 (four) frames; Structural frame: Human resources frame: Focuses on roles and Focuses on providing responsibilities, harmony between needs of coordination and control. the organization and needs Organizational charts of people. help define this frame. Political frame: Symbolic frame: Assumes organizations are coalitions composed of varied Focuses on symbols and individuals and interest groups. Conflict and power are key meanings related to events. issues. Culture is important. * SYSTEM INTEGRATION & ARCHITECTURE 25 25  Many Organizations Focus on the Structural Frame Most people understand what organizational charts are Many new managers try to change organizational structure when other changes are needed 3 basic organizational structures ◦ Functional- ◦ project ◦ matrix * SYSTEM INTEGRATION & ARCHITECTURE 26 26 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 completing projects. A good organizational structure will allow people and groups to work effectively together while developing hard work ethics and attitudes. The four general types of organizational structure are functional, divisional, matrix and project-based. * SYSTEM INTEGRATION & ARCHITECTURE 27 Basic Organizational Structures Functional Structure - People who do similar tasks, have similar skills and/or jobs in an organization are grouped into a functional structure. The advantages of this kind of structure include quick decision making because the group members are able to communicate easily with each other. People in functional structures can learn from each other easier because they already possess similar skill sets and interests. Divisional Structure - In a divisional structure, the company will coordinate inter-group relationships to create a work team that can readily meet the needs of a certain customer or group of customers. The division of labor in this kind of structure will ensure greater output of varieties of similar products. An example of a divisional structure is geographical, where divisions are set up in regions to work with each other to produce similar products that meet the needs of the individual regions. * SYSTEM INTEGRATION & ARCHITECTURE 28 Basic Organizational Structures Matrix Structure - Matrix structures are more complex in that they group people in two different ways: by the function they perform and by the product team they are working with. In a matrix structure the team members are given more autonomy and expected to take more responsibility for their work. This increases the productivity of the team, fosters greater innovation and creativity, and allows managers to cooperatively solve decision-making problems through group interaction. Project Organization Structure - In a project-organizational structure, the teams are put together based on the number of members needed to produce the product or complete the project. The number of significantly different kinds of tasks are taken into account when structuring a project in this manner, assuring that the right members are chosen to participate in the project. * SYSTEM INTEGRATION & ARCHITECTURE 29  Basic Organizational Structures * SYSTEM INTEGRATION & ARCHITECTURE 30 30 Project Phases and the Project Life Cycle A project life cycle is a collection of project phases Project phases vary by project or industry, but some general phases include ◦concept ◦development ◦implementation ◦support * SYSTEM INTEGRATION & ARCHITECTURE 31 31  Phases of the Project Life Cycle * SYSTEM INTEGRATION & ARCHITECTURE 32 32  Product Life Cycles ⚫ Products also have life cycles ⚫ The Systems Development Life Cycle (SDLC) is a framework for describing the phases involved in developing and maintaining information systems ⚫ Systems development projects can follow ⚫ Predictive models: The scope of the project can be clearly articulated and the schedule and cost can be predicted. ⚫ Adaptive models: Projects are mission driven and component based, using time-based cycles to meet target dates. * SYSTEM INTEGRATION & ARCHITECTURE 33 33 Predictive Life Cycle Models ⚫ The waterfall model has well-defined, linear stages of systems development and support. ⚫ The spiral model shows that software is developed using an iterative or spiral approach rather than a linear approach. ⚫ The incremental release model provides for progressive development of operational software. ⚫ The prototyping model is used for developing prototypes to clarify user requirements. ⚫ The RAD model is used to produce systems quickly without sacrificing quality. * SYSTEM INTEGRATION & ARCHITECTURE 34  Adaptive Life Cycle Models ⚫ Extreme Programming (XP): Developers program in pairs and must write the tests 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. Teams often meet every day for a short meeting, called a scrum, to decide what to accomplish that day. Works best for object-oriented technology projects and requires strong leadership to coordinate the work * SYSTEM INTEGRATION & ARCHITECTURE 35 35 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 * SYSTEM INTEGRATION & ARCHITECTURE 36 36 Why Have Project Phases and Management Reviews? A project should successfully pass through each of the project phases in order to continue on to the next Management reviews (also called phase exits or kill points) should occur after each phase to evaluate the project’s progress, likely success, and continued compatibility with organizational goals * SYSTEM INTEGRATION & ARCHITECTURE 37 37  System Development Life Cycle (Kendall & Kendall terminology) * SYSTEM INTEGRATION & ARCHITECTURE 38 Topic 1 Requirements * SYSTEM INTEGRATION & ARCHITECTURE 39 Requirements A system cannot be analyzed, designed, implemented and evaluated unless the problem is understood and requirements elicited. Requirements are fundamental basis of all the system development processes. 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. * SYSTEM INTEGRATION & ARCHITECTURE 40  Sub Topics ⚫Requirements elicitation, documentation, and maintenance ⚫Modeling tools and methodologies Using Unified Modeling Language ⚫Testing * SYSTEM INTEGRATION & ARCHITECTURE 41  Core learning outcomes: Compare and contrast the various requirements modeling techniques. Distinguish between non-functional and functional requirements. Identify and classify the roles played by external users of a system. Explain and give examples of use cases. Explain the structure of a detailed use case. Detail a use case based on relating functional requirements. Describe the types of event flows in a use case and under which conditions they occur. Explain how requirements gathering fits into a system development lifecycle. Explain how use cases drive testing throughout the system lifecycle. * SYSTEM INTEGRATION & ARCHITECTURE 42 What are requirements? Requirements are statements that identify the essential needs of a system in order for it to have value and utility. * SYSTEM INTEGRATION & ARCHITECTURE 43 Characteristics of Good Req’ts 1. Describes What, Not How. 2. Atomic. i.e., it should have a single purpose 3. Unique. 4. Documented and Accessible. 5. Identifies Its Owner. 6. Approved. After a requirement has been revised, reviewed, and rewritten, it must be approved by its owner. 7. Traceable. A good requirement is traceable; it should be possible to trace each requirement back to its source. 8. Necessary. * SYSTEM INTEGRATION & ARCHITECTURE 44 Characteristics of Good Req’ts cont…. 9. Complete. 10. Unambiguous 11. Quantitative and testable 12. Identifies applicable states 14. States Assumptions. All assumptions should be stated. 15. Use of Shall, Should, and Will. A mandatory requirement should be expressed using the word shall (e.g., "The system shall conform to all state laws 16. Avoids Certain Words. The words optimize, maximize, and minimize should not be used in stating requirements, because we could never prove that we had achieved them. * SYSTEM INTEGRATION & ARCHITECTURE 45  Requirements Life cycle SPECS Analys Complet Raw Organised ed e user The Req’ts Req’ts Req’ts Req’ts User Elicitation Organisatio Analysis Prototype Transform Phase n Phase Phase Phase to spec * SYSTEM INTEGRATION & ARCHITECTURE 46  Requirement Life Cycle.. Cont.. ⚫ Elicitation Phase The starting point of the requirements engineering process is an elicitation process that involves a number of people to ensure consideration of a broad scope of potential ideas and candidate problems ⚫ Organisation Phase In this step there is no transformation of the requirements, but simple classification and categorization. For example, requirements may be grouped into functional vs. nonfunctional requirements. ⚫ Analysis Phase This represents a transformation. * SYSTEM INTEGRATION & ARCHITECTURE 47  Requirement Life Cycle.. Cont.. ⚫ Prototype Phase In this way poorly understood requirements may be tested and perhaps strengthened, corrected, or refined. This activity is often done as a proof of concept and serves to induce feedback from both the stakeholders and engineers. ⚫ Requirements documentation and specification This represents the requirements as the finished product of the stakeholder requirements team. The requirements are compiled into a requirements list or into some equivalent document format. These collected requirements are then transformed into a specification. * SYSTEM INTEGRATION & ARCHITECTURE 48 Requirements elicitation, documentation, and maintenance * SYSTEM INTEGRATION & ARCHITECTURE 49 Requirements 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. elicit * SYSTEM INTEGRATION & ARCHITECTURE 50 Requirements determination questions Requirements determination questions ◦Who does it? ◦What is done? ◦Where is it done? ◦When is it done ◦How is it done ◦Why is it done? * SYSTEM INTEGRATION & ARCHITECTURE 51 Systems Requirements Characteristics or features that must be included to satisfy business requirements ◦ Outputs ◦ Inputs ◦ Processes ◦ Timing ◦ Controls ◦ Volumes. sizes, and frequencies Data/Information collected can be about; people, organisation, work and work environment. * SYSTEM INTEGRATION & ARCHITECTURE 52 Fact – Finding Methods Sampling (of existing documentation, forms, and databases). Research and site visits. (Participation) Observation of the work environment. Questionnaires. Interviews. Prototyping. JAD/Joint requirements planning (JRP). * SYSTEM INTEGRATION & ARCHITECTURE 53  Types of Requirements ⚫User Requirements: these are statements in Natural language plus diagrams of services the system provides, together with its operational constraints. These can be categorised into 2; functional requirements and non-functional requirements ⚫Functional requirements ⚫ Describe what the system should do ⚫Non-functional requirements ⚫ Consists of Constraints that must be adhered to during development (design and implementation) ⚫ Remember ‘Constraints.’ ⚫System requirements ⚫What we agree to provide ⚫Describes system services ⚫Contract between Client and contractor * SYSTEM INTEGRATION & ARCHITECTURE 54  Functional requirements ◦ What inputs the system should accept ◦ What outputs the system should produce ◦ What data the system should store that other systems might use ◦ What computations the system should perform ◦ The timing and synchronization of the above * SYSTEM INTEGRATION & ARCHITECTURE 55 Non-functional requirements Non-functional requirements are global constraints on a computer system ◦ e.g. development costs, operational costs, performance, reliability, The challenge of Non-functional requirements: ◦ Hard to model ◦ Usually stated informally, and so are: ◦ often contradictory, ◦ difficult to enforce during development ◦ difficult to evaluate for the customer prior to delivery * SYSTEM INTEGRATION & ARCHITECTURE 56 Non-functional requirements Define system properties and constraints e.g. reliability, response time and storage requirements. Constraints are I/O device capability, system representations. Process requirements may also be specified mandating a particular programming language or development method Non-functional requirements may be more critical than functional requirements. If these are not met, the system is useless. * SYSTEM INTEGRATION & ARCHITECTURE 57 Examples of NFR Interface requirements ◦how will the new system interface with its environment? ◦User interfaces and “user-friendliness” ◦Interfaces with other systems Performance requirements ◦Time - response time ◦Throughput - transactions per second * SYSTEM INTEGRATION & ARCHITECTURE 58 Examples of NFR Security ◦permissible information flows ◦Or who can do what ◦Survivability – e.g. system will need to survive fire natural catastrophes, etc Operating requirements ◦physical constraints (size, weight), ◦personnel availability & skill level ◦accessibility for maintenance ◦environmental conditions * SYSTEM INTEGRATION & ARCHITECTURE 59 Examples of NFR Lifecycle requirements ◦ Maintainability, Enhanciability, Portability, expected market or product lifespan limits on development ◦ E.g. development time limitations, resource availability and methodological standards. Economic requirements ◦ e.g. restrictions on immediate and/or long-term costs. * SYSTEM INTEGRATION & ARCHITECTURE 60  Requirements Documentation There are basically two types of documents realised from the requirements elicitation phase. These include; ◦User Requirements Specification Document ◦System requirements specification Document * SYSTEM INTEGRATION & ARCHITECTURE 61  User Requirements Specification –URS/URD ⚫ The URS document outlines precisely what the User (or customer) is expecting from this system. ⚫ User Requirement Specification may incorporate the functional requirements of the system or may be in a separate document labelled the Functional Requirements Specification - the FRS. The URD has the following information: 1. Functional Requirements 2. Non-Functional Requirements * SYSTEM INTEGRATION & ARCHITECTURE 62  System Requirements Specification Document A detailed description of the system services. What do we agree to provide? A structured document setting out detailed descriptions of the system services. Written as a contract between client and contractor. * SYSTEM INTEGRATION & ARCHITECTURE 63 TOOLS THAT AID IN DEVELOPING & UNDERSTANDING SYSTEM REQ’TS Affinity diagrams Force-field analysis Ishikawa fishbone (cause-and-effect) diagrams Pareto diagrams Pugh charts Quality function deployment (QFD) * SYSTEM INTEGRATION & ARCHITECTURE 64  Comparison of the tools * SYSTEM INTEGRATION & ARCHITECTURE 65