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Transcript of 11 COSC 2810 Systems Analysis and Design ●Instructor: Quinn Shao ●E-mail:...
11
COSC 2810 Systems Analysis and Design
● Instructor: Quinn Shao● E-mail: [email protected]● Online course info:
http://ereserves.webster.edu (Electronic Reserves and Course
Materials)
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What is System Analysis and Design?
● Step by step process developing high- quality information system.
What is information system?● Combination of 1. IT 2. People 3. data
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Introduction
● Companies use information as a weapon in the battle to increase productivity, deliver quality products and services, maintain customer loyalty, and make sound decisions.
● Information technology can mean the difference between success and failure
Figure 1-1
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The Impact of Information Technology
● Information Technology – Combination of hardware and software
products and services that companies use to manage, access, communicate, and share information
– A vital asset that must be used effectively, updated constantly, and safeguarded carefully
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The Impact of Information Technology
● The Future of IT– Responsible
for half of all productivity growth and a third of all economic growth between 1995-1999
Figure 1-3
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The Impact of Information Technology
● The Role of Systems Analysis and Design– Systems Analysis and Design
• Step-by-step process for developing high-quality information systems
– Systems Analyst• Plan, develop, and maintain
information systems
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Information System Components
● A System is a set of related components that produces specific results
● Information systems have five key components: hardware, software, data, processes, and people
Figure 1-6
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● Hardware – Everything in the physical layer of the
information system (server, workstation, network, computer, devices)
– Moore’s Law accurately predicted that computer processing power would double every 18 to 24 months
Information System Components
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Information System Components
● Software– System software (OS, security SW)– Network operating system (NOS)– Application software (Word, Access, Spreadsheets)
– Enterprise applications (order processing SW,
Payroll sys.)– Horizontal system (can be adapted for use in many
different companies, inventory sys. Payroll sys.)– Vertical system (special purpose sys.: web-based
retailer, medical sys.)– Legacy systems: a new sys. Must be able to
exchange data with older application)
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Information System Components
● Data – The raw
material that an information system transforms into useful information (database)
Print a paycheck by linking different database tables
Figure 1-11
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Information System Components
● Processes – Describe the tasks and business functions
that users, managers, and IT staff members perform to achieve specific results
● People– Users, or end users, are the people who
interact with an information system, both inside and outside the company
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The primary purpose of an information system is to provide valuable info to users.
Success or failure of a system depends on whether user are satisfied with the
sys’s output and operations.successful info. depends on the skilled professionals like, sys. analyst, programmers, DBAs.
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Understanding The Business
IT professionals must understand a company’s business operations in order to design successful systems. (a retail store or a hotel chain has unique info sys. requirements)
● Business Profile– Overview of a company ( products, service
through interview)● Business Models
– Graphical representation of one or more business processes
Figure 1-12
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Understanding The Business
● New Kinds of Companies● Companies are classified based
on their main activities:– Production-oriented (Intel, Motorola,
Cisco)– Service-oriented (Oracle, Amazon.com,
Office Depot)– Brick-and-mortar (traditional companies)– Dot-com (.com)
Figure 1-14
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Impact of the Internet
● E-Commerce (I-Commerce) - electronic commerce
– Internet-based commerce
● B2C (Business-to-Consumer)– Consumers can go online to purchase a
variety of products and services
● B2B (Business-to-Business)– Enables smaller suppliers to contact large
customers and allows purchasers to obtain instant information about market prices and availability
(Ford buy Firestone tires, builders buy lumber)
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Types of information system
● Today, Systems are identified by its functions, rather than by users – Enterprise computing systems– Transaction processing systems– Business support systems– Knowledge management systems– User productivity systems
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Types of information system
● Enterprise computing systems– Information systems that support
company-wide operations and data management
– To integrate a company’s primary functions (production, sales, services, inventory control, and accounting)
Figure 1-17
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Types of information system
● Transaction processing systems– Process data
generated by day-to-day business operations: customer order processing, accounts receivable, warranty, claim processing
Figure 1-18
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Types of information system
● Business support systems– Provide job-related information to users
at all levels of a company (travel pattern of rental car on holiday weekend)
– Use What-if analysis to increase profit. (add charge to bad weather delivery or
overload delivery)
Figure 1-19
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Types of information system
● Knowledge management systems– Simulate human reasoning (strict logic
and fuzzy logic)
Figure 1-20
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Types of information system
● User productivity systems– Technology that improves productivity: e-
mail, voice mail, fax, video conference, internet to
share data
● Information systems integration– Most large companies require systems that
combine transaction processing, business support, knowledge management, and user productivity features:
Combination of different types of info system.
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Systems Development Tools and Techniques
● Systems analysts must know how to use a variety of techniques such as modeling, prototyping, and computer-aided systems engineering (CASE )tools to plan, design, and implement information systems
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Systems Development Tools and Techniques
● Modeling– A system analyst can describe and simplify
an information system by using a set of business, data, object, and process models.
– A business model describes the info that a sys must provide.
– A data model describes data structure and design
– An object model describes objects (combine data and processes)
– A process model describes the logic a programmer uses to write modules.
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Systems Development Tools and Techniques
● Prototyping– Early working version of an information
system as an initial model to evaluate finished sys.
– Speeds up the development process significantly
– Can be an extremely valuable tool but can be made too early before IT issues are fully understood.
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Systems Development Tools and Techniques
● Computer-Aided Systems Engineering (CASE) Tools (Tool kit part 2)– CASE uses powerful software to help
systems analysts develop and maintain information systems
Microsoft Visio for drawing charts, diagrams.
Figure 1-22
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Systems Development Methods
● Structured Analysis– traditional systems development technique – Uses the Systems Development Life Cycle
(SDLC) to plan, analyze, design, implement, and support an information system. F1-25 shows a process that accepts
input data from 2 sources and transforms it into output data.
Figure 1-25
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Systems Development Methods
● Object-oriented (O-O) analysis– combines data and the processes that act
on the data into things called objects– Systems analysts use O-O to model real-
world business processes and operations
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Systems Development Methods
● Joint Application Development and Rapid Application Development– JAD – Team based fact finding– RAD – compressed version of the entire
process(More details about JAD and RAD in Chapter
3)
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Systems Development Methods
● Other development methodologies– In addition to structured analysis and O-O
methodologies, you might encounter other systems development techniques
– Microsoft Solutions Framework (MSF) documents the experience of its own IT teams
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The Systems Development Life Cycle
● SDLC used to plan and manage the systems development process.
● It includes the following steps:1. Systems planning2. Systems analysis3. Systems design4. Systems implementation5. Systems operation and support
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The Systems Development Life Cycle
● Systems planning– Purpose is to identify the nature and
scope of a problem. – Systems request – begins the process &
describes problems or desired changes.– Systems planning includes preliminary
investigation, which is a feasibility study that anticipates cost and benefit. Make recommendations on technical, economic, and time factors.
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The Systems Development Life Cycle
● Systems Analysis– Purpose is to build a logical model of the
new system– First step is requirements modeling,
where you investigate business processes and document what the new system must do. (through interview)
– End product is the System requirements document.
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The Systems Development Life Cycle (SDLC)
● Systems Design– Purpose is to create a blueprint that will
satisfy all documented requirements– Identify all inputs, processes and outputs– Avoid misunderstanding through
manager and user involvement– End product (document) is system design
specification
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The Systems Development Life Cycle
● Systems Implementation– New system is constructed– Implement, test, & install systems– File conversion occurs– Users, managers, IT staff trained to
operate and support the system– System evaluation performed (if sys
works properly)– Outcome of this phrase: system is ready
for use
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The Systems Development Life Cycle
● Systems Operation and Support– IT staff maintains and enhances the
system– Enhancements provide new features and
benefits– Well-designed system will be reliable,
maintainable, and scalable
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The Systems Development Life Cycle
● Systems Development Guidelines– Stick to a plan, complete phases in sequence– Involve users, fully understand user’s
requirements– Identify milestones for proceed or reject– Establish checkpoints to ensure project on
schedule– Be flexible, sys development is a dynamic
process– Provide accurate and reliable cost and
benefit information
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Information Technology Department
● The information technology (IT) department develops and maintains a company’s information systems. IT structure:
Figure 1-30
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Information Technology Department
● Application Development– Team may include users, managers and
IT Staff members
● Systems Support– Provides hardware and software support
● User Support– Provides users with technical information,
training, and productivity support
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Information Technology Department
● Database Administration– Database design, management, security,
backup, and user access
● Network Administration– Includes hardware and software
maintenance, support, and security
● Web Support– Design and construction of web pages
and presence. Important for e-commerce
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The Systems Analyst Position
● A systems analyst investigates, analyzes, designs, develops, installs, evaluates, and maintains a company’s information systems
● On large projects, the analyst works as a member of an IT department team.
● Smaller companies often use consultants to perform the work
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Chapter Summary
● IT is a combination of hardware, software, and telecommunications systems that support business
● The essential components of an information system are hardware, software, data, processes, and people
● Companies are production oriented, service oriented, or a combination of the two.
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Chapter Summary
● Based on their function and features, information systems are identified Organization structure usually includes levels
● Systems analyst use modeling, prototyping, and CASE tools
● Various development methodologies exist, including structured analysis and object-oriented analysis
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Chapter Summary
● The Systems Development Life Cycle1. Systems planning2. Systems analysis3. Systems design4. Systems implementation5. Systems operation and support
● An IT department develops, maintains and operates a company’s information systems
● Systems analysts need a combination of technical and business knowledge, analytical ability, and communication
Chapter 1 Complete