- Systems Development Life Cycle - seven stages - each waterfall stage must be complete before the next stage can begin
- Identify problem, objective
- Determine info requirements
- Analyze system needs
- Design recommended system
- Develop and document software
- Testing and maintaining system
- Implementing and evaluating system
The process of analysis a business problem that can be solve with an information system. Phases are:
Analysis - system analysis phase 1
Defining the information requirements
Leading cause of system failure and cost overrun is inaccurate requirements
- Identify problem, objective
- Determine info requirements - product requirements; project requirements
- Analyze system needs - recommendation document is end result of the analysis phase
Design - system analysis phase 2
Two main methods for modeling and designing in the system - object-oriented and structured
- Design recommended system -how will work and primary output; what where stored; infrastructure needed
- Develop and document software
Object oriented Systems development
In the design phase of system anaylsis.
Uses the object as the unit of design and is based on concepts of class and inheritance
Classes can inherit from other classes
Structured Systems - design phase of System Analysis
Models are methodical and process-oriented, moving from the general level to the specific level through a series of processes.
Implementation - phase of System Analysis Phase 3
Testing, user training, maintenance and documentation of the system.
- Test and maintain system
- Implement and evaluate system
What other items to consider before starting the system analysis.
- recommend feasibility study - to determine even if affordable, technology possible and organizationally feasible or possible.
- Position changes
- Role changes
- Skill set
- Process changes
- Completion for org resources
- Competing projects and stakeholder interests
Other SDLC Models
- Fountain model - allows for activity overlap
- Spiral model - recognizes the need to review or repeat earlier states as project progresses
- Build and fix - simplest allowing for code to be incremental modified until successful
- Prototyping mode - scaled prototype that can be tested prior to full scale dev
- Incremental model divides the product into sections that are user-tested at each stage-gives fewer errors
Product Requirements for determining information requirement
- Criteria that must be met by the product
- What it should do, look, last,easy to use
- what resources are needed for project completion
- How will the project be implemented
Methods of obtains user requirement
- Analyze existing system
- Perform analysis of the area
- Experiment with the system during dev
User requirements analysis must achieve what?
- Input output processing steps and data storage needs
- Vol of data to be handled dB capacity needed and what level of service
- Interface needed for user interaction
- Control measures needed
Must be considered before beginning system analysis
4 categories of organization change when changing the information system
- Automation - most common
- Rationalization - process of reducing bottlenecks in process and procedures
- Business process redesign - analysis simplification and redesign of org processes
- Paradigm shift - radical for of change in which nature of or is completely changed
SDLC pros cons
Ease of maintenance, ability to survive IS staff change
Bad - inc dev cost time, rigidity, difficulty of cost estimation
Adv - clear objectives, strict approval, progress measurement, stability
Dis - difficulty n responding to change, time intensity, inability to easily return to previous stage
Two Primary Types of SDLC
Project and Product
Additional system development methods besides waterfall
Iterative development models agile
End user development is what?
Alternative to waterfall approach
- Informal solution dev by end users
- Fourth gen languages need little tech assistance
Iterative development is what? Agile
Alternative to waterfall
- Dev sys requirements and solutions through collaborative self organized cross functional teams
- Encourages adaptive planning and dev
- Fast delivery
- Continuous improve
- Flexibility to change
Prototyping is what?
- Alternative to waterfall
- Four step process
- Experimental systeminexpen and quick built and provided to end users for eval then refined
- User requirement
- Dev prototype
- Using pro type
- Refine prototype
Scrum is what?
- Alternative to waterfall
- An incremental form of agile software
- Recognizes that customer needs change throughout project
- Changes can be quickly addressed.
- Team members are loc in end user facility to facility communicating
RAD is what?
Rapid application development
An iterative alternative to waterfall mode of software dev
- This approach to software dev focuses on dev process
- Limited emphasis on planning process
- Emphasizesneed to adjust project req as the project progresses
- Uses prototypes to determine specification
- Allows adaptability
- Well suite for soft dev that is drive by GUI requirements
What is water fall method?
- Traditional sys dev - used when sys req are clean, unlikely to change, tech not likely to change, short term, sufficient resources and skills
- Each stage completed before next stage
- Sysanalysis - req, feasibility study and rules of models, schema and business rules
- System design - software architecture req for the app
- Programming - software dev, proving and integration
- Testing - debugging
- conversion -
- Production and maintenance
Modern models of SDLC
- Fountain - waterfall but with overlapping stages
- Build and fix
Areas of the feasibility study
- Economic - TCO
- Operational - is system compatible with existing or proposed operations of the org
- Schedule - will the project be viable when completed if long term impl schedule
- Legal - data confidentiality
- Political - how will political stakeholders respond to changes
Critical Path Method - step by step process planning techniques that defines critical/non critical tasks with a project in order to reduce process delays and time related problems
Uses Work Breakdown Structure (WBS), time req per activity, dependencies between the activities and logical deadlines for each deliverable milestone.
Work Breakdown Structure
Broken down list of all deliverables showing what customer will get at end of project
What happens after the CRM structure is built?
Longest paths and dates are calculated - activity on a arrow/node (PERT chart [program eval and rev technique)
Critical path determines project duration
- Able to represent the shortest amount of time in which the project can be completed.
- Tasks charted to show order can have critical and sub critical paths and non critical paths
- Each path is Calc separately. Longest path is critical path.
- Project schedule is sensitive if:
- More than one critical path
- Critical path will likely change
Expressed through domain models and class models as a static view of objects and entities that make up an info system model.
Models user requirements
Domain model represents the definitions of concepts of the problem and defines relationships of the entitie
Class model helps visualize static entities and relationships between them
What language is used to depict a system model (logical model)?
Depicted using Unified Modeling Language to make diagrams charts and maps
UML helps visualize and analyze an info sys architecture
UML models static structures and dynamics as well as behavior of systems
What is a system model steps?
- Collect info about the proposed system
- Info gained is used to develop functional flow diagrams, functional specification and flow dictionary
- Functional flow diagrams are then presented to the reviewer and can be revised due to input at this stage
Solution Evalution Tools
Feedback from others who have implemented the system
- EMS electronic meeting system to discuss alternatives - same as GSS group support system
- Group should be a broad representation of stakeholder including exec, experts and intended users
Process documentation tools
It documents the detail of a function and represents the processing steps in a logical format
- Modular design combination of sequence, selection and lopping
- Decision tables- all combinations of conditions and actions in a logical structure
- Decision trees - graphical representations of the rules, conditions and actions of the decision table - every possible outcome
- Pseudo code - uses sequence, selection and looping along with limited use of data terminally to describe the process
The 3 levels of risk with system design and implementation
- Project structure
- Project size
- Staff technical capabilities
3 cut over or implementation methods
Direct implementation - old system replaced by new system wo any rollout or overlap. Only good when it is a non critical system or it has been tested prior to implementation
Parallel adoption - both systems operated at same time
Prototyping - user gets to test drive a sample, disadvantage is the additional time and cost in developing a prototype
Intelligent Character Recognition
- Not 100%
- Learns different fonts and handwriting styles to improve accuracy and recognition
- More accurate than ocr
Electronic point of sale
Electronic funds transfer point of sale - magnetic strip
Both data capture methods
Factors to consider when choosing an implementation method
- Critical nature of the system
Commercial off the shelf system
System implementation should contain 5 of 6 items what are they
- Software development
3 types of system testing phase
Unit testing - testing each program in the system
System testing - testing the system as a whole
Acceptance testing - involves end user evaluation. Is it ready to go live.
System implementation is another name for
System Performance Evaluation
Conducted after implementation.
Important to do a periodic eval of the information system to determine if it is effective and relevant to the organization.
The process of gathering and analyzing information to compare performance with predetermined objectives and if they were achieved.
What are three type of system evaluations
System-oriented -the ability of an information system to discriminate between files or data that are relevant to a user query and those that are not. Uses measures of precision and recall.
Function-oriented-determination of success of the system to meet functional objective. Confirm quality and functionality of the outputs.=quality and usefulness, user satisfaction, efficiency
Strategy oriented - the determination of whether the system outputs enable management to make strategic decisions that will achieve org vision.
Increase User adoption after implementation - 6 methods of user support
- Benchmarking - ask users who have gone before what are good best practices
- Usability testing - formal meeting with several users interview
- User communication - user inputs
- Forming an internal user group
- Planning - identifying and preparing for future needs in order to prepare and budget for future upgrades and mods
- Leveraging existing resources - manuals,Internet forums, addl training
4 types of system maintenance
- Corrective - fix errors
- Perfective - increase efficiency
- Preventive - reduce chance of system failure
- Adaptive - add new capabilities to the system
What is system level security
The security that protects systems from event and processes that violate the system.
- Login credentials
- Antivirus software
5 criteria for providing access to a file or system level
- Transaction type
3 primary area of information security are
- Authentication and authorization
- Prevention and resistance
- Detection and response
Which risk might affect the project or documents
Involves the measurement of the probability and consequences of risk and estimating effect on proect
Performing an analysis of the risks in order to prioritize the effects on a project
Risk response planning
Involves the development of procedures that enhance opportunities to reduce threats to system or project
Risk management strategies
- Promoting project leadership skills
- Learning from previous projects and experience
- Knowledge sharing
- Creating a project management culture
- Change agent
- Problem solver
- Analyze processes
- Perform system testing
- Deploy system
- Develop user manuals
- Not a business analyst but should know business processes
CASE tools and features
Computer aided software engineering - the use of computer methods to organize and manage software development in is.
Got tools, workbenches and environments
- Upper case - support as and modeling
- Lower case - support dev activities
- Workbenches - combine several tools for software dev to achieve simple interface and integration of data and control - visual basic
- Environments - combine multiple tools or workbenches to support the software cycle.
6 types of CASE tools (same for workbenches)
- Config mgmt
- Project mgmt
5 categories of CASE environments
- Tool kits - tools for integration
- 4th gen - focus on interface driven applications
- Language centered - single language basis useful for research and prototyping
- Integrated - entire SDLC
- Process centered - most resourceful category capability of specifying analysis and design and software control process
Allows application software to be stored in one or more locations to be accessed and operated using internet enabled devices
Can be public, private or hybrid
Relies on shared resources to achieve scale through shared services and a converge infrastructure
Users lease hardware and software - reducing capital expenditures; increase deployment speed, flexibility and profitability.
Typically owned and run by service providers like amazon and google often in collocation facilities
Owned and run by or merely dedicated to the org whose data resides on the equipment
Cloud operations that have elements of both public and private clouds.
Reuter’s to the internet sites that emphasize usability,interoperability and user generated content.
First gen web sites were passive viewing and downloading only
2.0 enable collaboration and interaction amoung users in a social media dialogue creating a virtual online community
Benefits of cloud computing
Share or reuse software and code - such as common operations for storage and converting into among formats and manipulation
Prototype tools enabling sa to test or pilot software in order to asses if it is appropriate for the project
RSS feeds (Rich Site Summary) are used by publishers for periodic dissemination of in inc new blog entries summaries
3 levels of risk associated with system design
Staff tech abilities
Internet published newsletters cover what?
A specific topic