Skip to content

Latest commit

 

History

History
261 lines (185 loc) · 12 KB

Systems_Analysis.md

File metadata and controls

261 lines (185 loc) · 12 KB

Systems Analysis

author: Brian High date: January 15, 2015 transition: fade #incremental: true

Research Computing and Data Management

http://github.com/brianhigh/research-computing

This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Creative Commons License

Systems Development Life Cycle

We will take a closer look at the systems analysis phase.

Source: [Wikipedia](http://en.wikipedia.org/wiki/Systems_development_life_cycle#Phases), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)

SDLC cycle

Source: [Dzonatas, CC BY-SA 3.0, (Wikimedia)](http://commons.wikimedia.org/wiki/File:SDLC-Maintenance-Highlighted.png)

What will you need?

A primary goal of this course is to help you develop your skills in requirements analysis.

  • These skills enable you to:
    • Clarify of your project needs
    • Plan your project
    • Obtain and allocate critical resources

If you don't know what you need, how can you ask for it?

Systems Analysis

Imagine we have already:

  1. Completed initial feasibility study
  2. Proposed the project
  3. Gained approval from from stakeholders to proceed

Now, our Systems analysis will:

  • Break down the system in different pieces
  • Analyze the situation and project goals
  • Break down what needs to be created
  • Engage users to state definite requirements
Source: [Wikipedia](http://en.wikipedia.org/wiki/Systems_development_life_cycle#System_investigation), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)

Systems Analysis Definition

  • system = "a set of interacting or interdependent components"1
  • analysis = "to take apart"2

Systems analysis is a problem solving technique that decomposes a system into its component pieces for the purpose of the studying how well those component parts work and interact to accomplish their purpose.3

Lonnie D. Bentley


1. Source: [Wikipedia](http://en.wikipedia.org/wiki/System), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)
2. Source: [Wikipedia](http://en.wikipedia.org/wiki/Systems_analysis), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)
3. Source: *Systems Analysis and Design for the Global Enterprise 7th ed.*, by Lonnie D. Bentley, as quoted by [Wikipedia](http://en.wikipedia.org/wiki/Systems_analysis)

Systems Analysis Phases

systems analysis phases

  1. Scope definition: Establish system boundaries
  2. Problem analysis: Identify symptoms and causes
  3. Requirements analysis: Determine goals
  4. Logical design: Model relationships
  5. Decision analysis: Evaluate alternatives
Source: [Wikipedia](http://en.wikipedia.org/wiki/Systems_analysis#Information_technology), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)

Scope Definition

Scope involves getting information required to start a project, and the features the product would have that would meet its stakeholders requirements.

  • Project Scope: work to be done
  • Product Scope: desired features and functions

Scope creep is [...] the incremental expansion of the scope of a project [...], while nevertheless failing to adjust schedule and budget.

Source: [Wikipedia](http://en.wikipedia.org/wiki/Scope_%28project_management%29), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)

Problem Analysis

  • Define and clarify the problem (or issue)
  • Determine the problem's importance
  • Assess the feasibility of solving the problem
  • Consider any negative impacts (unintended consequences)
  • Prioritize problems to solve (bottlenecks? low-hanging fruit?)
  • Answer: what, why, who, when, where, and how much?
  • Find causes (especially root cause) and symptoms (effects)
Source: [Jenette Nagy, Kansas University, CC BY-NC-SA 3.0 US](http://ctb.ku.edu/en/table-of-contents/analyze/analyze-community-problems-and-solutions/define-analyze-problem/main)

Root Cause Analysis

"Ask Why Five Times"

Ask Why Five Times

Source: [KellyLawless, CC BY-SA 3.0 Unported (Wikimedia)](http://commons.wikimedia.org/wiki/File:Root_Cause_Analysis_Tree_Diagram.jpg)
See also: [Ask Why 5 Times, Business Analysis Guidebook/Root Cause Analysis (Wikibooks)](http://en.wikibooks.org/wiki/Business_Analysis_Guidebook/Root_Cause_Analysis#Ask_Why_5_Times)

Requirements Analysis

Source: [Wikipedia](http://en.wikipedia.org/wiki/Requirements_analysis), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)

Types of requirements:

Requirements Modeling: Example

Survey Data System

Behavioral requirements ...

  • Researcher uploads survey.
  • Subject takes survey.
  • Subject uploads results.
  • Researcher downloads results.

... in role goal format.

Use Case Diagram

research survey data system

Source: [Brian High, Github](https://github.com/brianhigh/data-workshop/blob/master/images/research_survey_data_system.png), [Public Domain, CC0 1.0](http://creativecommons.org/publicdomain/zero/1.0/)

Logical Design

Source: [Wikipedia](http://en.wikipedia.org/wiki/Systems_design#Logical_design), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)

Entity Relationship Diagram

  • Artist performs song

artist performs song

Source: [Bignose, Wikimedia](http://commons.wikimedia.org/wiki/File:ERD-artist-performs-song.svg), [Public Domain](http://en.wikipedia.org/wiki/Public_domain)

Logical Design: Diagrams

Several examples of these diagrams can be found in Systems Analysis and Design.

This tutorial1 (PDF, HTML, MP4) provides several examples from a fictitious public health research study.

1. See also: *[Data Management](https://canvas.uw.edu/courses/951183/modules)*, UW Canvas.

DFD and ERD

Source: [Brian High, Github](https://github.com/brianhigh/data-workshop/blob/master/images/analysis_and_design.png), [Public Domain, CC0 1.0](http://creativecommons.org/publicdomain/zero/1.0/)

Decision Analysis

Decision analysis involves ...

  • Presentation of alternatives:
    • What to buy or build?
  • Evaluation of alternatives:
    • Assess the "pros and cons"
    • Compare against requirements
  • Make a recommendation to stakeholders
  • Get a decision from stakeholders
Source: [Wikipedia](http://en.wikipedia.org/wiki/Decision_analysis), [CC BY-SA 3.0](http://en.wikipedia.org/wiki/Wikipedia:Text_of_Creative_Commons_Attribution-ShareAlike_3.0_Unported_License)