Courses/Computer Science/CPSC 203/CPSC 203 Template/Lecture Template/Lecture 5
Contents
Housekeeping
Required Reading
The required readings from the textbook fluency ... are:
- Chapter 14. Fill-in-the-Blank Computing. pp 374-406.
- Chapter 15. "What If" Thinking Helps. pp 411 -437.
Also -- it is assumed you are up-to-date on online Lab Manual readings.
Introduction
The next few weeks of lectures will deal with Information Systems. Our stand in for "Information Systems" will be Spreadsheets and Databases. In tutorials, you will be learning how to use these technologies. In lectures, we will focus more on "how to think about problem solving". That is, we will be using spreadsheets and databases as a medium for problem solving, in the context of Information Systems.
To frame the next few lectures, we will first introduce some new concepts:
- Information System
- Information Hierarchy (Data, Information, Knowledge, Wisdom).
Then, we will go through the process of building a simple graph model of spreadsheets (as a way of thinking about their capabilities and limitations).
Finally we will go through an extended example of how Spreadsheets in particular are a medium for "problem solving on the fly" ... that is, rapidly moving from an initial idea to a solution.
At the end of this lecture you will:
- Understand the concepts of an Information System, and an Information Hierarchy.
- Have an initial idea of how spreadsheets can contribute to Information Systems, and provide a medium that allows us to leverage the Information Hierarchy.
- Understand a graph model representation of the basic capabilities of a spreadsheet.
- Appreciate how a spreadsheet can be used as an "idea sketch pad".
Glossary
- Spreadsheet: Row by column array of cells. Values are passed from cell to cell.
- Cell: "Atomic" unit of spreadsheet. In a cell there is data (values), formats (how cell looks) + data types (what kind of value: integer, text...etc)
- Operator & Function: Works on values to transform them.(i.e. +, -, X...)
- Domain: Cells from which values are taken.
- Range: Cells to which data is given.
- Case: A unit of observation
- Variable: An observed attribute
- Properties -- the interface attributes of a cell: e.g. borders, fonts, shading, data types.
- Value(s) -- the value a cell holds, which it can pass onto another cell.
A Brief Cartoon History of Spreadsheets
- Invented by Dan Bricklin in 1978, called Visicalc
- A Brief History of Spreadsheets: http://dssresources.com/history/sshistory.html
- Originally used for accounting and financial information
- Lotus 1-2-3 developed by Mitch Kapor integrated charting, plotting and database-like capabilites, and spreadsheets became a general analysis and modelling tool.
- Today's spreadsheets have added many bells and whistles, but essentially have the same functionality as Lotus 1-2-3 developed well over 20 years ago.
Concepts
Information Systems and the Information Hierarchy
- Information System: A system that is focussed on information. Information is essentidally data that has some meaning or context. In an information system, the elements are now:
- People (users),
- Technology (hardware, software, communications),
- Data (raw material for information) and
- Procedures (rules and algorithms)
- Information Hierarchy. The process by which "raw data" is analyzed and synthesized in the context of information systems (see above). Often represeted as a pyramid where from the bottom up:
- Data are the basic observations, facts, measurements ...
- Information are aggregations, summaries, statistics based on data; usually with respect to a particular problem that is attempting to be solved.
- Knowledge is the recognition of patterns and relationships amongst information (which are often summarized in a model).
- Wisdom is .... is ... ..... is hard to define in a technical sense, but can be seen as a the pinnacle of the Information Hierarchy, the wise use of knowledge for a particular purpose.
- In a sense the transition from Data-->Information, Information-->Knowledge, Knowledge---> Wisdome can be seen as following a general pattern:
- Information is the identification of relations amongst data
- Knowledge is the identification of relations amongst information
- Wisdom, in this sense, could be seen as the identification of relations amongst Knowledge. (This likely does not capture all the nuances of wisdom).
- For more on the Information Hierarchy, see:
In the context of the Information Hierachy and Information Systems, spreadsheets are an important resource because:
- They are media that can rapidly capture data, and information
- They provide an idea sketch-pad where ideas can be worked out and tested on data
- They have, in their functional model, and intuitive cause-effect interface, that naturally leads to "What If" scenarios.
Spreadsheet Data Model
- cell X -----> cell Y
- Domain X -----> Range Y
- Dots -- the cells
- Edges -- Operators and Functions
- Properties of a Spreadsheet Cell:
- Format (i.e. colour, shading, background, font-size)
- Type (i.e. data type)
A Spreadsheet is a "lattice" or "grid" of cells. Functions and operators allow values to be moved from cell to cell. A cell can not write back into itself. Essentially a spreadsheet is a very user friendly programming environment.
Spreadsheets as Idea Sketch Pads
The use of Spreadsheets as an idea sketch pad, is best illustrated by an example.
The problem we are trying to solve is this:
- We know how to calculate the derivative of a well defined equation (say for a process).
- But, what if we are not given the "equation" but only have our observations on the process (i.e. the DATA).
- Can we come up with a process for turning data into equations (i.e. using the equation as a summary, or INFORMATION).
- Can we generalize this process?? (If it applies to a broad range of data, we might have a new kind of analysis that will work for all data of a particular pattern, thus creating KNOWLEDGE).
Our example shows how a bit of "playing around" in spreadsheet mode, combined with the judicious use of a bit of data, simple summary statistics, can lead to the birth of a new kind of analysis.
Media: Example_IntervalCalculus.xls
Media: Example_IntervalCalculus.doc
Summary
- We introduced the concepts, Information Systems, and Information Hierarchy.
- We reviewed a graph model of spreadsheets.
- We illustrated how spreadhsets can be used as an idea sketch pad, and in particular as a medium that allows us to scale the information hierarchy.
Text Readings
see Required Readings above.
Resources
The Elements of Spreadsheet Style. 1986. By J.M. Nevison (Great, cheap, book on spreadsheet design. Out of print, but easily ordered from Amazon).
A Brief History of Spreadsheets: http://dssresources.com/history/sshistory.html A nice little article on the origins of spreadsheets by some guys with too much facial hair.
Another overview on Spreadsheets is at: http://en.wikipedia.org/wiki/Spreadsheet
