Distance Learning on Forty Cents a Day

1
Distance Learning on Forty Cents a Day

• John Sullins
• Department of Computer Science and Information
  Systems
• Youngstown State University

2
Overview

• Goal Enable students with time conflicts to
  take courses
• Asynchronous Learning
• Powerpoint slides for lectures
• Recorded summaries of lectures
• Downloaded and used together by distance learning
  students
• What was learned
• Ideas for recording lectures
• Best practices for exams and presentations
• Effects on in-class students
• Workload involved

3
The Situation Then

• Course
• CSIS 5857 Encoding and Encryption
• Elective for undergraduate and graduate students
• Emphasis on mathematics and algorithms
• Offered Spring 2007, MW 300 415
• Time conflict for several graduate students
• Most CSIS graduate students work full time
• Security topics of most interest to these
  students
• Students asked for distance learning option in
  January
• Too late to reserve distance learning classroom
• No time to acquire distance learning equipment

4
The Situation Now

• Fall 2007
• CSCI 5895 Artificial Intelligence in Game Design
• Emphasis on concepts and design
• Some programming
• CSCI 6962 Server-side Design
• Heavy emphasis on programming

5
Procedure Summary
Slides prepared for lecture
Recorded lecture summary
Lecture given to in-class students
Class contributions to lecture
Recording posted to web site
Corrections made
Slides posted to web site
Slides and recording downloaded by student
6
Recording Procedure

• Synchronized with slides
• Separate recording for each slide
• Introduce slide
• Describe slide
• Tell to go to next slide
• Edited together to create entire lecture
• Usually shorter than actual lecture
• 75 min. lecture ? 20 30 min. recording
• 50 min. lecture ? 15 20 min. lecture

7
Recording Procedure
In this slide we will introduce a potential
weakness of RSA if it is used to send very short
message, particularly if an adversary knows the
form of that messagePlease go to slide 5
In this slide, well do an example of a short
message attack. Lets say that Darth knows that
Bob will send Alice a Social Security Number
(which he knows is exactly 9 digits), encrypted
with her public key. Lets also suppose that
Darth knows that public key Please go to slide 6
In this slide, well see how Darth can use
Alices public key to encrypt all possible social
security numbers and store them in a big table.
Since there are only a billion or so, this can
easily be done Please go to slide 7


8
Listening to Lectures

• Course web site provides slides and audio files
  of recordings
• Student downloads files
• Listens to recording
• Follows along with slides
• Useful idea Create introductory lecture
• Gives students practice in following along with
  lecture and slides
• Early detection of technical difficulties
• Allows students to give quick feedback about
  lecture style

9
Recording Lectures

• Recorded soon after in-class lecture
• Made recording smoother, as talk already given
  once
• Allowed correction of slides
• Mistakes found during lecture
• Mistake-free slides more crucial for on-line
  students
• Allowed summary of in class discussion to become
  part of recording
• More complete coverage of topic
• On-line students become more of a part of class
• Important to write these down immediately after
  class!

In class, a student made the point that while
you may need to present numbering in
international formats, you may want to keep
currency in dollars rather than pounds or Euros.
In that case, you would use get NumberInstance
rather than getCurrencyInstance to set the format
of the numbers.
10
Recording Software

• Software
• Microsoft Sound Recorder
• WavePad
• Both allow files to be appended together to
  create entire lecture form short recordings
• Recording properties
• Sample rate important
• Too low ? recording unintelligible
• Too high ? Files too large for fast download
• Best compromise11.025 kHz, 16 Bit, Mono
• Record and test yourself!

11
Slide Creation

• Must be detailed enough to allow student to get
  information from both slides and voice
• More difficult to understand speech over internet
  than in person
• Key question Could you get gist of lecture from
  just slides?
• Some ideas
• Ask question, answer question
• Introduce procedure, then show step by step

12
Slide Creation

• Most time consuming part of process!
• Shortcuts
• Screenshots
• Slides from textbook site
• Should not do this the first time you teach a
  course!

13
Exams for Distance Students
Me

• Exams emailed to students as Word document
• Should test ability to receive, open, and save
  document in advance
• Agree in advance on day/time
• Must be available to answer questions via email
• Provide more time
• Will be using word processor instead of writing
• Will need to scan drawings
• Usually multiply time by 1.5
• Students email document with answers back
• Send receipt indicating you received it!

Document containing exam
Document containing answers
Emails with questions
Student
14
Exams for Distance Students

• No way to proctor exams
• Trust students not to use notes
• No exams (just projects and papers)
• Open book/notes exams
• Some trust still required!
• Exams focus on problem solving
• Better test of real world situation
• Examples
• Darth Vader has infiltrated your company
  questions
• Barney Fife is your new chief of security
  questions

While auditing Darths computer, you notice that
he is running a program which is generating all
possible different credit card numbers and
encrypting them with the organizations public
key. What would you suspect that Darth is
trying to do?
Barney has invented a new cipher called
quadruple DES, which uses 4 56-bit keys applied
sequentially (much the same way triple DES
applies 3 56-bit keys sequentially). Explain to
Barney why this is not significantly more secure
than triple DES.
15
Suitable Students

• Take class on line because cant come to class
• Full time job during day classes
• Conflict with another class
• Must miss significant part of semester
• Student had to travel overseas for 7 weeks
• No students who can come to regular lecture, but
  dont want to
• Able to make arrangements to come to class once
  or twice
• Must give advance notice and be flexible with
  days
• Example Final research presentation in 5857
• On-line students given choice of 4 possible days
• All were able to come to at least one
• Very computer literate
• Will probably need to do programming assignments
  at home
• Must be able to install and run software with
  little or no help

16
Effects on In-Class Students

• Overall positive effect
• No effect on class attendance
• Most students printed slides beforehand to take
  notes on
• Far more effective than attempting to copy
  complex encryption system diagrams
• Several students used recordings as study guides
• Overall better grades than in previous year

17
Effects on In-Class Students

• Potential negative effect
• Students can become less engaged
• Seems to be more true in undergraduate class
• Effect of detailed slides
• Students less interested in taking notes
• Solutions
• Keep slides entertaining
• Oswald the indecisive orc
• Ask questions
• What games have you personally seen this
  behavior in?
• Worst case Dont post slides until after
  in-class lecture

18
Conclusions

• Asynchronous distance learning can be done at
  little cost
• Web site
• Recording software
• Presentation software
• Requires creativity and hard work
• Very successful results for distance learning
  students
• 4 distance learning students in CSIS 5857 all got
  As
• Distance learning students in CSCI 5895 and 6962
  have done well so far
• Very positive feedback from all distance students
• Changes made to accommodate distance learning has
  benefited all students