The Use of an Electronic Voting System in a Formal Methods Course

Alice Miller and Quintin Cutts

Department of Computing Science

University of Glasgow

MRS4

• Study of reactive, and distributed systems; • concepts of concurrency and communication that arise in such systems; - signalling, - control - associated modelling issues

• focuses on use of SPIN model checker• consists of 20 lectures and ( 10) 1 hr labs

Identified problems with lecture+lab:

•Students unlikely to reflect on practical experience and relate to other formalisms

•Mathematical nature of course does not promote interaction

•Questions viewed as having only one answer

•Students often don’t bother showing up to labs

The solution

• Introduced tutorial-based session using electronic voting system (EVS) to– Encourage participation in lab sessions

prior to tutorial– Affect self-learning via reading of

prescribed text– Promote reflection and an appreciation

that issues not always black and white

EVS: Electronic Voting System

Questions 1-5 are assessed, questions 6-8 are not.1. In SPIN, what can be passed as parameters to

processes? (a) global variables and constants(b) constants and channel names(c) channel names and global variables

Sample questions

based on lab question

80% correct

Encouraged students

4. One of the following statements about the temporal logics CTL and LTL is true. Which is it?(a) CTL is much more expressive(b) the expressiveness of the two logics do not overlap(c) LTL is more suitable for “on the fly” verification

Based on text material

75% correct

CTL not mentioned up to this point in lectures

Could refer to it later on

6. What do you think of the statement ``SPIN allows us to accurately model synchronous communication''(a) the statement is true(b) the statement is false(c) The statement is not exactly true, but it is close enough.

• Lively discussion • Split into buzz groups, asked to

provide examples of synchronous/asynchronous systems

• Generally difficult to decide

7. Some real world examples of protocols (e.g. IEEE 802.11, FireWire, bluetooth device discovery) include some notion of randomness and probability. However Gerard Holzmann does not believe that the addition of probabilities to SPIN is necessary. Do you:(a) agree(b) disagree(c) neither agree nor disagree (i.e. you have a better solution..)

• Half and half• Buzz groups for 5 minutes• 2 advocates chosen, to argue the point• Only a few had heard of prism, seemed

interested

Outcomes

• Reassurance students had read text• Noticeable increase in student

confidence in subsequent lectures• EVS popular

– way to communicate anonymously– Provided immediate feedback

• High level of discussion