Comp 620: Seminar in Secure Systems
Student Paper Presentations
(adapted from the Comp 520 presentation advice)
One of the main goals of this course - besides
learning about secure systems - is to teach
you to give good talks.
You will present a paper in front of the class,
in the hope that this experience will prepare you for giving
talks at conferences, interview talks, etc.
At the end of the semester,
you will also present the results of your group's
project to the class.
You should realize that giving a good lecture is hard work
and requires extensive preparation.
Do not underestimate the amount of time this preparation takes.
The following set of recommendations has been distilled from
more than five years of experience with this course format,
with some additional input from other sources.
The same problems occur time and again, and this is an attempt
to address some of them ahead of time.
Not all recommendations apply equally to all papers
and to all speakers, but they provide some guidance in
paper presentation that hopefully you will find valuable.
If this is the first time you are giving a technical talk,
you will not be able to follow all these recommendations at once.
Like with many other things, with talks, practice makes perfect.
In order to distinguish the more from the less important,
a number of recommendations have been formulated as rules.
Try to pay particular attention to these rules in preparing
and giving your talk.
As two heads are usually better than one, a second student
will be assigned to each paper to help the presenter digest
the paper and prepare for the presentation.
Understanding the Paper
The essential ingredient for a good paper presentation is that
you thoroughly understand the paper and the points it is trying
Nice slides and a polished presentation are important,
but cannot make up for a lack of understanding.
Therefore, I suggest that you spend a significant amount
of time trying to grasp the contents of the paper you
This may require reading additional papers as well, to get
a better understanding of the context.
In particular, I expect you to read at least all the other
class papers on the same topic.
While it is important to understand the technical details
in the paper, the primary goal in this first phase of the
preparation is to understand what the key points
are that the paper is trying to make.
What the key points are is a question
you should evaluate in the context of the audience
for which you are presenting the paper.
Your paper presentation here is part of
a course about software for distributed systems.
A particular paper that we read may contain an interesting
hardware discussion, but, unless that discussion is
essential in understanding the software concepts presented
in the paper, it is probably not a key point as far as this
course is concerned.
Also, do not forget that it is a course, and that therefore
for many people your presentation is their first exposure
to the material.
This implies that relatively high-level points are probably
of more interest, while low-level details are most likely
going to be lost on your audience.
Your choice of what topics to cover might be different if
you were to present the paper at a conference or as a
job interview talk.
Adapting the Paper for Presentation
that the amount of information that people
carry away from a lecture or a presentation is relatively small.
Therefore, it is essential that you very specifically highlight
the key points of the paper.
People are most likely to forget the rest anyways.
It is also well-known that the audience is most attentive
in the beginning of a lecture.
Attention then drops until the point where the speaker signals
that the end of the talk is near, at which point attention levels
The most common problem with student presentations in previous
versions of Comp 620 has been that the student goes over the paper
from A to Z, in the same order as the written paper, without
adding or deleting anything.
This is a very bad idea.
A written paper is an archival document, and therefore
it tries to be complete.
With an oral presentation, one tries to relate the key points
of a paper to the audience.
That requires highlighting those key points, and only briefly
summarizing or deleting lesser points.
- Rule 1
You should have a slide very early on that states the key points
of the paper, and nothing else.
You should have a similar slide at the end.
You should decide on these slides first before you proceed.
Often people are not quite sure what the key points are, or
they cannot make up their mind.
They then try to bury the slide with the key points into
an ``overview'' slide that outlines the paper or the talk.
This is not acceptable.
Having an overview slide may be a good idea, but it is
never a substitute for a slide with the key points
of the presentation.
Once you have gotten past this part, it is now time to
develop the rest of your presentation.
If, for instance, the paper claims to provide some
functionality not provided by earlier systems, you
should specifically state what this functionality is,
what it is good for, how it is accomplished, perhaps
what the costs are, etc.
If the paper does something better or faster than other
systems, you should explain what the new concepts are that
allow it to do so, and quantify the improvement.
Throughout your discussion, you should occasionally
return to the key points to make sure that the audience
does not lose sight of the overall context.
- Rule 2
The rest of the talk should be structured such that it
elaborates and clarifies the key points.
People are often tempted to budget time to various
parts of the talk in a way proportional to the amount
of time they spent getting to understand the corresponding
part of the paper.
This is often a bad idea, because it may lead to a
disproportionate amount of time being spent on tricky
details that do not contribute to the overall goal of
getting your audience to appreciate the paper.
Tricky details are far better understood by reading the
Your talk should be sufficiently motivating such that
people actually want to go read the paper to figure out
If you do decide to go into some complicated aspect of
the paper, and again, you should only do so if you consider
it essential, you have to explain it in real detail
and budget enough time to give the audience a chance
to absorb the level of detail.
There is a big danger here of starting to explain some
complicated aspect of the paper and
try to hurry through it because it is not very important.
Of course, nobody understands what you are trying to do.
Attempts like this usually end with the comment
``Well, I know it's complicated, I don't have the time
to explain it all in detail, but I hope you got the idea''.
Congratulations, you just confused everybody.
Many of the papers that we will read in this course have
experiments, measurements, and performance results in them,
``numbers'' as the theoreticians say.
In other words, you should make sure that it does not come
across as ``a bunch of numbers'' but as the account of a
There is nothing worse than throwing up a slide with some numbers
on, and leave it at that.
Even if the numbers are digested into a table or a graph,
that does not relieve you of the responsibility to explain
how these results were obtained, what they mean, etc.
More will be said about the slides used for presenting
experimental results below.
You should make sure that you budget enough time for
this part of your talk, as it is a frequent source
of questions from the audience.
- Rule 3
You should fully explain the purpose of the experiments,
the experimental setup, the results, and the conclusions
to be drawn from these results.
A paper presentation in this course is different from a
presentation at a conference, in that you are presenting
somebody else's work and you may not agree with all of it.
Avoid confusion between the paper itself and
your opinion of it.
The emphasis in the evaluation should be on the contents
of the paper and also, but to
a lesser extent, on the paper's overall structure and presentation.
This is also a good place to make connections with other papers
we have read and cast the paper at hand into a wider context.
- Rule 4
Your talk should consist of two clearly delineated parts,
one in which you present the paper as if you were the
author, and a second one in which you offer an evaluation
of the paper.
You should allow for approximately 45 minutes of presentation.
This is just a guideline, not a strict upper or lower limit.
In any case, you should allow for questions both during and after
the talk, and also for some discussion after the talk.
A good rule of thumb is to have about one slide per
two minutes of talk, although this is certainly
not an universal rule.
If you put something on a slide, it must be that you think
it is worthwhile for the audience to read it.
From this follows the cardinal rule for making slides,
unfortunately also the rule that is most often sinned against.
I cannot stress this rule enough, so just to make sure,
I will repeat it.
- Rule 5
Use a big letter size.
There is an important corollary to this rule.
Occasionally you want to use a figure (or a table) from the paper.
You should not do this by copying the figure on to
a slide, but by redrawing it on a size that will
be readable by your audience.
In particular, units on graphs or in tables should be clearly
If there is too much in a particular graph in the paper,
split it up in two graphs or present only part of it.
- Rule 6
Use a big letter size or else ...
The second rule is almost equally obvious, but also
First, you should leave large margins, both vertical and horizontal.
Be especially careful not to go too close to the bottom
of the slide, as the audience may not be able to see
the bottom of the screen.
If you find yourself shifting the slide up and down during
your talk, then your margins are not large enough.
your slides should just contain the bare essentials:
no full sentences, just a few keywords.
Never try to cram a lot of material on to a single side,
use two or more slides instead.
There is nothing wrong with a slide that is three quarters empty.
- Rule 7
Do not clutter your slides.
A picture is almost always better than text.
Long bulleted lists are boring.
Try to distinguish major and minor points by using
indentation, by using boldface, etc.
It is a big plus if you do so consistently throughout
Colors can be very appealing but must be used with care.
You must be consistent.
If you have two slides with horizontal lines depicting
the execution of processes and arrows representing messages
between them, use the same color on both slides for
the processes and the same color for the messages.
Over-use of color can however be distracting.
You must also be careful with certain colors.
Red and pink are indistinguishable with many projectors.
- Rule 8
Your slides should be visually appealing.
All slides should have a title that describes this concept.
If the explanation of a concept goes on for more than one
slide, then repeat the title with some qualifier, or with
just (Continued) added to a title.
Never start a new idea in the middle of a slide, or try
to convey more than one concept in a single side.
Use a new slide instead.
As said before, there is nothing wrong with a slide that
is three quarters empty.
It is almost always a bad idea to cover up part of a slide,
because it almost always means that you put too much on the slide.
Besides, half of the time, the piece of paper that you are
using to cover up part of the slide falls off.
In the same vein, while overlays can be used to advantage,
it is often better to put up a completely new slide,
which may include most of what was on the previous slide.
Overlays are difficult to line up correctly, and slides
taped together tend to fall of the projector.
Overlays of more than two or three slides do not project
- Rule 9
A single slide should never try to convey more than a single concept.
If you know ahead of time that you are going to use a
slide more than once, you should make as many copies of
the slide as you will need and insert them at the appropriate
place in your stack of slides.
This avoids searching through the slides during the talk.
There is some debate as to whether it is better to typeset slides or
to write them by hand. Rumor has it that at theory conferences
handwritten slides are the norm. At systems conferences this would be
considered very sloppy. You should use Latex or Powerpoint to prepare
your slides. Both have reasonably good facilities for doing so. I
recommend against handing out copies of your slides before the talk,
because it reduces interaction between the speaker and the audience.
Make your slides available from your home page, either in Postscript,
PDF, or HTML format, so that other students can refer to your slides
So now you have all your slides ready.
Get some people together, preferably in the room where you
are giving the talk, and go through the entire talk, as
if you were giving it in class.
Ask somebody to time it, and ask people to make notes.
It is also a good idea to videotape the talk.
We have a video camera available, and you are encouraged
to take advantage of this facility.
Some people also find it useful to give the talk in an
empty room with just the video camera running.
The first time you give a talk, you will be surprised to find out that a
lot of people will look at you with completely empty faces.
Some people will fall asleep.
An empty room with a video camera running will prepare
you for this situation.
You can reserve the video camera with the secretary.
When not reserved, it is available on first-come-first-served basis.
- Rule 10
You should do (at least) a couple of dry runs.
You will find that after a first dry-run, you will want to change
In fact, it is not uncommon for people to change all
of their slides after a first dry-run.
For a first dry run, you might just have some of the
slides hand-written or hand-drawn, as long as they
accurately reflect what you are going to have on them
for the real talk.
- Rule 11
Avoid premature optimization. Get the contents right
first, and then make your slides look pretty.
After you have your talk ready, you should spend some
time trying to anticipate what questions you might get
during and after the talk.
If the answer to a particular question you expect is difficult,
prepare a slide with the answer.
In general, take a few extra blank slides and a suitable pen
with you to the
talk, so that you can write something down if you need to.
One final rule.
The night before your talk is not the right time to do
all of the above.
Sleepwalkers do not make for exciting speakers.
- Rule 12
Get some sleep the night before your talk.
To Memorize or not to Memorize?
There is often debate on how much of the talk you should
Your presentation should be smooth, but at the same
time it should not appear completely scripted.
How much of the talk you have to memorize to
accomplish this effect differs from person to person.
You should definitely not have to consult your notes
on a regular basis.
Ideally, you should not have to do so at all.
It is very useful to completely memorize the first
minute of your talk.
Many people are quite nervous in the beginning, and
memorizing the first minute
helps them get off to a smooth start.
Along the same lines, you should outline in detail
what you are going to say in
the technically complicated parts of the talk, if any.
Only the most accomplished speakers are capable of
improvizing successfully at such times.
You Are on the Stage
Audiences are far more forgiving if they think you are
If you look scared or uncertain, it is like letting the
wolves smell blood.
Show some enthusiasm for the subject.
Speak loud and forcefully. Do not end your sentences in a mutter.
Do not be afraid to raise and lower your voice, to
delineate more or less important points.
A moment of silence at the right time can do wonders.
If you just said something important or something
let it sink in for a while before you continue.
This technique will work particularly well if your
slides are such that each slide introduces a new concept.
Do not talk while you are changing slides, and give the
audience time to absorb what was on the previous slide.
- Rule 13
Make it look like you are having a good time.
Do not stand in front of it, and do not block the projection
of the slide on to the screen.
Especially after changing slides, people tend to continue
to stand right next to the projector.
In a level classroom, you should go stand next to
the screen after changing slides.
Some speakers also move around while they are talking,
a good idea when done in moderation.
Also, never remove a slide before people have had a
reasonable amount of time to read what is on the slide.
Never flip back and forth between two or more slides.
- Rule 14
Make sure that the audience can always see the screen.
Make sure you have a pointer with you to point things
out on the slide.
Pointing things out with a pen or with your hands obscures
the projection of the slide.
Do not play with the pointer; put it down when you do not need it.
It is a matter of argument whether you should point on the
projector or on the screen.
Either way can be done right, but pointing to the screen is
often better (not always possible, though).
If you point on the projector, make sure that you are not
obstructing the projection or the view of a large part of the
audience, especially the part of the audience sitting on
the same side of the projector as where you are standing.
If you point on the screen, make sure that you turn back to the
Do not stand or talk for an extended period with your back towards
Avoid having to write on a slide during the talk,
but have an appropriate pen with you just in case.
You will certainly obstruct the projection while you are
Make sure to step back and take a short pause afterwards
so that the audience can see what you have written before
Most people are not very funny, anyways, especially when
they are nervous.
There is nothing more awkward than somebody who is not
funny and who is trying to be.
There is nothing more likely to throw you off than to
have the audience react stonecold after you tried to make a joke.
In general, if something goes wrong during the talk
- most likely something will in fact go wrong -
do not let it throw you off.
Also, people might not take you seriously if your
talk turns into a stand-up comic act.
This does not mean that you should not be able to see
the humor of the situation if something funny happens.
But just let it happen, do not try to make it happen.
When it does happen and people start laughing, wait
until the laughter dies out or nobody will have heard
what you said.
Also, in some situations you will be introduced before the talk,
for instance for an interview talk.
Some people have the extremely annoying habit of introducing
the speaker by telling some supposedly funny story (In
some departments this is a tradition).
This is really great, because it guarantees that nobody
is listening right from the beginning.
If this happens to you, make absolutely sure to wait until
the laughter dies out, and be very serious during the
first few minutes of your talk to get things back on track.
- Rule 15
Do not try too hard to be funny.
Interacting with the Audience
Do not look at the screen, at your notes, at the slide
projector, or away from the audience in any other way.
Look at the whole audience, not just your friends, the instructor,
the first row.
You are much more likely to keep the attention of the
audience going this way.
- Rule 16
Look at the audience and seek eye contact with them.
If you are really confident, you should try to engage your
audience in actively participating through questions and answers.
If you ask a question, you have to be willing to wait until
somebody volunteers an answer.
If you don't, your question will come across as perfunctory,
and you will certainly not get any answers the second time
As said before, you have to be pretty confident to pull this off.
An important aspect of giving a talk is dealing with questions.
The first thing you should realize here is that questions are
a good thing.
It means that people are listening.
It does not (necessarily) mean that you did a poor job
of explaining something.
So maintain a positive attitude to questions and the people
who are asking them.
Allow the person who is asking a question to finish his
Quite often, speakers jump in halfway with their response.
It is rude to do so.
And you are probably answering the wrong question.
It makes people feel good if you ask them if they understood
It is also perfectly acceptable to say that you do not know
Do not try to hide this by not answering the question, and certainly
not by making fun of the question or the questioner.
The above not withstanding, it is true
that many audiences have a self-appointed designated jerk.
Every audience also has people who do not understand a word
of what you are talking about.
The combination of the two, a person who repeatedly asks
stupid questions on a tone of ``what the hell are you
talking about'' can be quite deadly.
This is one of the most difficult situations to deal with,
and there is no universal approach to combat the problem.
You are lucky if the audience contains a jerk exterminator.
This is the person from the audience who casts an annoyed
look over his shoulder, and gives a one-word answer to the question.
If that happens, you are safe. Do not rub it in.
If not, you must be very
firm in not letting this person derail your talk, while
remaining polite (if at all possible).
One approach is to ask the jerk to defer his questions until
after the talk.
If he keeps on asking questions, start giving one line answers,
and continue immediately without checking if he understood
This situation is unlikely to occur in a course, but in general
you should be prepared for it.
The Role of the Instructor
Speakers and the person who helps them prepare their talk
should come and see me at any time prior to the talk.
Speaking from experience, there seem to be two times at
which a meeting is extremely helpful: (1) after you have digested
the paper to check if you figured out what the main points are
and to clear up technical details about the paper;
(2) after you have done a dry-run and fixed up your slides
according to the comments of the people who attended.
I will go over your slides with you and point out possible
At lecture time, I will introduce you, and
I will lead the discussion after your talk, but
you should not count on me helping you out during the talk.
Although I may say or ask something, you are in charge
and you should be able to handle whatever situation comes up.
After each talk I will hand out evaluation sheets, on which
everyone will be asked
to evaluate the presentation.
I will then summarize the student evaluations, add my own comments,
and provide a summary to the speaker.
Your evaluations will have no effect on the speaker's grade, so I urge
you to be candid and constructive.
Your evaluations may however affect your grade,
so I encourage you to take them seriously.
I will also videotape all student presentations.
The tape will be available for
some amount of time after the presentation.
If you want to keep the tape for an extended amount of time,
you should bring your own tape.
The intent of these presentations
is not only that you learn the material in
each paper, but that you also learn how to make good presentations.
These evaluations will allow you to get feedback on how the audience reacts
to and perceives your presentation,
and the videotape will allow you to see yourself as the audience sees you.
Most people seem to have an incredible fear of seeing themselves.
It's usually not that terrible.
And everybody who has brought up the courage to examine the tape in detail
has found it to be extremely helpful.
You should understand that the fact that a paper is presented
by a student may occasionally take its toll on the material.
The discussions after the paper presentations and the review
lectures are meant to smooth out such problems, but they are
not a perfect remedy.
This is the price that you have to be willing to pay
for the opportunity to practice speaking in public.
Last modified: Tue Apr 13 00:37:44 CDT 1999