advanced topics in distributed systems -...

Advanced Topics in Distributed SystemsPresentations

Guillaume Pierre

Vrije Universiteit

Fall 2010http://www.cs.vu.nl/~gpierre/courses/atds/

Advanced Topics in Distributed Systems Presentations 1 / 41

Table of Contents

1 Presentations should focus on what’s important

2 Presentation structure

3 Visual Stuff

4 Delivering the presentation

5 A few tips for the ATDS presentations


The killer slide

Columbia Shuttle Disaster (2003) was partly due to one bad slideI 7 people died

What happened:I When taking off, some debris was seen to hit one of the wingsI Question: did it damage the wing? Is it safe to re-enter atmosphere?I Study was conducted through mathematical analysis only, based on

test data completely out of range (the actual debris was 640 timesbigger than in the test data)

I Results looked reassuring but Boeing’s engineers were concerned bythe limits of their evaluations

I NASA management only understood the “reassuring” part. . .I The shuttle was allowed to re-enter atmosphere without repairing the

wing


The killer slide


http://www.cs.vu.nl/~gpierre/courses/atds/

11 sentences, 6 levels of hierarchy


Overly reassuring title

“Review of test data” does not refer to the predicted tile damage butto the choice of test models used to predict the damageRemember: this is a mathematical analysis based on very limiteddata


Jargon

SOFI = “Spray On Foam Insulation”


Incomprehensible sentence

You’d better pay attention to the presenter’s speech. . .

But the presentation was also circulated by email


Unclear reference: what is “it”?

Here: “it” = “damage to the protective tiles”

If you miss this, the meaning changes completely


What does “significant” mean?

Here: it means bad

One can interpret this as “statistically significant” (i.e., good)


Weird, inconsistent unit notations

“3cu. In” vs “1920cu in” vs “3 cu in”

Clear version: 1920 in3


The important message is hidden at the end of the slide

And it contradicts the title. . .


An alternative design of the same slide


Another design of the same slide


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3 Visual Stuff



Advanced Topics in Distributed Systems Presentations Presentations should focus on what’s important 15 / 41

What makes a good presentation?

You fully understand the content you are presenting

You present this content is a synthetic way

You avoid a number of classical pitfalls

Most difficult part: being synthetic!

The three keywords are: structure, structure, structure.


Observation

A presentation at a conference is usually limited to 20 minutes

The paper you come to present is about 10-15 pages of textI You already had to fight to make everything fit within these limits

Axiom

It is impossible to explain everything within these 20 minutes!

Even if you speak very fast. . .

You will have to select only what is important and skip all the rest


Two minutes per slide

In general, plan to spend about 2 minutes per slideI Some slides take a bit less, but not that much

A conference-style presentation will contain roughly 10–12 slides

Each slide will contain 10–12 lines at mostI Some authors make stricter recommendations: 6 lines, 6 words/lineI But beware of messages that are so compressed that they become

incomprehensible


Focus only on what’s important

What is important in a technical presentation?I Most important: what is the problem you are trying to solve?I And also: a glimpse at your solutionI All the rest does not matter! (almost. . . )

People can always read the paper afterwardsI You can skip entire aspects of your workI Just mention them: “you will find more information in the paper”


Avoid complicated abstractions

In a paper you present your work in the most general caseI You end up writing text at a high level of abstraction

In a presentation, make things concreteI No need to present the full generality and all the 512 special cases

discussed in the paperI Do not copy-paste this impressive 5-lines-long math formula from the

paper!I Present only the normal/interesting caseI Maybe: present just one running example that illustrates your message


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Advanced Topics in Distributed Systems Presentations Presentation structure 21 / 41

General presentation structure

1 Title

2 Problem

3 First glance at the solution

4 Structure of the talk

5 . . .

6 . . .

7 . . .

8 Conclusion

9 Take-home message


The right content of slide 2

The first slide is easy: title, author name, logo of the organization,etc.

What about the second slide?I Most people present the structure of their talk. WRONG!I The audience has barely read your title, and has no idea what the talk

is aboutF “I will first introduce the problem, then show my solution, then there

will be some performance evaluation, and then I will conclude.” Thesame applies to every presentation!

F “I will introduce isomorphic para-spaces. Then I will show that thetheorem of XXX proves the non-linar nature of that space, thanks tothe use of results from YYY.” Nobody understands anything!


The right content of the first slides

Better start with the problem (slide 2)I What is the problem you are trying to solve?I Why should the audience pay attention to your presentation

instead of cheking their email?I Make the problem extremely concrete (e.g., Columbia shuttle disaster)

Then give a hint of what the solution looks like (slide 3)I Just enough so that the audience can start guessing what your talk is

going to contain

Then the structure of the talk (slide 4)I They will now understand why you want to apply XXX’s theorem, and

what it was about in the first place

Isn’t this a familiar structure?

This is a stripped-down version of the structure of a paper introduction


The last slide

After your presentation the audience will ask questionsI The last slide of your presentation will remain displayed for several

minutesI How useful is it to display Any question? during 10 minutes?

Use the last slide to repeat the take-home messageI If I remember only one idea from your presentation, what should this

idea be?

Example: what is the take-home message of this presentation?

When preparing a presentation,focus on the essential message

and skip all the rest


Backup slides

You can often anticipate the questions that the audience may askI Elements that you decided to skip in your presentationI Questions asked by the reviewers of your paperI Questions asked by audiences in a previous presentation

Prepare 1 slide to answer each such question!I Performance graphsI State of the artI Tricky/controversial aspects of your work

Show your backup slides only if the audience asks the questions youprepared

I And take a note of the questions you receive so that you can preparebackup slides for the next time. . .


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Advanced Topics in Distributed Systems Presentations Visual Stuff 27 / 41

Font size

Use large enough fonts! No more than 12 lines of text per slideI Print one slide in A4 format (the one with the smallest fonts)I Put the slide on the floor, stand on a chair above itI You should be able to read everything easily!

Note: the same holds for figure legends etc.I What’s the point including them if the audience cannot read?


Short sentences only!


Beamers have real bad contrast

A typical LCD screen has a contrast of 2000/1, while a typicalbeamer has a contrast of 500/1 (in perfect conditions)

I With background light you get maybe a contrast of 100/1 or 50/1I Your figure with 5 different shades of purple looks nice on screen but

nobody will see anything using a beamer!

Use only strong high-contrast colors (black, blue, red, brown)I Avoid lighter colors: yellow, pink, greenI Do not mix red with green: 7-10% of male population is colorblind!I Beware of background colors: white works best


Contrast


Avoid jokes and funny cartoons

Your only goal is to convey as much information as possible during ashort period of time

I Remember? You had to strip your presentation to the strictly essentialmessage

I Every written/spoken word counts

Do not distract the audience with funny cartoons and jokes!I All the time that people read the cartoon they don’t listen to you, and

lose track of the presentationI It also conveys a negative message: “I know that this presentation is

totally boring. I hate it myself as well. Instead, let me try to entertainyou during this painful moment.”

Similarly: sophisticated slide transitions distract the audience,especially if you use different ones each time

I “What will the next transition be?”I Reserve these effects to emphasize one important message per

presentation


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Advanced Topics in Distributed Systems Presentations Delivering the presentation 33 / 41

Delivering the presentation

Watch the audienceI Do not watch the screen nor your laptop

Speak loudly enough so the audience can hear youI Trick: select somebody at the last row and talk to that person

Give the audience enough time to think before you change topicsI Just stay silent for 5 seconds before moving on to something else

Do not read your slides aloudI What’s the point? The audience can read your slidesI Make new sentences during the presentation

Emphasize what’s importantI Do not use monotonic voice!

Do not play strip-tease with your slides. . .I “You can’t be trusted to listen to me if I show you the next line too”


Know your presentation by heart!

You should know by heart which slide contains what informationI . . . and in which orderI You should never get lost!I What was already discussed, what will come next

But do not learn the text of your speech by heart!I ⇒ Mechanical deliveryI Better to make new sentences on the spot


Practice your talk

Practice your talk beforehand!I If possible with a couple of friends to listen to youI Did they understand what the take-home message is?I Did you emphasize what is important?I Is your talk well structured?

Beware of time limitsI If your talk is too long, speaking faster will not help

F You will have to cut on the content

I If you run overtime during the real presentation:F Skip slides, focus on the most important stuffF In extreme cases: skip everything, move directly to conclusion


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Advanced Topics in Distributed Systems Presentations A few tips for the ATDS presentations 37 / 41

Special tips for ATDS presentations

ATDS presentations must discuss three papers, not one!

You have 25 minutes for the presentation (excluding questions)

You must give one presentation, not three!

Tip #1: Spend enough time in Introduction

The introduction is extremely importantI What is the presentation about? What is the problem we are going to

address?I Why is this an interesting topic?I Understand the problem better (without telling about solutions)I Which structure does your presentation follow?

Plan to spend 25-30% of your time in introduction



Tip #2: Select your secondary papers carefully

Your presentation must tell a single storyI Oppose and contrast three different approaches to the same problemI Present complementary techniques that address different aspects of

the same problemI Show techniques which improve on each otherI Etc.

If you don’t find the right secondary papers, search for better onesI For example papers that cite or are cited by your primary paper (check

http://scholar.google.com)I Feel free to propose other choices of secondary papers. . .



Tip #3: Think carefully about the structure of your presentation

Structure, structure, structure

Let the audience know how your three papers fit together

Remember: 1/3 of the audience has not read the primary paper!

Possible structures:I Simple: Intro, paper 1, paper 2, paper 3, conclusion.

F Explain how these three papers relate to each otherF In which order will you present the three papers?

I More sophisticated: synthetic presentationF Structure like a lecture: cover different aspects of the problem in a

logical orderF Use information from each paper where it fits

I If you oppose three approaches to the same problem: present/opposeall three papers simultaneously

Be creative!


http://scholar.google.com

References

“Any recommendations for an oral presentation that must beprepared in a hurry?” Jean-Luc Doumont, IEEE PCS Newsletter 51:9(Oct 2007). http://www.principiae.be/papers.html


http://www.principiae.be/papers.html

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