Oral presentations

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Oral presentations
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Examples of talks

• Lectures
• Class presentations
• Technical seminars
• Training sessions workshops
• Sermons
• Speeches
• Street preaching
• Discussions in meetings
• Sales pitches

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Characteristics of good/bad talks?

• Address the 4 rhetorical factors
• Start and end on time
• Communicate a few points well
• Include only relevant material
• Use effective graphics

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Checklist for a talk

1. Determine your purpose.
2. Understand your audience.
3. Understand the context.
4. Determine the content.
5. Practice your presentation.

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Determine your purpose
What are some general purposes of presentations?

• To inform
• To tell about a problem or solution, to report
  research results, to educate
• 2. To persuade
• To change attitudes or behaviors, to sell, to get
  something
• 3. To entertain
• To provide enjoyment

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Understand your audience
What are some questions one should answer about
the audience?
What does the audience expect? Who is the
audience? Are they friendly? Hostile? Why might
they want to listen? Is the topic of common
interest? What does the audience know about the
topic? What about topic is most relevant or
interesting? What media are most appropriate? How
long will they want to listen? Can the audience
read? Does the audience crave higher mathematics?
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Understand your audience
Audience retention vs. time
100
75
Retention ()
50
25
0
0
25
50
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Understand the context
What are some questions one should answer about
the context?
What is the occasion? What is the location? What
are room arrangements? What equipment is
required? What equipment is available?
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Determine your content
Keep it simple!!
Focus on a few important points. Motivate the
talk well. Dont show every detail. Leave them
wanting more (and tell them how to get it).
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Organize your content
What are some ways to organize the content?
By topic or flow of ideas By chronology or
time By space (such as for posters/displays) By
classification or categories By problem/solution
By cause/effect
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Practice!
Fill in the blanks or choose the correct answer

• The first version of a talk will likely be too
  ______.
• 2. In 20 minutes, one can practice a 5-minute
  talk _____ times.
• 3. Prof. Rehmann practices the longest/shortest
  talks most.
• 4. The hardest parts of a talk are the ________
  and the _______.
• 5. People who reach the end of the allotted time
  and have discussed only the motivation and
  methods look ________.
• 6. After you practice the talk, dont forget to
  practice ______________.

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Graphics
Identify possible problems in the following
slides and suggest improvements
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• stirring frequency
• d rod size
• N buoyancy frequency

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Objectives
Determine the source of pollution in the Raccoon
River. Model effect of contamination on
downstream waters. Suggest methods to remove
the contamination.
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(No Transcript)
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Summary and Conclusions

• We performed laboratory experiments to determine
  the conditions under which differential diffusion
  occurs and evaluate its effect on the mixing
  efficiency. Diffusively stable profiles of
  temperature and salinity were stirred steadily by
  horizontally oscillating vertical rods. The
  two-component stratification ensures that both
  scalars experience the same stratification and
  forcing, or Richardson and Reynolds numbers.
  Temperature and salinity profiles were obtained
  with a temperature-conductivity probe, and the
  work done by the rods on the water was measured
  with a force transducer. The eddy diffusivities
  KT and KS were estimated by fitting theoretical
  solutions of diffusion equations to the measured
  profiles for temperature and salinity, and the
  mixing efficiency was computed as the ratio of
  the potential energy change during a stirring
  interval to the work done in that interval. The
  average dissipation rate ea was computed from the
  work measurements and an integrated energy
  budget.
• We observed differential diffusion and identified
  conditions for its occurrence. T-S diagrams
  qualitatively show the effects of differential
  diffusion. One can determine whether the
  diffusivity ratio d KS/KT is larger or smaller
  between two cases by comparing T-S diagrams, but
  care must be taken to compare equal time
  intervals made dimensionless by H2/KT.
  Differential diffusion occurred for ea/nN2 lt
  300-500 or for RiT gt 1. The diffusivity ratio
  varied between 0.5 and 1 in the range 50 lt ea/nN2
  lt 500. For similar values of ea/nN2 Barry et al.
  (2001) noted a change in the behavior of the
  turbulence, though they did not have data to
  evaluate Schmidt number effects.
• In the present experiments, eddy diffusivities of
  temperature, salinity, and density collapsed well
  when normalized by the kinematic viscosity for
  large ea/nN2. The data did not collapse as well
  when differential diffusion occurred.
• The experiments also illustrate the effect of
  differential diffusion on the mixing efficiency.
  When differential diffusion occurs, the density
  ratio will be important. If KT gt KS, then the
  mixing efficiency will be greater in cases in
  which more of the stratification is caused by
  temperature. We measured mixing efficiencies for
  cases with low density ratio (Rr 0.25) and high
  density ratio (Rr 5). In both cases, the
  efficiency increased from 0 to 1.5 as the
  Richardson number RiT increased from 0 to 1.
  However, for RiT gt 1, the efficiency for the high
  density ratio case exceeded that for the low
  density ratio case and increased more rapidly.
  The measurements show that effects of
  differential diffusion on the mixing efficiency
  can be significant.

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Methods
We used the following formulas in our
calculations
Single Payment - Compound Amount Formula, (F/P,
i, n) F/P (1 i)n Single Payment - Present
Value (Worth) Formula, (P/F, i, n) P/F (1
i)-n Sinking Fund Formula, (A/F, i, n) A/F i
/ (1 i)n - 1 Capital Recovery Formula, (A/P,
i, n) A/P (i (1 i)n ) / ((1 i)n - 1)
Uniform Series - Compound Amount Formula, (F/A,
i, n) F/A ((1 i)n -1) / i Uniform Series -
Present Worth Formula, (P/A, i, n) P/A ((1
i)n -1) / (i (1 i)n ) where i is the interest
or discount rate (decimal fraction) per
accounting period. n is the number of accounting
periods from 0, there may be several n's. P is a
Present Value at time 0, may be positive or
negative. F is a Future Value at a time n, may
be positive or negative. A is a uniform amount
per period for n periods, may be positive or
negative.
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Results
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Affect of control on zebra mussels
Let 25 gt150 mm pass
Let 100 pass
Let 84 pass
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Cash flows
Year Plan A Plan B Plan C Plan D
0 3,175.36 2,463.04 743.06 4,781.08
1 5,629.08 2,676.00 1,336.62 5,351.27
2 188.67 2,391.24 1,010.07 7,667.57
3 3,564.22 2,215.68 8,941.95 2,849.13
4 8,334.41 7,000.78 7,434.82 5,452.95
5 6,646.24 9,114.28 7,956.42 9,871.16
6 1,542.14 8,109.16 753.14 6,245.39
7 9,851.31 472.14 144.49 4,571.87
8 6,867.51 3,931.02 125.39 4,337.10
9 9,446.77 4,065.59 6,480.05 8,883.56
10 7,408.68 1,226.61 5,267.60 2,807.39
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Net present worth
300
200
Net present worth (K)
100
0
Plan A
Plan B
Plan C
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Source Sisk, Launer, Switky, Ehrlich 1994.
Identifying extinction threats. BioScience
44592-604