1
00:00:00,000 --> 00:00:00,688

2
00:00:00,688 --> 00:00:03,562
[MUSIC - RANDY ROGERS BAND, "TONIGHT'S
 NOT THE NIGHT (FOR GOODBYE)"]

3
00:00:03,562 --> 00:00:21,589

4
00:00:21,589 --> 00:00:22,630
DAVID MALAN: Hello world.

5
00:00:22,630 --> 00:00:26,430
This is CS50 Live and
this is our season finale.

6
00:00:26,430 --> 00:00:28,620
But boy do we have a good
episode for you today,

7
00:00:28,620 --> 00:00:32,990
in particular, the latest in
image stabilization, robo soccer,

8
00:00:32,990 --> 00:00:36,410
and ultimately, a look
back at CS50 Live itself.

9
00:00:36,410 --> 00:00:39,600
Now you may recall that desk lamps
have been a bit of a thing this year.

10
00:00:39,600 --> 00:00:43,060
In fact, this was kind of a spontaneous
introduction to CS50's week zero

11
00:00:43,060 --> 00:00:44,940
this past fall 2013.

12
00:00:44,940 --> 00:00:47,730
>> Just a day or so before the very
first lecture this past fall,

13
00:00:47,730 --> 00:00:51,250
I decided it would be kind of fun to
be able to visualize binary-- zeros

14
00:00:51,250 --> 00:00:54,300
and ones-- and so I headed to
CS50's favorite store, Target,

15
00:00:54,300 --> 00:00:56,090
and picked up these desk lamps here.

16
00:00:56,090 --> 00:00:58,890
Now, at the end of the lecture,
I found that I didn't really

17
00:00:58,890 --> 00:01:00,460
need these lamps for another year.

18
00:01:00,460 --> 00:01:03,710
And even if I did, it would
kind of be an old bit by 2014,

19
00:01:03,710 --> 00:01:05,940
so I offered them up to
students in the audience.

20
00:01:05,940 --> 00:01:09,620
>> Now, since then of course, we've been
receiving quite a few emails, Facebook

21
00:01:09,620 --> 00:01:14,750
posts, and tweets requesting these same
CS50 desk lamps to be sent nationally

22
00:01:14,750 --> 00:01:15,960
and internationally.

23
00:01:15,960 --> 00:01:17,100
And so we did.

24
00:01:17,100 --> 00:01:20,870
And we got back this very nice
note from CS50's Luigi Morelli

25
00:01:20,870 --> 00:01:23,000
in Rome, Italy who wrote us this.

26
00:01:23,000 --> 00:01:23,940
"And here I am!

27
00:01:23,940 --> 00:01:25,530
Thanks to CS50 staff.

28
00:01:25,530 --> 00:01:27,930
Hey, look at those
four books behind me."

29
00:01:27,930 --> 00:01:31,590
>> In fact, if you do look up there on
the top shelf, you will see four books.

30
00:01:31,590 --> 00:01:35,850
And if we enhance, you'll see that it's
a canonical set of computer science

31
00:01:35,850 --> 00:01:38,030
books by a very renowned
computer scientist known

32
00:01:38,030 --> 00:01:41,100
as Donald Knuth who wrote,
The Art of Programming.

33
00:01:41,100 --> 00:01:44,870
So if you yourself were looking to build
your own collection of computer science

34
00:01:44,870 --> 00:01:48,780
canon, go ahead and take a
look at The Art of Programming.

35
00:01:48,780 --> 00:01:52,580
>> Now, meanwhile, if we take a look at
videos that some of your classmates

36
00:01:52,580 --> 00:01:56,680
have submitted, we will see the
first one from Rian from India.

37
00:01:56,680 --> 00:01:57,180
Hi.

38
00:01:57,180 --> 00:01:59,105
I'm Rian [INAUDIBLE] from India.

39
00:01:59,105 --> 00:02:01,940
And I'm taking CS50 online [INAUDIBLE].

40
00:02:01,940 --> 00:02:04,410
And the reason I want
the lamp is basically

41
00:02:04,410 --> 00:02:06,910
because I don't have a
lamp at all and I really

42
00:02:06,910 --> 00:02:10,519
need one as I'm doing [INAUDIBLE]
for [INAUDIBLE] and all this stuff.

43
00:02:10,519 --> 00:02:14,400
And I don't have a desk
lamp or anything like that.

44
00:02:14,400 --> 00:02:17,000
So it would be really great
if you guys would send me one.

45
00:02:17,000 --> 00:02:20,750
I'm Rian [INAUDIBLE], and this is CS50.

46
00:02:20,750 --> 00:02:22,750
DAVID MALAN: Now, your
next classmate, Mauricio,

47
00:02:22,750 --> 00:02:24,590
you may recall from a previous video.

48
00:02:24,590 --> 00:02:27,230
But this time, Mauricio
decided to take it up a notch

49
00:02:27,230 --> 00:02:30,580
and actually deliver his
own lecture for week zero.

50
00:02:30,580 --> 00:02:34,324

51
00:02:34,324 --> 00:02:37,090
>> MAURICIO RADA: So this is CS50.

52
00:02:37,090 --> 00:02:42,050
My name is Mauricio Rada, and
73% have no prior experience

53
00:02:42,050 --> 00:02:46,300
in computer science, contrary
to what you might think.

54
00:02:46,300 --> 00:02:50,120
So today, we thought we would chip
away at that lack of familiarity,

55
00:02:50,120 --> 00:02:54,920
but also give you a sense of, for
those of you with more comfort, which

56
00:02:54,920 --> 00:02:57,420
directions you can go this semester.

57
00:02:57,420 --> 00:02:58,860
>> So let us start with this.

58
00:02:58,860 --> 00:03:03,572
I have these little desk
lamps here, so-- oh.

59
00:03:03,572 --> 00:03:05,280
We haven't any desk lamp here.

60
00:03:05,280 --> 00:03:06,470
We can't go on.

61
00:03:06,470 --> 00:03:09,250
So you will have to end this lab here.

62
00:03:09,250 --> 00:03:13,500
This is not CS50.

63
00:03:13,500 --> 00:03:14,560
>> At the next CS50--

64
00:03:14,560 --> 00:03:17,680

65
00:03:17,680 --> 00:03:20,170
>> DAVID MALAN: And lastly,
is Sid, also from India,

66
00:03:20,170 --> 00:03:24,800
who actually decided to
create for us his own song.

67
00:03:24,800 --> 00:03:28,790
>> SID: Hi, I'm Sid, and I'm from India.

68
00:03:28,790 --> 00:03:32,980
I want a desk lamp because--
how about I put it this way.

69
00:03:32,980 --> 00:03:38,348

70
00:03:38,348 --> 00:03:41,276
>> [MUSIC PLAYING]

71
00:03:41,276 --> 00:03:48,620

72
00:03:48,620 --> 00:03:58,175
>> It's kind of funny how life can change
once you take CS50 in a matter of days.

73
00:03:58,175 --> 00:04:02,320
So I'm making this
video to show you guys

74
00:04:02,320 --> 00:04:06,110
why I deserve a brand new desk lamp.

75
00:04:06,110 --> 00:04:08,850
So it goes like this.

76
00:04:08,850 --> 00:04:13,190
I get yelled at every night for
not switching off the lights.

77
00:04:13,190 --> 00:04:15,773

78
00:04:15,773 --> 00:04:17,314
SPEAKER 2: Switch off the light, man!

79
00:04:17,314 --> 00:04:19,170
SID: Just a second.

80
00:04:19,170 --> 00:04:24,574
Whether I'm writing lyrics
or coding some [INAUDIBLE].

81
00:04:24,574 --> 00:04:26,490
SPEAKER 2: Dude, I'm
switching off the lights.

82
00:04:26,490 --> 00:04:27,850
SID: Five minutes.

83
00:04:27,850 --> 00:04:29,580
Just five minutes.

84
00:04:29,580 --> 00:04:32,250
One love for CS50.

85
00:04:32,250 --> 00:04:35,080
One love for the desk lamps.

86
00:04:35,080 --> 00:04:35,846
One love.

87
00:04:35,846 --> 00:04:39,600
If I don't get one, I won't survive.

88
00:04:39,600 --> 00:04:42,500
So please give me a desk lamp.

89
00:04:42,500 --> 00:04:44,680
Darkness makes me wet my pants.

90
00:04:44,680 --> 00:04:47,730
Please give me a desk lamp.

91
00:04:47,730 --> 00:04:49,260
Desk lamp is all I need.

92
00:04:49,260 --> 00:04:57,470

93
00:04:57,470 --> 00:04:59,177
I hope you like it.

94
00:04:59,177 --> 00:05:01,260
DAVID MALAN: Now lest I
be shamed on the internet,

95
00:05:01,260 --> 00:05:04,880
it's CS50 that's an introduction to the
intellectual enterprises of computer

96
00:05:04,880 --> 00:05:06,710
science and the art of programming.

97
00:05:06,710 --> 00:05:09,610
But Professor Donald Knuth's
books, if you would like to Google

98
00:05:09,610 --> 00:05:13,280
and find them yourself, are The
Art of Computer Programming.

99
00:05:13,280 --> 00:05:17,090
>> Now, you may recall that CS50 recently
participated in this, a 48 hour film

100
00:05:17,090 --> 00:05:19,950
project wherein CS50 had
just 48 hours to create

101
00:05:19,950 --> 00:05:22,580
a short film with a
few required elements.

102
00:05:22,580 --> 00:05:25,560
Now, one of the scenes from
that film was this one here

103
00:05:25,560 --> 00:05:27,570
wherein Daven was
desperately running along

104
00:05:27,570 --> 00:05:31,540
the Charles River near Harvard
trying to just say hello.

105
00:05:31,540 --> 00:05:34,710
Now, what you might not have realized
is that running in front of these two

106
00:05:34,710 --> 00:05:36,170
were actually three guys.

107
00:05:36,170 --> 00:05:38,460
In fact, pictured here
is some of CS50's team.

108
00:05:38,460 --> 00:05:42,600
And if we zoom in, you'll see Ian
holding the camera, Patrick holding

109
00:05:42,600 --> 00:05:44,880
Ian, and Dan directing the scene.

110
00:05:44,880 --> 00:05:48,330
>> Now, in fairness, if we zoom
out, you'll see CS50's own Ramon

111
00:05:48,330 --> 00:05:50,490
Galvan who was just running.

112
00:05:50,490 --> 00:05:52,610
Now, what Ian was
holding with the camera

113
00:05:52,610 --> 00:05:54,560
was this device here
which performs something

114
00:05:54,560 --> 00:05:58,160
called image stabilization which is the
technology with which we were keeping

115
00:05:58,160 --> 00:06:01,930
that shot along the river so relatively
steady even though those guys were

116
00:06:01,930 --> 00:06:03,290
all running backwards.

117
00:06:03,290 --> 00:06:06,852
Now, you might know of this kind
of technology from yesteryear.

118
00:06:06,852 --> 00:06:08,810
In fact, if you grew up
with the so-called gyro

119
00:06:08,810 --> 00:06:11,130
bowl, which looked a little
something like this, this

120
00:06:11,130 --> 00:06:15,160
is a very simple device that
essentially spins on three axes

121
00:06:15,160 --> 00:06:18,310
so that you have some cereal
inside of this bowl, in theory,

122
00:06:18,310 --> 00:06:20,830
it should never fall out
because the handles will always

123
00:06:20,830 --> 00:06:23,570
keep the bowl itself
in an upright position.

124
00:06:23,570 --> 00:06:25,570
Now, I recently had an
opportunity to spend time

125
00:06:25,570 --> 00:06:29,600
with CS50's own Dan Coffey, who went
into more technical detail as to how

126
00:06:29,600 --> 00:06:34,040
more modern image stabilization works.

127
00:06:34,040 --> 00:06:37,130
>> So I'm here with CS50's
own Dan Coffey, jogging

128
00:06:37,130 --> 00:06:39,330
along the Charles River
on Harvard's campus.

129
00:06:39,330 --> 00:06:41,755
Now if Dan were just using
a camera to shoot this,

130
00:06:41,755 --> 00:06:44,670
the image would be pretty
shaky, definitely not stable.

131
00:06:44,670 --> 00:06:50,070
He's using a technique called image
stabilization which should, hopefully,

132
00:06:50,070 --> 00:06:51,806
be stabilizing the image.

133
00:06:51,806 --> 00:06:54,200
Can we shoot the rest of this inside?

134
00:06:54,200 --> 00:06:57,530

135
00:06:57,530 --> 00:06:58,070
>> OK.

136
00:06:58,070 --> 00:06:59,030
Image stabilization.

137
00:06:59,030 --> 00:06:59,720
What is it?

138
00:06:59,720 --> 00:07:00,449
How does it work?

139
00:07:00,449 --> 00:07:02,740
DAN COFFEY: So for many years,
the TV and film industry

140
00:07:02,740 --> 00:07:05,430
have been trying to get more dynamic
shots by introducing movement,

141
00:07:05,430 --> 00:07:07,304
but it's a challenge to
keep them stabilized.

142
00:07:07,304 --> 00:07:10,780
You've seen The West Wing maybe
where they do the walk and talk shot?

143
00:07:10,780 --> 00:07:13,620
And basically what they use
for that is a steady cam,

144
00:07:13,620 --> 00:07:15,640
which is a big rig that you wear.

145
00:07:15,640 --> 00:07:19,854
It's a vest with an arm that isolates
the camera from the user and counter

146
00:07:19,854 --> 00:07:21,395
balances it with a series of weights.

147
00:07:21,395 --> 00:07:23,103
But it takes a really
long time to set up

148
00:07:23,103 --> 00:07:25,000
and it's very complicated
to actually use.

149
00:07:25,000 --> 00:07:28,130
>> There are new developments in software
that you can use where you can make

150
00:07:28,130 --> 00:07:31,074
adjustments in Mac or PC which
sometimes work, sometimes they don't.

151
00:07:31,074 --> 00:07:33,240
But one of the latest
developments is actually this.

152
00:07:33,240 --> 00:07:34,720
This is the MoVI M10.

153
00:07:34,720 --> 00:07:38,490
It's a really neat piece of equipment
from our friends at Freefly Systems.

154
00:07:38,490 --> 00:07:41,491
And basically, it uses a series of
gimbal axes to stabilize your camera.

155
00:07:41,491 --> 00:07:42,698
DAVID MALAN: What's a gimbal?

156
00:07:42,698 --> 00:07:46,380
DAN COFFEY: So a gimbal is a set of
rings that each spins on its own axis

157
00:07:46,380 --> 00:07:49,970
and basically isolates each direction,
either the x, the y, or the z.

158
00:07:49,970 --> 00:07:52,420
And really just makes it
very smooth and fluid.

159
00:07:52,420 --> 00:07:55,850
So this M10 is a large gimbal
and has three axes on it--

160
00:07:55,850 --> 00:08:00,420
one here for the tilt, it's got one in
the back for the roll, and one up top

161
00:08:00,420 --> 00:08:01,110
for the pan.

162
00:08:01,110 --> 00:08:03,490
And I can actually show you if you
want to see how these actually work.

163
00:08:03,490 --> 00:08:03,760
>> DAVID MALAN: Yeah, sure.

164
00:08:03,760 --> 00:08:05,110
>> DAN COFFEY: So if you
look here in the software,

165
00:08:05,110 --> 00:08:06,680
this is their Freefly Configurator.

166
00:08:06,680 --> 00:08:09,680
And it's basically outputting
diagnostic information right now.

167
00:08:09,680 --> 00:08:12,214
But you see we have motor tilt,
motor roll, and motor pan.

168
00:08:12,214 --> 00:08:14,130
And as I actually pan
the camera, you're going

169
00:08:14,130 --> 00:08:15,910
to see the blue lines
start to go up and down.

170
00:08:15,910 --> 00:08:16,576
>> DAVID MALAN: OK.

171
00:08:16,576 --> 00:08:17,775
So that represents the--

172
00:08:17,775 --> 00:08:20,340
>> DAN COFFEY: It's the resistance
of the motor pushing back

173
00:08:20,340 --> 00:08:22,570
against me because the M10
always wants to come back

174
00:08:22,570 --> 00:08:23,370
to rest in the same position.

175
00:08:23,370 --> 00:08:23,600
>> DAVID MALAN: OK.

176
00:08:23,600 --> 00:08:25,850
So the taller, the lower the
bar, the more resistance.

177
00:08:25,850 --> 00:08:29,350
DAN COFFEY: Yeah, the more intensity
that the motor's using to fight me.

178
00:08:29,350 --> 00:08:32,219
If I tilt, you can see the
red line doing the same thing.

179
00:08:32,219 --> 00:08:32,844
And then roll--

180
00:08:32,844 --> 00:08:34,120
>> DAVID MALAN: The green line up and down.

181
00:08:34,120 --> 00:08:36,600
>> DAN COFFEY: So these are the three
axes we're stabilizing against.

182
00:08:36,600 --> 00:08:38,690
And so this is not normally how
you would operate it, right?

183
00:08:38,690 --> 00:08:40,289
So if I actually pick
this up-- and here,

184
00:08:40,289 --> 00:08:41,260
why don't you actually hang on to it.

185
00:08:41,260 --> 00:08:42,690
>> DAVID MALAN: Yeah, sure.

186
00:08:42,690 --> 00:08:43,429
Thank you.

187
00:08:43,429 --> 00:08:45,410
>> DAN COFFEY: And now
you can see how little

188
00:08:45,410 --> 00:08:47,740
the camera moves when you hit the edge.

189
00:08:47,740 --> 00:08:49,987
The window, if you will,
it starts to pan with you.

190
00:08:49,987 --> 00:08:51,820
That's actually set in
the software as well.

191
00:08:51,820 --> 00:08:52,210
>> DAVID MALAN: I see.

192
00:08:52,210 --> 00:08:53,520
>> DAN COFFEY: But there's
another really neat feature.

193
00:08:53,520 --> 00:08:56,830
If you are in a more complicated
shoot, you can turn on this remote,

194
00:08:56,830 --> 00:09:00,590
have a second camera operator
actually do the nitty gritty control.

195
00:09:00,590 --> 00:09:02,660
So I can now pan, flex this control.

196
00:09:02,660 --> 00:09:05,270
I can tilt and I can actually roll.

197
00:09:05,270 --> 00:09:09,160
So in this set-up, you would actually
be the one moving the camera physically

198
00:09:09,160 --> 00:09:11,160
and I would connect a
wireless video transmitter

199
00:09:11,160 --> 00:09:13,900
to the camera, put a
receiver here on a monitor,

200
00:09:13,900 --> 00:09:17,740
and then I could actually, just like a
video game, operate the camera for you.

201
00:09:17,740 --> 00:09:18,896
>> DAVID MALAN: Nice.

202
00:09:18,896 --> 00:09:20,720
>> DAN COFFEY: So I'll put it
back in single operator mode,

203
00:09:20,720 --> 00:09:22,810
but you can get a sense of
how smooth it actually is.

204
00:09:22,810 --> 00:09:24,230
>> DAVID MALAN: Yeah, no, absolutely.

205
00:09:24,230 --> 00:09:26,290
And I have an idea.

206
00:09:26,290 --> 00:09:27,107
Want to follow me?

207
00:09:27,107 --> 00:09:27,815
DAN COFFEY: Sure.

208
00:09:27,815 --> 00:09:29,770
DAVID MALAN: OK.

209
00:09:29,770 --> 00:09:33,280
So we're here in the bathroom to test
out some actual image stabilization

210
00:09:33,280 --> 00:09:36,000
in front of, well, the
only mirror we have.

211
00:09:36,000 --> 00:09:39,310
And I thought it'd be interesting to
see just how much the camera moves when

212
00:09:39,310 --> 00:09:42,055
I actually move my arms
up, down, left and right.

213
00:09:42,055 --> 00:09:43,930
DAN COFFEY: So let's
see the pan, tilt, roll.

214
00:09:43,930 --> 00:09:44,888
DAVID MALAN: All right.

215
00:09:44,888 --> 00:09:46,136
Here we go.

216
00:09:46,136 --> 00:09:47,959
I'm really moving it.

217
00:09:47,959 --> 00:09:50,250
DAN COFFEY: So I see a little
bit movement, but I mean,

218
00:09:50,250 --> 00:09:52,300
you would never operate
it like that either.

219
00:09:52,300 --> 00:09:54,710
>> DAVID MALAN: No, definitely not.

220
00:09:54,710 --> 00:09:58,684

221
00:09:58,684 --> 00:09:59,600
DAN COFFEY: All right.

222
00:09:59,600 --> 00:10:01,130
So David, let's get serious this time.

223
00:10:01,130 --> 00:10:02,900
We'll do a test where you
actually go up the stairs

224
00:10:02,900 --> 00:10:04,620
and I will lead you with
the stabilized MoVI,

225
00:10:04,620 --> 00:10:06,360
and Andrew will actually
come next to me.

226
00:10:06,360 --> 00:10:07,310
Come on over Andrew.

227
00:10:07,310 --> 00:10:08,965
And we'll see what it
looks like side-by-side.

228
00:10:08,965 --> 00:10:09,510
>> DAVID MALAN: Got it.

229
00:10:09,510 --> 00:10:10,370
>> DAN COFFEY: OK.

230
00:10:10,370 --> 00:10:11,050
Here we go.

231
00:10:11,050 --> 00:10:13,648
Ready to go up the stairs
in three, two, one, go.

232
00:10:13,648 --> 00:10:27,073

233
00:10:27,073 --> 00:10:27,573
Hi Shelley.

234
00:10:27,573 --> 00:10:30,940

235
00:10:30,940 --> 00:10:32,901
All right, David, why
don't you take this?

236
00:10:32,901 --> 00:10:35,150
Take all that you've learned
today and put it together

237
00:10:35,150 --> 00:10:36,358
and we'll get the final shot.

238
00:10:36,358 --> 00:10:39,422

239
00:10:39,422 --> 00:10:40,380
DAVID MALAN: All right.

240
00:10:40,380 --> 00:10:41,370
Here we go.

241
00:10:41,370 --> 00:11:02,160

242
00:11:02,160 --> 00:11:06,310
>> DAN COFFEY: And now,
60 seconds of gimbals.

243
00:11:06,310 --> 00:11:07,250
>> SPEAKER 3: Uh-oh.

244
00:11:07,250 --> 00:11:08,272
Look out!

245
00:11:08,272 --> 00:11:09,290
Let's face it.

246
00:11:09,290 --> 00:11:10,820
Kids spill stuff.

247
00:11:10,820 --> 00:11:13,980
But now, parents can
relax whenever kids snack.

248
00:11:13,980 --> 00:11:17,120
Introducing the GyroBowl,
the world's first ever

249
00:11:17,120 --> 00:11:20,550
snack bowl that spins and
spins and stuff stays in.

250
00:11:20,550 --> 00:11:25,145
The GyroBowl is 100% totally,
absolutely, kid-proof!

251
00:11:25,145 --> 00:11:28,587
Just fill the GyroBowl
and you're ready to go.

252
00:11:28,587 --> 00:11:30,170
SPEAKER 4: The magic is in the middle.

253
00:11:30,170 --> 00:11:32,545
The GyroBowl works just like a bowl.

254
00:11:32,545 --> 00:11:36,240
>> SPEAKER 3: GyroBowl's inner
bowl rotates 360 degrees

255
00:11:36,240 --> 00:11:39,605
and magically stays open
side up, no matter what!

256
00:11:39,605 --> 00:11:43,510
So the GyroBowl keeps all your
snacks inside, however you bounce,

257
00:11:43,510 --> 00:11:45,020
swing, or fly!

258
00:11:45,020 --> 00:11:49,126
Now, kids can use the amazing
GyroBowl as a super snack contraption.

259
00:11:49,126 --> 00:11:53,215
Fill it up with raisins or
cereal and rev up the action!

260
00:11:53,215 --> 00:11:56,185
>> SPEAKER 5: Kids loves the
amazing GyroBowl because it's fun

261
00:11:56,185 --> 00:11:58,340
and it never spills!

262
00:11:58,340 --> 00:12:01,582
>> SPEAKER 3: Pack crackers and
grapes and get on with the chase!

263
00:12:01,582 --> 00:12:04,186
And when mom drives
to the store, GyroBowl

264
00:12:04,186 --> 00:12:06,017
keeps the snacks off the floor.

265
00:12:06,017 --> 00:12:07,850
DAVID MALAN: Now, you
may recall, I recently

266
00:12:07,850 --> 00:12:10,070
spent time with his
CS50's own Colton Ogden.

267
00:12:10,070 --> 00:12:16,180
And this guy here, the NAO Robot that
was loaned to us by CS50's friend

268
00:12:16,180 --> 00:12:19,040
Professor Radhika Nagpal
in the robotics group.

269
00:12:19,040 --> 00:12:21,040
Now, of course, robots
don't all take this form.

270
00:12:21,040 --> 00:12:23,520
In fact, we recently saw
this guy here playing soccer

271
00:12:23,520 --> 00:12:25,140
with President Barack Obama.

272
00:12:25,140 --> 00:12:27,560
>> But it turns out that
even soccer playing robots

273
00:12:27,560 --> 00:12:28,850
can come in different forms.

274
00:12:28,850 --> 00:12:32,080
In fact, pictured here
are two custom made robots

275
00:12:32,080 --> 00:12:35,580
by Professor Radhika Nagpal's research
group, with whom we sat down recently

276
00:12:35,580 --> 00:12:40,340
to better understand how they and
you can build your own soccer playing

277
00:12:40,340 --> 00:12:42,960
robots and pit them in
competition against each other

278
00:12:42,960 --> 00:12:46,185
in an international RoboCup competition.

279
00:12:46,185 --> 00:12:47,810
RADHIKA NAGPAL: My name Radhika Nagpal.

280
00:12:47,810 --> 00:12:50,420
I'm a professor at Harvard University.

281
00:12:50,420 --> 00:12:52,570
And I do bio-inspired robotics.

282
00:12:52,570 --> 00:12:56,379
So I'm really interested in how
groups can work together really well.

283
00:12:56,379 --> 00:12:58,170
ERIC SCHLUNTZ: So my
name is Eric Schluntz.

284
00:12:58,170 --> 00:13:00,520
I'm studying electrical
engineering at Harvard University,

285
00:13:00,520 --> 00:13:00,970
>> KATE DONAHUE: I'm Kate Donahue.

286
00:13:00,970 --> 00:13:04,550
I'm a sophomore at Harvard College
and concentrating in math and physics.

287
00:13:04,550 --> 00:13:06,360
So I'm part of RFC Cambridge.

288
00:13:06,360 --> 00:13:08,250
It's a joint Harvard/MIT team.

289
00:13:08,250 --> 00:13:10,294
We basically build
robots that play soccer.

290
00:13:10,294 --> 00:13:13,210
RADHIKA NAGPAL: So the challenge of
the RoboCup competition-- and it's

291
00:13:13,210 --> 00:13:16,510
an international competition that
was started by people in the US

292
00:13:16,510 --> 00:13:22,760
and Japan actually-- is to create a team
of robots that can play and possibly

293
00:13:22,760 --> 00:13:25,077
win against the world
champions at the world cup.

294
00:13:25,077 --> 00:13:27,410
KATE DONAHUE: There are teams
from all around the world.

295
00:13:27,410 --> 00:13:29,910
And because we're so far spread
out, it's really hard for us

296
00:13:29,910 --> 00:13:31,800
to get to test the robots
against each other.

297
00:13:31,800 --> 00:13:34,560
So it's basically just sort
of like a soccer match.

298
00:13:34,560 --> 00:13:37,550
There will be some round robin
games and then a final competition.

299
00:13:37,550 --> 00:13:40,290
And it's a chance to see
how our robots stack up

300
00:13:40,290 --> 00:13:42,740
against others and just exchange ideas.

301
00:13:42,740 --> 00:13:46,480
>> RADHIKA NAGPAL: If you think about
little kids playing soccer and older

302
00:13:46,480 --> 00:13:49,050
people playing soccer and
think about the difference,

303
00:13:49,050 --> 00:13:54,040
like all the things that a little kid
cannot do that an older person can,

304
00:13:54,040 --> 00:13:56,310
computer science has
to fill that whole gap.

305
00:13:56,310 --> 00:13:58,380
>> ERIC SCHLUNTZ: So you
could say, I want the robot

306
00:13:58,380 --> 00:14:00,030
to go behind the ball
to set up for a shot.

307
00:14:00,030 --> 00:14:02,155
But what you really have
to tell the computer to do

308
00:14:02,155 --> 00:14:07,474
is find the vector between the ball and
the goal and go there, minus an offset.

309
00:14:07,474 --> 00:14:10,640
And you really need the computer science
people to express yourself in a way

310
00:14:10,640 --> 00:14:11,932
that the robots can understand.

311
00:14:11,932 --> 00:14:14,556
KATE DONAHUE: We all work on very
different parts of the robot,

312
00:14:14,556 --> 00:14:16,080
but we really need to coordinate.

313
00:14:16,080 --> 00:14:20,720
It's a big challenge and it's great
when we all work on something together.

314
00:14:20,720 --> 00:14:22,560
So we'll build the
mechanical part of it,

315
00:14:22,560 --> 00:14:25,484
and then the electrical engineers
will make the circuit boards,

316
00:14:25,484 --> 00:14:28,150
and the computer science people
will have done their simulations

317
00:14:28,150 --> 00:14:30,850
and then try and figure out how
they can combine that and make

318
00:14:30,850 --> 00:14:32,500
the robot actually move.

319
00:14:32,500 --> 00:14:35,880
>> RADHIKA NAGPAL: I think really
robotics is often about iteration.

320
00:14:35,880 --> 00:14:37,460
You do take one step forward.

321
00:14:37,460 --> 00:14:39,140
You take two steps back.

322
00:14:39,140 --> 00:14:40,680
You try to make one thing better.

323
00:14:40,680 --> 00:14:42,430
It makes something else worse.

324
00:14:42,430 --> 00:14:45,471
>> ERIC SCHLUNTZ: On the computer science
team, we've made a lot of progress

325
00:14:45,471 --> 00:14:46,850
on our artificial intelligence.

326
00:14:46,850 --> 00:14:48,926
We threw out all the old
strategy code and have

327
00:14:48,926 --> 00:14:51,460
been making something that's
much more adaptive to how

328
00:14:51,460 --> 00:14:53,260
the other team is playing.

329
00:14:53,260 --> 00:14:56,400
So on defense, we do things like
ranking the most dangerous players

330
00:14:56,400 --> 00:14:59,535
and covering them in a man
to man defense based on that.

331
00:14:59,535 --> 00:15:02,785
And then our offense, we generate these
maps over the entire field of how good

332
00:15:02,785 --> 00:15:06,017
the spot is and then assign our
robots to these dynamically.

333
00:15:06,017 --> 00:15:07,850
RADHIKA NAGPAL: They
need to be able to see.

334
00:15:07,850 --> 00:15:10,580
They need to be able to
understand the world.

335
00:15:10,580 --> 00:15:13,720
They need to be able to move
fast and turn and manipulate.

336
00:15:13,720 --> 00:15:15,740
They need to be able to
notice their teammates

337
00:15:15,740 --> 00:15:18,150
and understand what they're doing.

338
00:15:18,150 --> 00:15:20,390
They need to have a strategy.

339
00:15:20,390 --> 00:15:23,120
And they need to adapt their
strategy because their opponent will

340
00:15:23,120 --> 00:15:24,590
be doing things all the time.

341
00:15:24,590 --> 00:15:26,742
And so you can't have
a pre-determined plan.

342
00:15:26,742 --> 00:15:27,950
You have to be able to adapt.

343
00:15:27,950 --> 00:15:29,110
>> KATE DONAHUE: Since
last year's competition,

344
00:15:29,110 --> 00:15:32,239
we've done a lot of advances,
especially in the wheel design.

345
00:15:32,239 --> 00:15:34,280
We've shifted the motors
down and made everything

346
00:15:34,280 --> 00:15:37,590
much more compact, which has allowed
us to move our center of gravity

347
00:15:37,590 --> 00:15:40,047
down, which allows us to
go faster and also put

348
00:15:40,047 --> 00:15:42,630
in a dribbler, which is something
we've wanted for a long time

349
00:15:42,630 --> 00:15:44,672
but just haven't been able
to make fit until now.

350
00:15:44,672 --> 00:15:47,046
ERIC SCHLUNTZ: So each of the
circuit boards on the robot

351
00:15:47,046 --> 00:15:48,410
has a different purpose.

352
00:15:48,410 --> 00:15:54,490
The four big ones, there, there, and
there, each control one of the motors.

353
00:15:54,490 --> 00:15:58,120
So that basically takes a
signal from the computer,

354
00:15:58,120 --> 00:16:00,840
decides how fast the wheel
should spin, and sends

355
00:16:00,840 --> 00:16:03,102
the correct voltage to
the wheels to do that.

356
00:16:03,102 --> 00:16:06,310
So like this board here
controls this motor and this one

357
00:16:06,310 --> 00:16:08,500
here controls this motor.

358
00:16:08,500 --> 00:16:10,940
>> We also have these two
boards in the middle.

359
00:16:10,940 --> 00:16:17,110
This one right here controls charging
these big capacitors for the kicker.

360
00:16:17,110 --> 00:16:22,290
This board here controls when the robot
kicks by using this light sensor right

361
00:16:22,290 --> 00:16:24,310
here to see when the
ball is in front of it.

362
00:16:24,310 --> 00:16:28,156
It also controls the dribbler here
which we use to put backspin on the ball

363
00:16:28,156 --> 00:16:29,530
so we can move backwards with it.

364
00:16:29,530 --> 00:16:31,170
>> KATE DONAHUE: It's not
just you're trying to win.

365
00:16:31,170 --> 00:16:33,045
It's that you're trying
to advance knowledge.

366
00:16:33,045 --> 00:16:35,750
And so you work on whatever
you work on and then you

367
00:16:35,750 --> 00:16:38,950
have to release a paper saying
exactly what you did that's so cool,

368
00:16:38,950 --> 00:16:42,000
and how other people can do that
and they can build on your work.

369
00:16:42,000 --> 00:16:45,170
And so if there's something so
advanced that someone comes up with,

370
00:16:45,170 --> 00:16:47,890
everybody can sort of draw on that.

371
00:16:47,890 --> 00:16:51,750
>> You can have that for one year and maybe
nobody else can use it for that year.

372
00:16:51,750 --> 00:16:54,682
But then the next year,
everybody will have modified it

373
00:16:54,682 --> 00:16:55,890
and have done the same thing.

374
00:16:55,890 --> 00:17:00,130
So it's really just moving forwards
and not staying in the same place.

375
00:17:00,130 --> 00:17:03,719
>> ERIC SCHLUNTZ: I definitely want to
be working on robotics in my career.

376
00:17:03,719 --> 00:17:05,760
I think that there's just
a lot of amazing things

377
00:17:05,760 --> 00:17:08,810
that can be done to automate
things, to make cars safer,

378
00:17:08,810 --> 00:17:12,490
to make just really everything work
automatically so that people don't have

379
00:17:12,490 --> 00:17:16,069
to do things that are dangerous or dull.

380
00:17:16,069 --> 00:17:19,109
There's just so many things that
robots can do better than people.

381
00:17:19,109 --> 00:17:22,769
And I think that as a society we need
to start doing those to free people up

382
00:17:22,769 --> 00:17:25,020
to do more interesting things.

383
00:17:25,020 --> 00:17:28,750
>> DAVID MALAN: This is indeed our season
finale and our 10th of 10 episodes.

384
00:17:28,750 --> 00:17:31,980
And it's truly remarkable
how in just 10 episodes

385
00:17:31,980 --> 00:17:33,530
how many mistakes we have made.

386
00:17:33,530 --> 00:17:36,930
In fact, CS50's own Shelley Westover--
whom you may recall from such films

387
00:17:36,930 --> 00:17:41,370
as-- recently went through hours
of footage of both live episodes

388
00:17:41,370 --> 00:17:44,780
and rehearsals thereof to find
some of our favorite memories

389
00:17:44,780 --> 00:17:47,190
to share them with you.

390
00:17:47,190 --> 00:17:47,940
>> Hello world.

391
00:17:47,940 --> 00:17:50,694
This is CS50 Live.

392
00:17:50,694 --> 00:17:53,610
So if you see me trip, if you see
me misspeak, if you see me screw up,

393
00:17:53,610 --> 00:17:57,885
all of that is happening literally
right now in Cambridge, Massachusetts.

394
00:17:57,885 --> 00:17:58,965
Oh, hi world.

395
00:17:58,965 --> 00:18:00,040
Drum roll.

396
00:18:00,040 --> 00:18:04,800
Persp-- uh, persec-- pause the video
if you would like. [INAUDIBLE].

397
00:18:04,800 --> 00:18:05,340
[STUTTERING]

398
00:18:05,340 --> 00:18:10,580
>> Is Mark Zunkerburn's favorite pa--
to protect our nuclear missile.

399
00:18:10,580 --> 00:18:11,990
Keeping an eye as usual.

400
00:18:11,990 --> 00:18:13,350
Bugle itself.

401
00:18:13,350 --> 00:18:13,850
Gaggles.

402
00:18:13,850 --> 00:18:14,880
Good episude for you.

403
00:18:14,880 --> 00:18:17,640
It's actually quite-- Ah, it ends.

404
00:18:17,640 --> 00:18:18,850
You may recall.

405
00:18:18,850 --> 00:18:20,330
Head to this UR here.

406
00:18:20,330 --> 00:18:21,330
>> SPEAKER 6: This is CS50.

407
00:18:21,330 --> 00:18:22,255
Ah.

408
00:18:22,255 --> 00:18:24,130
DAVID MALAN: And now I
made the blooper reel.

409
00:18:24,130 --> 00:18:24,630
Fantastic.

410
00:18:24,630 --> 00:18:28,369

411
00:18:28,369 --> 00:18:29,910
SPEAKER 7: Should we redo the ending?

412
00:18:29,910 --> 00:18:31,800
How should we do the ending?

413
00:18:31,800 --> 00:18:34,924
>> DAVID MALAN: Photos of Jason
Hirschhorn dressed as a punmpkin.

414
00:18:34,924 --> 00:18:35,715
SPEAKER 8: Oh, boy.

415
00:18:35,715 --> 00:18:37,070
I don't know if I want
people to see that.

416
00:18:37,070 --> 00:18:37,736
>> DAVID MALAN: No.

417
00:18:37,736 --> 00:18:41,371
Now it's photos of Jason
Hirsch dressed as a boy.

418
00:18:41,371 --> 00:18:44,120
SPEAKER 9: And if you're interested,
I can actually show you how--

419
00:18:44,120 --> 00:18:45,010
DAVID MALAN: Yeah, absolutely.

420
00:18:45,010 --> 00:18:47,140
SPEAKER 9: He's a little
off-balance this morning.

421
00:18:47,140 --> 00:18:49,411
He hasn't had his coffee yet.

422
00:18:49,411 --> 00:18:51,896
>> SPEAKER 10: Whoa!

423
00:18:51,896 --> 00:18:52,890
Oh god.

424
00:18:52,890 --> 00:18:57,860

425
00:18:57,860 --> 00:18:59,470
>> DAVID MALAN: From-- where's he from?

426
00:18:59,470 --> 00:19:01,350
>> SPEAKER 11: Right about--
right where my arm is,

427
00:19:01,350 --> 00:19:02,933
you can see like the white characters.

428
00:19:02,933 --> 00:19:03,676
There's the pole.

429
00:19:03,676 --> 00:19:06,342
DAVID MALAN: They don't know
that's the-- you should point here.

430
00:19:06,342 --> 00:19:06,966
SPEAKER 11: Oh.

431
00:19:06,966 --> 00:19:14,625

432
00:19:14,625 --> 00:19:16,125
>> DAVID MALAN: Can you hear me, world?

433
00:19:16,125 --> 00:19:17,208
RAMON GALVAN: Hello world.

434
00:19:17,208 --> 00:19:18,280
Welcome to CS50 Live.

435
00:19:18,280 --> 00:19:19,910
I'm Ramon Galvan.

436
00:19:19,910 --> 00:19:23,200
>> DAVID MALAN: And-- and I'm David Malan.

437
00:19:23,200 --> 00:19:26,050
>> RAMON GALVAN: And today,
I'm hosting today's episode.

438
00:19:26,050 --> 00:19:27,892
>> DAVID MALAN: Well, with me.

439
00:19:27,892 --> 00:19:28,600
RAMON GALVAN: OK.

440
00:19:28,600 --> 00:19:29,500
OK.

441
00:19:29,500 --> 00:19:30,210
Oh, [BLEEP]

442
00:19:30,210 --> 00:19:31,984
>> SPEAKER 12: Don't say
[BLEEP] on the air!

443
00:19:31,984 --> 00:19:34,400
RAMON GALVAN: Oh, [BLEEP] He'll
be the Robin to my Batman,

444
00:19:34,400 --> 00:19:37,205
the Andy Richter to my Conan,
the Cheech to my Chong today.

445
00:19:37,205 --> 00:19:39,830
This is most definitely a serious
thing that we're doing today.

446
00:19:39,830 --> 00:19:40,992
This is not a joke.

447
00:19:40,992 --> 00:19:43,950
Dropbox has been quite a fuss lately
because I know nothing about this.

448
00:19:43,950 --> 00:19:44,940
What is this about?

449
00:19:44,940 --> 00:19:46,300
That was all above me.

450
00:19:46,300 --> 00:19:51,082
And this is something I don't know of.

451
00:19:51,082 --> 00:19:54,189
We also take a tour of
third glass-- third deg--

452
00:19:54,189 --> 00:19:55,230
DAVID MALAN: Right there.

453
00:19:55,230 --> 00:19:58,326
It allows you to swipe credit
cards on your iPhone in order

454
00:19:58,326 --> 00:20:00,034
to process payments.

455
00:20:00,034 --> 00:20:01,450
RAMON GALVAN: I have a flip phone.

456
00:20:01,450 --> 00:20:03,378
Let's play the clip.

457
00:20:03,378 --> 00:20:05,306
One, two--

458
00:20:05,306 --> 00:20:07,029
>> DAVID MALAN: That was the first ever.

459
00:20:07,029 --> 00:20:07,820
RAMON GALVAN: What?

460
00:20:07,820 --> 00:20:08,800
DAVID MALAN: That was the first ever.

461
00:20:08,800 --> 00:20:09,010
RAMON GALVAN: OK.

462
00:20:09,010 --> 00:20:10,195
To host the first ever--

463
00:20:10,195 --> 00:20:12,727

464
00:20:12,727 --> 00:20:14,810
DAVID MALAN: I was in
graduate school at the time.

465
00:20:14,810 --> 00:20:16,476
RAMON GALVAN: And I was in fourth grade.

466
00:20:16,476 --> 00:20:18,809
Although I love Zamyla, I
would much rather not spend--

467
00:20:18,809 --> 00:20:20,725
DAVID MALAN: Spend half
as much time with her.

468
00:20:20,725 --> 00:20:21,641
RAMON GALVAN: Exactly.

469
00:20:21,641 --> 00:20:27,580

470
00:20:27,580 --> 00:20:29,640
>> DAVID MALAN: Come on out, Zamyla!

471
00:20:29,640 --> 00:20:33,616
This was CS50, and this was terrifying.

472
00:20:33,616 --> 00:20:34,990
RAMON GALVAN: This is terrifying.

473
00:20:34,990 --> 00:20:39,750
Made a little sizzle roll to encapsulate
the debauchery that took place.

474
00:20:39,750 --> 00:20:41,003
>> DAVID MALAN: I love you.

475
00:20:41,003 --> 00:20:41,690
Aww.

476
00:20:41,690 --> 00:20:43,300
>> RAMON GALVAN: I love you.

477
00:20:43,300 --> 00:20:45,836
Unlike David, who circles you.

478
00:20:45,836 --> 00:20:50,015

479
00:20:50,015 --> 00:20:51,390
DAVID MALAN: Where are my slides?

480
00:20:51,390 --> 00:20:53,810
Oh.

481
00:20:53,810 --> 00:20:55,359
That's it for CS50 Live.

482
00:20:55,359 --> 00:20:57,150
Thanks so much to this
week's contributors,

483
00:20:57,150 --> 00:21:00,040
to every one behind the
camera, and thank you to you

484
00:21:00,040 --> 00:21:02,520
for tuning in this whole season.

485
00:21:02,520 --> 00:21:04,622
This was CS50.

486
00:21:04,622 --> 00:21:08,824
>> [MUSIC - SEMISONIC, "CLOSING TIME"]

487
00:21:08,824 --> 00:21:32,224