Profile cover photo
Profile photo
Brian Douglas Smith

Post has attachment
Rain passed through the Bay Area last night, including a light blanket of snow at the James Lick Observatory on Mt. Hamilton. The City of Palo Alto maintains the San Francisquito Creek Camera at West Bayshore that displays a static image that updates about every 5-minutes. I love weather and am also curious how it interacts with the local mountains, foothills and valleys.

I was inspired to create a stop-motion animation of the storm as it passed through last night. The time period is from 6PM Friday night to 7AM Saturday morning. It was great fun to discover what happened at the creek the next morning!
Add a comment...

Post has attachment
Cyber Monday with Ruby and Twilio - I created a Ruby script that will send you a text message whenever a new item is added to the homepage. Fun to watch the online deals appear, including what is considered "hot"
Add a comment...

Post has shared content
Why it's important to measure quantiles, and not just report the "average". 

Vertical axis is response time in ms.  The green line is the median -- 50% of all requests are answered by that point.  Red line is 90%, blue is 95%, yellow is 99%.  Notice how the green line, is even trending down slightly.  And the fix that was deployed that was supposed to improve the response times for "most" people did have an effect (the drop in the red line.)   But the behaviour for the remaining 10% certainly requires some investigation, especially that upward-trending 1%.
Add a comment...

Post has attachment
I created a Ruby gem to visualize recent Iraq violence data shared in a Google Spreadsheet by +AFP  Here is an example Rickshaw.js chart +DashingD3js 
Add a comment...

Post has shared content
*Below is Open Engineering University’s tuition free 16 weeks drone engineering course syllabus.  It consists of 13 chapters in the course textbook*  We would cover a chapter per week. Week 14 through week 16 will be devoted to completing a drone built project of your choice (This will include posting a to the community video demonstration of your drone). If you do not have the recourses to build a drone, documentation file of your project will suffice. Course will begin July 3, 2013. To enroll for the course,  click on the following  course community page:

*Chapter 1 Introduction 1*
1.1 System Architecture 1
1.2 Design Models 4
1.3 Design Project 6

*Chapter 2 Coordinate Frames 8*
2.1 RotationMatrices 9
2.2 MAV Coordinate Frames 12
2.3 Airspeed,Wind Speed, and Ground Speed 18
2.4 TheWind Triangle 20
2.5 Differentiation of a Vector 24
2.6 Chapter Summary 25
2.7 Design Project 27
*Chapter 3 Kinematics and Dynamics 28*
3.1 State Variables 28
3.2 Kinematics 30
3.3 Rigid-body Dynamics 31
3.4 Chapter Summary 37
3.5 Design Project 38

*Chapter 4 Forces and Moments 39*
4.1 Gravitational Forces 39
4.2 Aerodynamic Forces andMoments 40
4.3 Propulsion Forces andMoments 52
4.4 Atmospheric Disturbances 54
4.5 Chapter Summary 57
4.6 Design Project 58

*Chapter 5 Linear Design Models 60*
5.1 Summary of Nonlinear Equations of Motion 60
5.2 Coordinated Turn 64
5.3 Trim Conditions 65
5.4 Transfer Function Models 68
5.5 Linear State-space Models 77
5.6 Reduced-order Modes 87
5.7 Chapter Summary 91
5.8 Design Project 92

*Chapter 6 Autopilot Design Using Successive Loop Closure 95*
6.1 Successive Loop Closure 95
6.2 Saturation Constraints and Performance 97
6.3 Lateral-directional Autopilot 99
6.4 Longitudinal Autopilot 105
6.5 Digital Implementation of PID Loops 114
6.6 Chapter Summary 117
6.7 Design Project 118

*Chapter 7 Sensors for MAVs 120*
7.1 Accelerometers 120
7.2 Rate Gyros 124
7.3 Pressure Sensors 126
7.4 Digital Compasses 131
7.5 Global Positioning System 134
7.6 Chapter Summary 141
7.7 Design Project 141

*Chapter 8 State Estimation 143*
8.1 Benchmark Maneuver 143
8.2 Low-pass Filters 144
8.3 State Estimation by Inverting the Sensor Model 145
8.4 Dynamic-observer Theory 149
8.5 Derivation of the Continuous-discrete Kalman Filter 151
8.6 Attitude Estimation 156
8.7 GPS Smoothing 158
8.8 Chapter Summary 161
8.9 Design Project 162

*Chapter 9 Design Models for Guidance 164*
9.1 AutopilotModel 164
9.2 Kinematic Model of Controlled Flight 165
9.3 Kinematic Guidance Models 168
9.4 Dynamic Guidance Model 170
9.5 Chapter Summary 172
9.6 Design Project 173

*Chapter 10 Straight-line and Orbit Following 174*
10.1 Straight-line Path Following 175
10.2 Orbit Following 181
10.3 Chapter Summary 183
10.4 Design Project 185

*Chapter 11 Path Manager 187*
11.1 Transitions BetweenWaypoints 187
11.2 Dubins Paths 194
11.3 Chapter Summary 202
11.4 Design Project 204

*Chapter 12 Path Planning 206*
12.1 Point-to-Point Algorithms 207
12.2 Coverage Algorithms 220
12.3 Chapter Summary 223
12.4 Design Project 224

*Chapter 13 Vision-guided Navigation 226*
13.1 Gimbal and Camera Frames and Projective Geometry 226
13.2 Gimbal Pointing 229
13.3 Geolocation 231
13.4 Estimating Target Motion in the Image Plane 234
13.5 Time to Collision 238
13.6 Precision Landing 240
13.7 Chapter Summary 244
13.8 Design Project 245

*Week 14 - Week 16: Final Drone Project*
Drone built project of your choice (This will include posting a to the community video demonstration of your drone). If you do not have the resources to build a drone, documentation file of your project will suffice. 

APPENDIX A: Nomenclature and Notation 247
APPENDIX B: Quaternions 254
B.1 Quaternion Rotations 254
B.2 Aircraft Kinematic and Dynamic Equations 255
B.3 Conversion Between Euler Angles and
Quaternions 259
APPENDIX C: Animations in Simulink 260
C.1 Handle Graphics inMatlab 260
C.2 Animation Example: Inverted Pendulum 261
C.3 Animation Example: Spacecraft Using Lines 263
C.4 Animation Example: Spacecraft Using Vertices and
Faces 268
APPENDIX D: Modeling in Simulink Using S-Functions 270
D.1 Example: Second-order Differential Equation 270
APPENDIX E: Airframe Parameters 275
E.1 Zagi Flying Wing 275
E.2 Aerosonde UAV 276
APPENDIX F: Trim and Linearization in Simulink 277
F.1 Using the Simulink trim Command 277
F.2 Numerical Computation of Trim 278
F.3 Using the Simulink linmod Command to
Generate a State-space Model 282
F.4 Numerical Computation of State-space Model 284
APPENDIX G: Essentials from Probability Theory 286
APPENDIX H: Sensor Parameters 288
H.1 Rate Gyros 288
H.2 Accelerometers 288
H.3 Pressure Sensors 289
H.4 Digital Compass/Magnetometer 289
H.5 GPS 290
Add a comment...

Post has shared content
Excellent video showing what Google Glass can do and what it's like to wear them.
Add a comment...

Post has shared content
WBench by is a tool that uses the HTML5 performance timing API to benchmark end user load times for websites.

Very nice. Now since it's a command-line utility, you'd probably expect it to use PhantomJS, but au contraire! It uses Chome via chromedriver (the WebDriver adapter) to get accurate network metrics from Chrome's network stack. And since WBench is based on WebDriver, you can also have it run the numbers with Firefox as well. 
Add a comment...

Post has attachment
PETMAN the human-like robot. Seems logical that robo-dog would get a companion. Robo-velociraptors next?
Add a comment...
Wait while more posts are being loaded