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Astro Biology

Know When Milky Way Collision Occur - 0 views

www.astrobio.net/...ollision-100-million-years-ago

milky way satellite galaxy news from nasa solar system planet

shared by Astro Biology on 20 Nov 14 - No Cached
  • Astro Biology on 20 Nov 14
     
    NASA scientist have found proof that our Milky Way had an encounter with a small galaxy or massive dark matter structure perhaps as recently as 100 million years ago. Are you also interested to know how galaxies form, evolve and interact?
  • Astro Biology on 20 Nov 14
     
    NASA scientist have found proof that our Milky Way had an encounter with a small galaxy or massive dark matter structure perhaps as recently as 100 million years ago. Are you also interested to know how galaxies form, evolve and interact?
York Jong

RoboLogo - Teaching Children how to program Interactive Robots - 0 views

web.mit.edu/...robologo.html

grammar javacc logo mit robot

shared by York Jong on 09 Sep 07 - Cached
  • All of the procedures take a discrete ``gear'' to specify the speed. The reasons for this are two-fold; first, by limiting the power of the truck, we simplify the interface to children. Secondly, it allows use to calibrate the ``gears'' so that, for example, 10 seconds forward in first gear is the same distance as 10 seconds backward in first gear.
  • The limitation of LOGO however is the lack of feedback from the environment. There is no way of expressing an event occuring in the outside world.
  • Simple constructs in iLogo extend the original LOGO language with interactivity capabilities of reading sensors and transfering control to different parts of the program.
  • ...6 more annotations...
  • These above rules handle all of the commands and expressions of the iLogo language except for the DoUnlessCommand. This command will execute a list of commands unless a boolean condition is met. If so, control is switched to a new list of commands for handling the exception condition.
  • Each stage of the compiler is designed using the Visitor pattern described in the book Design Pattern by Eric Gamma, et al. This pattern allows tree traversers to be created as seperated objects, instead of doing all traversals as methods of the nodes of the tree
  • We decided to use the JavaCC/JJTree tools created by Sun for generating a custom parser for our iLogo language written in Java.
  • The language must have primitives which allow the user of the language to write programs which easily transfer control based upon outside stimuli, in this case sensors on the truck.
  • An LM18293 push-pull motor driver connects the programmable counter array (PCA) of the 8051 to the truck's motors.
    • York Jong
      York Jong on 09 Sep 07
       
      LM18293 is a DC motor driver.
  • We took the Berkeley Logo language design as our base and then added a primitive for reading sensor and an exception-based control structure.
  • York Jong on 09 Sep 07
     
    RoboLogo is a system that enables children to program interactive robots. Children can program a robotic truck that interacts with the environment without having to deal with low-level implementation details.
Astro Biology

Earth's magnetic field has flipped - 0 views

www.astrobio.net/...eld-flip-within-human-lifetime

news from nasa solar system planets in our

shared by Astro Biology on 20 Oct 14 - No Cached
  • Astro Biology on 20 Oct 14
     
    The new discovery indicates that the intensity of Earth's magnetic field is decreasing 10 times faster, leading some geophysicists to predict a reversal within a few thousand years.
  • Astro Biology on 20 Oct 14
     
    The new discovery indicates that the intensity of Earth's magnetic field is decreasing 10 times faster, leading some geophysicists to predict a reversal within a few thousand years.
Astro Biology

Extreme Ultraviolet Image of a Significant Solar Flare - 0 views

www.astrobio.net/...e-of-a-significant-solar-flare

origin of life on earth nasa solar system planets in our news from

shared by Astro Biology on 21 Oct 14 - No Cached
  • Astro Biology on 21 Oct 14
     
    The sun emitted a significant solar flare which is classified as an X1.1-class flare. X-class denotes the most intense flares, while the number provides more information about its strength.
  • Astro Biology on 21 Oct 14
     
    The sun emitted a significant solar flare which is classified as an X1.1-class flare. X-class denotes the most intense flares, while the number provides more information about its strength.
York Jong

The Playful World: How Technology Is Transforming Our Imagination - 0 views

books.google.com/books

book choice education robot toy

shared by York Jong on 09 Sep 07 - Cached
  • York Jong on 09 Sep 07
     
    A trenchant analysis of the new "gaming" technology introduces readers to the interactive toys that will soon influence an entire generation of young users.
York Jong

BEAM Pieces -- Integrated circuits - 0 views

library.solarbotics.net/...parts_elect_ic.html

5star beam collection electronics ic motor robot solar survey

shared by York Jong on 27 May 07 - Cached
  • 1381s are CMOS voltage-controlled triggers -- these "gate" a source until the voltage is above some "trip" limit, at which point it is allowed onto a third pin
  • We use them as 3- or 5-volt triggers
  • This chip is often considered the heart of Nv net technology
  • ...22 more annotations...
  • The '240 is often called "the bicore chip," because we can take advantage of the 240's inverters to turn a single 74*240 into a bicore
  • The '240 also has tri-state outputs, so an enable line can be used to turn its outputs on and off simply (good for adding reversing capability to a 'bot).
  • any *cores built with a 74*04 will require additional logic "downstream" to amplify the current to levels sufficient to drive a moto
  • Schmitt triggers can't easily be used in suspended bicore implementations
  • use its buffers as little current amplifiers
  • it is usable for either grounded or suspended bicore designs (but better for suspended)
  • 74HC/HCTxx non-buffers (74HC14 or 74HC04) draw about half of the current consumption, and have about half the drive current compared to HC / HCT buffer chips (74HC240 or 74HC245). Non-buffer chips are thus better for oscillators, say Nv and Nu applications; they are not suited for use in driving motors.
  • 74AC is best suited for motor driver applications with all inputs driven rail to rail.
  • The '245 is an octal buffer chip, and so has 8 channels of buffering power available for our misuse. This chip was designed for data transmission uses, but we'll misuse it as a motor driver chip
  • The '244 provides us with 8 (thus the "octal") buffers, enableable in banks of 4. This is a very useful chip for amplifying small currents
  • it can drive up to 4 motors in 2 directions each, or you can "buddy up" inputs and outputs to drive fewer motors at higher current
  • it can drive up to 4 motors in 2 directions each, or you can "buddy up" inputs and outputs to drive fewer motors at higher current
  • If you can't find 1381s locally, you might have better luck finding its European cousin, the TC-54 -- for details on it
  • Note that if you need more than about 200 mA per motor, you'll need to use an H-bridge, or some similar motor driver
  • The ideal BEAM circuit would use a low (2V-3V) voltage core and sensors combined with level shifting high (5-6V) volt motor drivers to maximize efficiency.
  • 74ACxxx used in typical BEAM applications uses 4x more supply current than does 74HC/HCTxxx.
  • York Jong on 27 May 07
     
    The following material is intended to cover usage and part selection details of ICs you're most likely to see in BEAM robots.
York Jong

Nv neurons and Nv nets - 0 views

www.solarbotics.net/...starting_nvnet.html

3star beam neuron nv robot theory

shared by York Jong on 26 May 07 - Cached
  • We assume that the slowly changing waveform at the Nv input produces a single output transition when it crosses the Nv switching threshold. This is accomplished by using a 74HC14 or similar CMOS Schmitt trigger. When 74HC04 or 74HC240s are used for Nv inverters some nasty oscillations occur during switching which makes these inverters unsuitable for most Nv networks greater than 2 Nv in series.
  • York Jong on 26 May 07
     
    On this page, we'll tackle two challenging topics -- Nv neurons (the building block of advanced BEAM circuits), and Nv nets (networks of Nv Neurons, designed to do our bidding).
York Jong

Facilitating Robot Learning - 0 views

robotics.usc.edu/...learning.html

5star behavior-based delicious imitation imported learning multi-robot robot theory

shared by York Jong on 26 May 07 - Cached
  • York Jong on 26 May 07
     
    In our own work, we pursue an experimental approach in two highly uncertain, dynamic, and high-dimensional domains: multi-robot learning, and learning by imitation. Both force us to deal with perceptual and action uncertainty, non-stationarity, and real-t
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