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Submission + - How to Build a TimesMachine (

necro81 writes: The NY Times has an archive, the TimesMachine, that allows users to find any article from any issue from 1851 to the present day. Most of it is shown in the original typeset context of where an article appeared on a given page — like sifting through a microfiche archive. But when original newspaper scans are 100-MB TIFF files, how can this information be conveyed in an efficient manner to the end user? These are other computational challenges are described in this blog post on how the TimesMachine was realized.

Comment Re:Free market dogwhistle (Score 1) 84

Certainly makes the case for people being able to generate their own power with a choice of utilities as a back up.

It makes the case, but that is hardly an overwhelming counter-argument. Huge numbers of electricity customers, possibly even a majority, cannot avail themselves to this. For instance: renters cannot typically put solar panels on the roof of their landlord's structure; the electrical demand for a large building is much larger than the available renewables can provide. The capital costs of self-generation - such as diesel generators or natural gas fuel cells - is quite high, and most folks simply are not cut out to manage that kind of machinery.

It's an option for some - and an increasing number of folks are availing themselves to it. This ought to be a concern for utilities generally, and for anyone who utilizes the grid (and pays for it) in any fashion.

Comment Re:record-shattering recording instruments (Score 1) 507

You, like Ted Cruz, seem to be laboring under the assumption that because it is a satellite, all rockety-spacey expensive and such, it must be better than measurements on the ground.

Satellite measurements have some advantages, such as being able to use one instrument to survey the entire Earth. On the other hand, these aren't direct measurements of temperature at ground level, in the stratosphere, or deep in the ocean; they're indirect measurements based on radiation, and have relatively large error bars compared to direct measurements. Satellite observations should not be relied upon in isolation to uphold or refute a hypothesis. We have data from multiple independent sources - they should all be utilized.

Comment Does it count as "evidence" (Score 3, Funny) 258

A computer model that predicts the existence of a ninth planet (of substantial mass, ejected into a distant orbit, early in the solar system) does not, by the usual scientific method, constitute evidence. Evidence of its existence would be certain observables that others could also observe and verify: perturbations in the orbits of other planets, detection in a telescope, etc.

This is a prediction by a hypothesis - nothing more. I could create a model that predicts the existence of dragons that fart nerve gas - that does not count as "evidence of an impending apocalypse," although that would surely generate many clicks.

Comment Re:Wow (Score 1) 216

Most of the cold "heat capacity" in the fridge comes from the chilled contents, not the air inside it. Generally, it is most efficient to have the fridge filled with lots of stuff that has a large heat capacity - replacing air volume with, say, bottles of water. Doing so will make the fridge less susceptible to, say, having the cold air replaced with warmer air. It will also reduce short-cycling of the compressor, which will extend the life of the fridge and improve its efficiency.

Comment Re:landing location (Score 3, Informative) 114

Generally, rockets begin a roll maneuver that starts them heading downrange very soon after clearing the tower. For instance, the Saturn V would perform its roll maneuver about 20-30 seconds after liftoff.

A huge fraction (90% ?) of the energy an object must gain in order to reach orbit is tangential velocity. By comparison the gain in potential energy from gaining altitude is relatively small.

Comment Re:Give us the patent number (Score 1) 174

Many corporations have policies that ban employees from looking at patents. If you look at the patent, you can later be found liable for intentional infringement. It is better to just ignore existing patents, and document your research, so you can latter show it was independently developed

Which is unfortunate, since the theory behind patents is that they should be read by others, and used as a springboard for further innovation and development. The reality is far from this ideal, alas. Most patents make for difficult reading, even if you are in the field. and, as you point out, you expose yourself to an infringement liability if you outwardly try to develop something new beyond someone else's patent.

Comment Re:Except they used regular SMS (Score 1) 291

My read on it is they mean the vendor has zero knowledge of how to break the encryption to gain access to a user's data

Oh, the vendor has plenty of knowledge on how to break the encryption - they developed it, after all - it's just that the knowledge of how the encryption works doesn't lead to any feasible way to break it in any reasonable timeframe. The knowledge the vendor has about breaking the encryption is "brute force is your only recourse, and we hope you can wait a loooong time."

Comment Feynmann (Score 4, Insightful) 337

Having no personal experience in choosing textbooks (just buying many of the assigned texts in college - not much choice there), my view on the process is heavily influenced by Richard Feynmann's recounting the time he served on the California Curriculum Commission in Surely You're Joking, Mr. Feynmann. For those who haven't read it before, here's his chapter on Judging Books by Their Covers.

Comment Re:buy our dying batteries (Score 1) 73

Meh, if the pack has a certain nameplate capacity (kWh of storage, kW of output power), then it should not matter much if packs are new or old. The physical size will be different, since you'll need more aged batteries to match the capacity of new batteries. I'd be more interested in seeing the terms of the warranty.

Comment Re:3D Printed Gimbal (Score 2) 15

In other words, the most complicated way yet devised of sending an electrical signal about 10cm.

Perhaps, although this method has some advantages to it:

  1. it does not require invasive retrofitting of the existing wheelchair joystick. As shown in the video, attaching the gimbal requires able-hands only about 10 seconds. I would guess that an attendant would still be able to use that joystick to drive the chair, even with the gimbal attached (although usually for such patients, a second, more easily accessible attendant joystick is part of the controls)
  2. The communications between the joystick (usually called the user control panel, or UCP) and the motor drives on the chair are often CANbus-based, but not always, and the protocol varies by manufacturer. The details of the communications are generally not public, meaning that they'd need to be reverse-engineered for each make and model of chair - which is a tremendous hurdle to development and widespread adoption. The eyedrivomatic avoids these electrical differences. there may still be some manufacturer-specific changes for properly mounting the gimbal on different chairs, but most folks are generally more adept at mechanical hacking than electrical and software.
  3. As one who works on embedded electronics all the time, I can't tell you how gratifying it is to see the workings of the software realized out in meatspace. That is, when the eyedrivomatic is working, you can see it working. Silent and hidden electronic signals provide little indication that they are working, or in what way they are not working.

Considering that the developer is not an engineer by training, and has done most of this on his own, I applaud what he has been able to pull off.

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