ENTRIES TAGGED "feedback"

Four short links: 22 November 2013

Four short links: 22 November 2013

GAFE MOOCs, Recommendations Considered Self-Fulfilling Prophecy, Glitch Art Given, and Cool Visual Hack

  1. Google Educator MOOCs — online courses for teachers who use Google in their classrooms.
  2. Algorithms and AccountabilityThus, the appearance of an autocompletion suggestion during the search process might make people decide to search for this suggestion although they didn’t have the intention to. A recent paper by Baker and Potts (2013) consequently questions “the extent to which such algorithms inadvertently help to perpetuate negative stereotypes”. (via New Aesthetic Tumblr)
  3. Glitch Content Enters Public Domain — amazing contribution of content, not just “open sourcing” but using CC0 to give the public the maximum possible rights for reuse.
  4. Sprite Lampa tool to help game developers combine 2D art, such as digital painting or pixel art, with dynamic lighting. This is pretty darn cool. (via Greg Borenstein)
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Self-Adaptive Is Not The Same As Feedback

Favoring behavior over environment

In a series of posts (Part 1, Part 2, Part 3, Part 4, Part 5, and Part 6), we have introduced the idea of feedback control as a way to keep complex systems on track, even when subject to uncertainty and change.

It is easy to be confused at this point, and to think that feedback is nothing more than an “adaptive system” that can modify its behavior in response to changes in its environment. But that would not be right. It depends on what quantity you are monitoring! A feedback system does not respond to changes in the environment—a feedback system changes specifically in response to changes in its own behavior. That’s a big difference.

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Feedback Controllers

Exploring the PID controller

In the previous parts of this series (Part 1, Part 2, Part 3, and Part 4), we introduced feedback as a design principle or paradigm, that can help to keep systems “on track”, even in the presence of uncertainty and change. In this post, we will begin to explore more closely what this all means in practice.

Loop Diag

Consider the feedback loop shown in the Figure. The controlled system is a cache, and we have a controller that adjusts the size of the cache in order to maintain a desired cache hit rate. (Making the cache larger will result in a greater number of hits and hence will drive the hit rate up.) We also have a desired value for the hit rate as reference value or “setpoint” (supplied on the left). The tracking error is calculated as the difference between setpoint and actual hit rate and is provided as input to the controller.

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Programming with feedback

Feedback is an elegant and effective way to control complex, dynamic processes.

Everyone knows what feedback is. It’s when sound systems suddenly make loud, painful screeching sounds. And that answer is correct, at least partly.

Control theory, the study and application of feedback, is a discipline with a long history. If you’ve studied electrical or mechanical engineering, you’ve probably confronted it. Although there’s an impressive and daunting body of mathematics behind control theory, the basic idea is simple. Whenever you have a varying signal, you can use feedback to control the signal, giving you a consistent output. Screaming amps at a concert are nothing but a special case in which things have gone wrong.

We use control theory all the time, without even thinking about it. We couldn’t walk if it weren’t for our body’s instinctive use of feedback; upsetting that feedback system (for example, by spinning to become dizzy) makes you fall. When you’re driving a car, you ease off the accelerator when it’s going too fast. You press the accelerator when it’s going too slow. If you undercorrect, you’ll end up going too fast (or stopping); if you overcorrect, you’ll end up jerking forward, slamming on the brakes, then jerking forward again — possibly with disastrous consequences. Cruise control is nothing more than a robotic implementation of the same feedback loop. Read more…

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Why feedback?

Maintaining a desired behavior

In two previous posts (Part 1 and Part 2) we introduced the idea of feedback control. The basic idea is that we can keep a system (any system!) on track, by constantly monitoring its actual behavior, so that we can apply corrective actions to the system’s input, to “nudge” it back on target, if it ever begins to go astray.

This begs the question: Why should we, as programmers, software engineers, and system administrator care? What’s in it for us?

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The Feedback Principle

Gracefully maintain a desired value in the presence of uncertainty and change

In a previous post, we introduced the basic feedback concept. Now it is time to take a closer look at this idea.

Feedback is a method to keep systems on track. In other words, feedback is a way to make sure a system behaves in the desired fashion. If we have some quality-of-service metric in mind, then feedback is a reliable method to ensure that our system will achieve and maintain the desired value of this metric, even in the presence of uncertainty and change.

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How to Get Fast, Cheap Feedback on Your Product with Tiny Tests

User research you can do now

There’s a lot of advice about how to do great user research. I have some pretty strong opinions about it myself.

But, as with exercise, the best kind of research is the kind that you actually DO.

So, in the interests of getting some good feedback from your users right now, I have some suggestions for Tiny Tests. These are types of research that you could do right this second with very little preparation on your part.

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What is a Tiny Test?

Tiny Tests do not take a lot of time. They don’t take a lot of money. All they take is a commitment to learning something from your users today.

Pick a Tiny Test that applies to your product and get out and run one right now. Oh, ok. You can wait until you finish the post.

Unmoderated tests

Dozens of companies now exist that allow you to run an unmoderated test in a few minutes. I’ve used UserTesting.com many times and gotten some great results really quickly. I’ve also heard good things about Loop11 and several others, so feel free to pick the one that you like best.

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The hidden language and "wonderful experience" of product reviews

The hidden language and "wonderful experience" of product reviews

Panagiotis Ipeirotis on the phrases and formatting of effective product reviews.

How much is an Amazon review — good or bad — worth? Computer scientist and NYU professor Panagiotis Ipeirotis analyzed the text in thousands of Amazon reviews to find out.

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Top Stories: January 2-6, 2012

Top Stories: January 2-6, 2012

Welcome to the feedback economy, a guide for empowered patients, and 3 developer topics that will define 2012.

This week on O'Reilly: Alistair Croll explained why the information economy is giving way to the feedback economy, Fred Trotter examined the epatient movement, and we looked at the three big stories that will shape the developer world in the months ahead.

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The feedback economy

The feedback economy

Companies that employ data feedback loops are poised to dominate their industries.

We're moving beyond an information economy. The efficiencies and optimizations that come from constant and iterative feedback will soon become the norm for businesses and governments.

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