Showing posts from 2005

Peer review, human nature and scientific publication

Peer review determines what gets published and what gets funded in science and technology, at least in academia. Since most (all?) institutions evaluate their researchers based on their publication and fund raising records, the defining principle of scientific life. It is what distinguishes the respected professional from the mad scientist operating unchecked in his garage/home office. A bulletin from the Office of Management and Budget titled "Final Information Quality Bulletin for Peer Review" ( ) gives the following definition: "Peer review is one of the important procedures used to ensure that the quality of published information meets the standards of the scientific and technical community. It is a form of deliberation involving an exchange of judgments about the appropriateness of methods and the strength of the author's inferences. Peer review involves the review of a draft product for quality by spec

Synthesis, analysis and invariants

"If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is." -- J. H. Von Neumann One can wonder why computer vision (CV) has not benefited from the increase in computational power as much as computer graphics (CG), although the two fields grew from the same seminal work (Roberts, 1965). CG is a synthesis activity, that starts from mathematical models of some physical objects and their environment, and applies some mathematical models of light and material physics to create an image of the objects in their environments under various conditions. Better models, and computational power directly translate into more realistic images. The models are designed by humans. Computer vision is an analysis activity, that seeks to form models of objects, environments, situations, activities, etc., from images (still pictures or video streams). Depending on their intended purpose, these models are not necessarily of the same natur

Scientific freedom

"I have just one wish for you--the good luck to be somewhere where you are free to maintain the kind of integrity I have described, and where you do not feel forced by the need to maintain your position in the organization, or financial support, or so on, to lose your integrity. May you have that freedom." Richard P. Feynman, "Cargo Cult Science," adapted from the Caltech commencement address given in 1974, published in "Surely you're joking, Mr. Feynman" (Norton, 1985).


"Don't speak unless you can improve on the silence" -- proverb, apparently spanish...

Bandwidth vs. latency

I recently attended a robotics seminar in which the speaker made an interesting point about machines outperforming humans (in some domain), but unfortunately used the word bandwidth when he really meant latency . His point was that machines can react much faster than humans. Indeed, humans have relatively long reaction time, ranging in order from a few tens of milliseconds, to a just short of a lifetime, depending on the stimulus, the complexity of the analysis, and the complexity of the action. When it comes to latency, for simple reactive actions, current computers and robots can already outperform humans, sometimes by several orders of magnitude. On the other hand, humans have extremely large input bandwidth. The amount of sensory data that humans can absorb and process per unit of time is still much larger than what computers can deal with, both in terms of physical bandwidth, and computing bandwidth. In the world of digital signal processing, where bandwidth directly constrains p

'Don't settle'

"Your work is going to fill a large part of your life, and the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to love what you do. If you haven't found it yet, keep looking. Don't settle. As with all matters of the heart, you'll know when you find it." "Your time is limited, so don't waste it living someone else's life. Don't be trapped by dogma--which is living with the results of other people's thinking. Don't let the noise of other's opinions drown out your own inner voice. And most important, have the courage to follow your heart and intuition." Excerpts from Steve Jobs' graduation address at Stanford University. Full text available at:

Software design

"To a man with a hammer, everything looks like a nail. To a Computer Scientist, everything looks like a language design problem. [...] My early work clearly treated modularisation as a design issue, not a language issue. [...] We are still trying to undo the damage caused by the early treatment of modularity as a language issue and, sadly, we still try to do it by inventing languages and tools." David Parnas, in : Premkumar Devanbu, Bob Balzer, Don Batory, Gregor Kiczales, John Launchbury, David Parnas, Pen Tarr, "Modularity in the New Millenium: A Panel Summary," in Proceedings of the 25th International Conference on Software Engineering, Portland, OR, 2003, pp.723-724.

What is software

"In the context of a book on software design, it should be obvious that we are concerned with designing software. It is far from clear, however, just what the word means. We can approach software from many different perspectives, each with its own implications for design. In this book, we emphasize software as a medium for the creation of virtualities --the world in which a user of the software perceives, acts and responds to experiences." Terry Winograd, Introduction to "Bringing Design to Software."

Fear of the unknown

"You come to me for advice, but you can't cope with anything you don't recognize. Hmmm. So we'll have to tell you something you already know but make it sound like news, eh? Well, business as usual, I suppose." Douglas Adams, "Mostly Harmless."

The right tools make all the difference

A screw is best used with a screw-driver. The screw-driver is as critical to screwing as the screw. If all one has is a hammer, and all one studies is nailing and hammering, it will be difficult to grasp, let alone come up with, the concept of screwing. Screws handled with a hammer bear the mark of laziness and short-term reward. But, once mastered, screwing should not be allowed to eclipse nailing: while some tasks require screwing, others clearly call for nailing. Only by understanding not only each independently, but also how they relate to each other, can one decide when to use them optimally. Then it is time to start learning about riveting...

Academic credits

"I recently learned a disagreeable fact: there are influential scientists in the habit of putting their names to publications in whose composition they have played no part. Apparently, some senior scientists claim joint authorship of a paper when all that they have contributed is bench space, grant money and an editorial read-through of the manuscript. For all I know, entire scientific reputations may have been built on the work of students and colleagues!" Richard Dawkins, Preface to the 1989 edition of "The Selfish Gene."

What you see is what you expect

"[...] a scientist must also be absolutely like a child. If he sees a thing, he must say that he sees it, whether it was what he thought he was going to see or not. See first, think later, then test. But always see first. Otherwise, you will only see what you were expecting." Douglas Adams, "So Long and Thanks for all the Fish."

Welcome to

Sign of the times, this blog is now my official personal home page. It is obviously work in progress. If you are looking for professional information, follow the link to my home page at USC .