paper: designing for usability

My prelims are coming sooner that I'd like to admit, and so I need to get hopping reading a bunch of papers. Fortunately, over the past semester our reading group read over half the assigned papers, but for those that are left I will be posting my summaries here for my own archival purposes (including some back-posts for previously read papers). Perhaps they will be of use to someone else as well, so I might as well make these public...

First up is "Designing for Usability: Key Principles and What Designers Think" by John D. Gould and Clayton Lewis. This paper was originally published in 1985 in the Communications of the ACM, and outlines the iterative design philosophy that is central to modern Human-Computer Interaction. The paper describes three central design principles (early focus on users, empirical measurement, and iterative design) and includes a survey of designers trying to ascertain how common and/or obvious these principles are. The paper also rebuts arguments against the use of these principles and presents a case study of these principles in action.

My biggest problem with this article is that the authors are too unsympathetic to the demands that a deadline-driven project can make. They seem to advocate iterating "as long as it takes", which while desirable is not particularly feasible. To be fair, they acknowledge these pressures and give some cogent arguments for why the costs of iteration are not as high as one might otherwise suspect. But what is missing in the methodology are strategies and techniques for optimizing the design as much as possible within bounded resources. Later work has attempted to address some of these issues, including discount usability methods (e.g., heuristic evaluation) and rapid ethnography techniques (e.g., David Millen's paper).

Designing for Usability: Key Principles and What Designers Think
John D. Gould and Clayton Lewis
Communications of the ACM, March 1985 - Volume 28, Number 3

• The Principles
  • Early Focus on Users and Tasks
    • Understand who the users will be
    • Study cognitive, behavioral, anthropometric, and attitudinal characteristics
    • Study the nature of the work to be accomplished
  • Empirical Measurement
    • User test prototypes on intended users
    • Observe, record, and analyze performance and reactions
  • Iterative Design
    • Cycles of discovering and fixing problems
    • Design, Prototype, Evaluate, Re-Design, ...
• Principles are NOT obvious
  • Survey discovered that most designers at a human factors conference missed most of the principles
    • 62% - Early focus on users
    • 40% - Empirical measurement
    • 20% - Iterative design
• Principles in more detail
  • Early Focus on Users
    • Understanding potential users (as opposed to identifying, describing, etc)
    • Bringing design team into direct contact with potential users
    • Make contact prior to system design
    • Participatory design
      • Have typical users participate in early formulation stages
  • Empirical Measurement
    • Behavioral measurements of learnability and usability
    • Conducting studies very early in the development process
    • Designed not to study a prototype but how people use and react to the prototype
  • Iterative Design
    • A process to ultimately ensure goals are met
• Why the principles are undervalued
  • Not Worth Following
  • Confusion with Similar but Critically Different Ideas
  • Value of Interaction with Users is Misestimated
    • User diversity is underestimated
    • User diversity is overestimated
    • Belief that users do not know what they need
      • A priori vs. knowing it when they see it
    • Belief that my job doesn not require it or need it
  • Competing Approaches
    • Belief in the power of reason
      • Reason alone is likely to miss true work practices and cost structures
    • Belief that design guidelines should be sufficient
      • Guidelines ill-suited for highly context-dependent choices
    • Belief that good design means getting it right the first time
      • Humans unpredictable, necessitating an empirical approach
  • Impractical
    • Belief that the development process will be lengthened
      • Assumptions
        • Usability work must be added to the end of the development cycle
        • Responding to tests must be time consuming
      • Rebuttals
        • User testing can start before a system is built
          • Discount methods - paper prototyping, wizard of oz studies
          • Helps bootstrap project - something tangible to motivate, stimulate thought
        • Modular design, multi-tiered designs - decouple UI from system internals
      • Still has price, but not as high as supposed
      • Poor design brings costs of it's own (support, vendor costs, updates)
    • Belief that iteration is just expensive fine-tuning
      • No, it is a basic design philosophy
    • Belief in the power of technology to succeed
      • From user's perspective, user interface is the product
• Elaboration of Principles
  • Initial Design Phase
    • Preliminary specification of the user interface
    • Collect critical information about users
    • Develop testable behavioral goals
      • Description of intended users (demographic)
      • The tasks to be performed and circumstances of user
      • The measurements of interest
    • Organize the work
      • Software, manuals, etc should be built by the same group
  • Iterative Development Phase
    • Test behavioral goals, continuous evaluation
    • Modification of the interface
    • Fast, flexible prototyping
    • Highly modular implementations
    • Be prepared for results that dictate radical change
    • User comments and think-aloud protocol can help point the way for designing fixes

comedies of all sorts

Which is funnier, fact or fiction? Since they exist in a continuous feedback loop with each other, I suppose the answer is: yes. But I'll spare you any further theorizing and let you be the judge...

Governor calls tax hike a Christian duty
Axis Of Evil angered by snubbing
Arianna vs. the Terminator?
Gigli Focus Groups Demand New Ending In Which Both Affleck And Lopez Die
Warner Says Pentagon To Scrap Terror-Futures Market Plan

movies i must see

Two movies I recently discovered that I must see soon:

Masked and Anonymous - Bob Dylan as an old troubador in a dark parallel universe in which the United States is run by a dictatorial President? Plus it's directed by regular Curb Your Enthusiasm (only the funniest show currently on TV) director Larry Charles, and also stars John Goodman, Jeff Bridges, Penelope Cruz, ... for those of you who still need to know more, here's the Salon review.

Revolution OS - A documentary on the Open Source movement, including interviews with Linus Torvalds (of linux fame), Brian Behlendorf (of the Apache project), Rob Malda (of Slashdot) and Ricahrd Stallman (of GNU / Free Software Foundation). I don't know how the film ranks in terms of quality, but I'll probably pre-emptively purchase it anyway.

technews

Some interesting articles today from ACM TechNews:

Report: Inadequate IT contributed to 9/11 intelligence failure
Socially Intelligent Software: Agents Go Mainstream

concert: squarepusher

Last night we headed into the city for some musical mayhem. We arrived around 11pm at the Mezzanine, a large club tucked away in one of the alleys between Mission and Market in the SOMA district of San Francisco. Alterna-kids, ravers, and the assorted lot of hipsters (ourselves included) had all come out to witness the spectacle that is Squarepusher (aka Tom Jenkinson), Warp Records recording artist and drum and bass virtuouso.

When we arrived, Luke Vibert (aka Wagon Christ), was working the crowd, while appearing to passively meditate over his laptop. He played a great mix, with lots of elements of dub, funk, and soul. My only gripe was that he overdid it on the dub vocals, as I have a rather low threshold for crazy over-stimulated rastas yelling incessantly in my ear. Just after midnight, Luke stepped off and Squarepusher came on.

I've been a fan of Squarepusher for about a year now and was excited to see him live for the first time. He didn't disappoint. Many electronic artists spend their sets twiddling knobs or playing with their laptops, trying to imbue the pre-programmed set with a little live performance. Squarepusher, on the other hand, walks out carrying a giant 6-string bass, with a fret-board so big you could eat thanksgiving dinner off of it. He didn't waste any time. He set the programmed tracks rolling and just went nuts on his bass, with hard-hitting, insanely fast breakbeats and improvised, lightning-quick bass runs pulsing through the Mezzanine's $10,000+ sound system. Acoustic energy saturated the room, so thick it penetrated every part of your body, even parts you didn't know you had. In addition, there was particularly intense rapid strobe lighting throughout the performance, resulting in a nearly complete sensory overload. My eyes and ears were crying rape, but my brain was begging for more.

The show was great, though certainly indulgent. I usually think of Squarepusher as being a bit more accessible than some of his colleagues (e.g. the ever enigmatic Aphex Twin), but his performance was anything but restrained. Tom would let the drums accelerate out of control, many times creating a cacophany that was nigh-impossible to dance to (with your feet, anyway) and went on many extended bass-outs (impatient souls might even refer to it as "wanking"). Squarepusher would stop at fairly regular intervals to throw his hand up in the air, his prompt for the crowd to shout. It was almost as if the music was so overpowering, the crowd had to be told when to cheer as opposed to hold on for dear life. The highlight of the set for me was the performance of Squarepusher's single "Come On My Selector" (the same track that was adapted into a wonderful music video by Chris Cunningham). It struck the right balance between out of control drums and spiraling bass licks, coming down to earth just enough for you to be compelled to dance, commanding you to throw your body every which way before being re-inveloped in auditory chaos.

talk: jan pedersen

Today Jan Pedersen, former PARC researcher and current Chief Scientist of AltaVista, spoke at the PARC Forum. His talk was entitled Internet Search: Past, Present, and Future. It seems particularly relevant given my recent exposure to personalized search start-up Kaltix. Jan primarily covered the developmental and economic history of search engines and spoke about current search technologies. Read on for my notes from the talk.

Notes: PARC Forum, July 24, 2003

Internet Search: Past, Present, and Future
Jan Pedersen, Chief Scientist, AltaVista

• Search Engine Timeline
• Pre-Cursors
• Information Retrieval research
• Discovery that free text queries win over Boolean queries (salton)
• 1^st Generation
• 1993 NCSA Mosaic
• Webcrawler
• Yahoo!
• Lycos (400k indexed pages)
• Infoseek
• Power Players
• 1994 AltaVista
• DEC labs, advanced query syntax, large index
• Actually a showcase for DEC Alpha machines
• 1996 Inktomi
• Berkeley Systems Lab, Eric Brewer
• Massively parallel solution
• 2^nd Generation
• Relevance
• 1998 DirectHit
• re-ranking results using user click-through rates
• 1998 Google
• re-ranking results using link authority
• Size
• 1999 FAST/AllTheWeb
• scalable architecture
• User Matters
• 1996 AskJeeves
• Users ask questions, natural language input
• Money
• 1997 Goto/Overture
• Pay-for-performance, pay for search rankings
• 3^rd Generation
• Consolidation
• 2002 Yahoo! Purchases Inktomi
• 2003 Overture purchases AltaVista, AllTheWeb
• 2003 MSN announces intention of own search engine
• 2003 Yahoo! Purchases Overture
• Maturity
• $2B market, $6B by 2005
• Requires large capital investment, limiting newcomers
• Although Gigablast is an exception (2 years private development, mid-size search index)
• Traffic focused on Yahoo!, Google, AOL
• Consumer use driven by brand marketing
• Economics
• Overview
• Popularity
• Search is the most used Internet application after email
• 400M queries / day
• High bar for quality in search results
• Users spend 1.5 hours / week searching
• Experience search rage after 12 minutes
• Expensive centralized service
• Indices cover billions on documents
• The FAST index is 30TB large!
• Query service is high performance application
• Google claims 50K machines
• Cost: $0.001 per query
• Amortizes capital, operations, and engineering costs
• Business Models
• Early Monetization Models
• Subscription services
• Infoseek, Northern Lights
• Failed: users can find equal results for free
• Advertising
• Invented by Infoseek, Netscape
• Untargeted ads (banners, sponsorships)
• Limited keyword targeting (low keyword coverage)
• Portalitis
• Search not profitable enough, need stickier services
• Email, shopping, content channels
• Tried by Excite, Infoseek, AltaVista -> disastrous
• Led to lack of focus on core technology that opened the door for 2^nd generation search engines.
• Performance Search Market
• Goto/Overture – keyword auction
• With 80k+ advertisers get good keyword coverage, currently exceeds 40%
• Pay per click revenue
• Marketers easily project to conversions
• Search engine projects to CPM
• Triple Win
• Consumer: relevant ads
• Marketer: qualified traffic
• Search Engine: high-monetized impressions
• Successful
• Overture makes ~$1B/year
• Strategy adopted by Google
• Current Evolution
• Greater automation
• self-serve sign up, automated bidding
• Increased competition
• Google splits market with Overture
• 19% of Yahoo! Revenue from paid listings
• MSN Search most profitable MS product group by headcount (50 people)
• Trends available online
• SearchEngineWatch.com (Neilsen / Netrating)
• Traffic concentration
• Google > Yahoo! > MSN…
• Loyalty
• AOL > Google > IS > Yahoo!
• Technology
• WWW Size
• Dynamic pages -> effectively infinite pages
• Domains: .com (23M), .net (4M), .org (2.5M)
• Crawling
• Index parameterized by size and freshness
• Batch (discover, grab, index) and Incremental (mixed) approaches to crawling
• Relative Size
• Google – 3B, FAST– 2.5B, AltaVista – 1B
• Anchor text only index (discovered links that are not yet crawled)
• FAST 1.2B fully indexed pages (rest anchor text only)
• Google 1.5 fully indexed pages
• Freshness
• Graph from (G. Notess)
• Note use of hybrid indices
• Subindices with differing update rates
• Ranking
• 2.4 query terms -> 2B documents -> 10 highly relevant pages. All in 300ms.
• Trouble queries: Travel, Cobra, John Ellis
• Ingredients
• Keyword match
• Anchor text
• Link authority
• Click-through rates
• SPAM – An Arms Race
• Manipulate content purely to influence ranking
• Dictionary spam, link sharing, domain hijacking, link farms
• Robotic use of search results
• Meta-search engines
• Search engine optimizers
• Fraud
• UI
• Ranked results lists
• Document summaries are critical
• Hit highlight, dynamic abstract
• NO RECENT INNOVATIONS!
• Blending
• Pre-defined segmentation (e.g. paid listing)
• Intermixed results from multiple sources
• Future
• Question Answering
• Natural Language Processing
• Dumais, SIGIR 2002 paper
• WWW as language model
• New Contexts
• Ubiquitous searching
• Implicit searching
• New Tasks
• Local / community search
• Questions…
• Personalization
• Currently searchers are anonymous
• Personalized search requires some form of user model
• How much does the engine need to know?
• Geographic location
• Use context of surfing behavior
• Personal Search Agents
• Technical challenges to this
• My idea: have distributed agents coupled with access to large, centralized indices.
• Most importantly: what is the big advantage??
• Need qualitative change in searching experience
• Interesting, but not shown useful yet
• My idea: have agents be pre-fetchers to automatically hunt for content for which you have a high probability of interest
• e.g. citation mining to collect all research papers within a particular domain

unintended techies

An article today in the New York Times discusses how more and more people (unsuprisingly in my view) are becoming technologically proficient by sheer necessity. The article includes some choice quotes from fellow PARC researchers.

Techies by Necessity, Not by Choice (requires free registration to read)

dive trip: 7/19-20

This past weekend I went on a diving trip to Monterey, getting in two dives on Saturday morning and two on Sunday morning. We spent our first dive out in the metridium fields, a garden of giant, white-plumed anemones that is situated fairly far out on the west side of San Carlos Beach (aka Breakwater), about 55 ft deep. The next dive we spent exploring the rocks of the Coast Guard pier. On Sunday we first headed out through a rich network of kelp forests (during which we surfaced and ran into a sea otter!), and then spent the second dive exploring the rocks of the pier again. I brought a disposable waterproof camera down with me and took a bunch of pictures. Hopefully at least some will turn out alright... I'll post any good ones once the film is developed. (btw the water was the coldest I have yet to experience in Monterey - as low as 46 degrees! My hands were about to fall off. yikes.)

In between dives on Saturday, we walked out on the Coast Guard pier (finding the fence unlocked) to check out all the sea lions lazing around on the rocks. We returned to find ourselves locked in, so had to ask a young lady to let us out. As we walked down the pier we talked to her and it turns out she works for a nature conservatory and told us some interesting facts about the migratory patterns of California sea lions. They start from the Channel Islands (off the coast of SoCal) and head up the coast way north, as far as Canada, before returning. She also made clear, for anyone interested, the distinction between seals and sea lions.

Seals as you can see, are paler in appearance, have no external ear flaps, and have very short pectoral fins.

The sea lions are browner in color, have external ear flaps, and have large pectoral fins.

Aren't you a better person for knowing that?

licensing linux?

SCO: Corporate Linux users must buy license. This will undoubtedly make SCO real popular with the open source community. Though their stock did rocket 11%, so there are definitely some happy folks out there. It remains to be seen how this will actually play out, but I don't like the look of it...

wozniak is back

Apple co-founder Steve Wozniak is back with a new startup called Wheels of Zeus (wOz), offering "wireless location-monitoring technology that would use electronic tags to help people keep track of their animals, children or property." Context-aware computing pushes that much closer to everyday life.

The New York Times is running an article, and Google News has plenty for interested individuals to read.

pharmacia

Must we really toy with someone's brain chemistry just to prevent them from calling for that set of Ginsu knives? I have a skeptical take on modern anti-depressants (or more accurately, on the motives of the pharmaceutical companies which produce them), and though I do understand and support their use when people are truly clinically depressed, this particular example seems ridiculous. I'd love to hear Aldous Huxley's take on this.

Drug Maker Looking to Treat Compulsive Shoppers

intellicide

The hyped-intelligence story continues to gain drama. British weapons advisor David Kelly disappeared Thursday and his dead body was discovered within a mile of his home on Friday. Police have confirmed that he died of a slit wrist, suggesting suicide (or, at least, the desired appearance of a suicide). This is after Kelly testified before Parliament and was identified as a possible media informant claiming that the British government hyped up its intelligence on Iraq to make war more attractive (Kelly had denied this). This is truly sad if an innocent man was driven to the edge by all this clamor. Still, feel free to post your own conspiracy theories...

UPDATE (7/21): The BBC has admitted that David Kelly was its source. There are still accusations, however, that BBC journalist Andrew Gilligan may have exaggerated Kelly's comments. The BBC and Andrew Gilligan deny this, of course. Not surprisingly, the BBC is running a host of stories on the issue. Meanwhile, Tony Blair has made it clear he will not be resigning in response to the tragedy.

UPDATE (9/18): Finally, Andrew Gilligan has admitted to hyping the story, and for unduly fingering Kelly as his source.

don't tread on me

A very inspiring Metallica hoax... if I can patent a I-IV-V progression, I'll be a millionaire within days.

Metallica Sues Over E, F Chords

The story even made it's way over to CNN.

but it tasted so sweet...

Great computer security article on SecurityFocus.com that passed through slashdot, which I'm posting here mainly as a reminder to myself to go back and read more articles in the series: Honeytokens: The Other Honeypot

intellinegligence

A new Salon article has more about the Veteran Intelligence Professionals for Sanity (VIPS), about whom I inquired earlier. The article claims they are made up of over 30 retired intelligence analysts, some highly decorated, from both the military and civilian sectors.

Read the article here.

Another interesting tidbit is the assertion by CIA director George Tenet that he was urged by the White House to include the questionable intelligence on a potential purchase of Nigerian uranium by Iraq. From the article: "On Thursday MSNBC quoted an anonymous source saying that Tenet "reluctantly" fingered National Security Council member Robert Joseph during the hearing. "

engrish as a second language

so bad it is good: www.engrish.com

and there's plenty more where this came from.

ha-ha-harvard

Will Ferrell's commencement speech at Harvard. Lucky stiffs. For my commencement at Berkeley, we got Janet Reno. Though to be fair, she was much funnier than you'd expect. But self-deprecation is easy when you're Janet Reno.

chastising cheney

The Veteran Intelligence Professionals for Sanity have written an open letter to President Bush about the faulty/forged intelligence used to convince Congress to allow the invasion of Iraq. In particular, they make strong accusations against Vice President Cheney and call for his ouster. Interesting.

Read the open letter at salon.com.

So who are the Veteran Intelligence Professionals for Sanity? They are cited as "a coast-to-coast enterprise; mostly intelligence officers from analysis side of CIA". I'm unable to find a web page for them, although they have written open letters to the President in the past. See the February 2003 memorandum written right after Powell's presentation to the UN, in which they agree that Iraq clearly violated UN resolution 1441, but claim that the probability of Iraq conducting an attack on the U.S. or selling weapons to terrorists is quite low. They seem to be all over progressive websites (Mother Jones, etc) today. And I'm sure Bush will be writing back to them promptly.

search (and destroy)

Yahoo! makes moves to acquire Overture, fueling it's growing search engine ambitions, while Google marches on and Microsoft is making "please-put-me-in-the-game-coach" faces on the sideline. Is there a search war a-brewing? And if so what will determine the victor? Read my extended entry for random musings on search engine competition and the next evolution of search engine technology: personalized search.

UPDATE (7/18): Here's a relevant Mercury News article with some more background: Search query returns reactions

Those of you who rank high on geekitude (if you need a metric, try the Geek Test - I scored 47.7%, making me an "Extreme Geek") already know that Yahoo!, still hot off its acquisition of Inktomi, is attempting to acquire Overture, who pioneered "pay-for-placement" search results and who earlier acquired AltaVista.

Strong currents are at work in the search engine world. While reigning champion and search engine super-hero Google continues it's strong march forward, Yahoo! is amassing it's own search engine super-powers. Meanwhile, in a dark cave in Redmond, Microsoft (or more precisely, the 50-member strong MSN search group) is gearing up to throw their hat into the ring. What does this mean? A showdown looms on the horizon.

But how would one hope to topple Google's page-ranking prowess? One avenue beyond leveraging the existing traffic and influence that Yahoo! and Microsoft (MSN) have would be to get the jump on the next technological advance in search technologies: personalized search.

When you enter a query at a search engine, it finds all the matching documents in the huge collections amassed by the engine's webcrawlers and then ranks them. What you see as a user are these results, presented in the order determined by this ranking. Part of Google's key to success was that its ranking mechanism, the now-famous PageRank algorithm (here's a research paper on it), exploits web hyperlink structure to identify authoritative pages on the web and rank them accordingly, creating results that you and I find much more relevant. Now imagine if such ranking mechanisms can be personalized for each and every user of the search engine. If the search engine has some knowledge of what your interests are (say, by reading in all your web bookmarks), it can tailor the result rankings to reflect those interests, resulting in search results that are that much more relevant to you.

One company has already tried this. Outride (formerly GroupFire) spun out of Xerox PARC (now PARC, Inc.) (actually, out of the very lab I work in!), with the goal of creating personalized search. Their technology was quite impressive, building off a number of PARC innovations, but they were in the right place at the wrong time. Sabotaged by the bursting dot-com bubble, and out in the market before search engine ranking performance reached the necessary threshold for robust, ubiquitous personalization, they failed to secure enough additional funding and had to shut their doors. As co-founder Jim Pitkow puts it, they were alternately "outridden" or "group-fired". Their assets (including all software and IP) were acquired by Google.

Fast forward to the present, where the clouds of search engine war may be starting to form. To achieve personalization, search engines will need to compute relevance rankings not once for the entire web (as currently done), but once per user for the entire web. Fortunately, students at Stanford's PageRank group have recently published papers on how to speed-up PageRank computation by using some clever linear algebra (remember Stanford has also birthed Google, and actually owns a fair chunk of them). Their resulting start-up company Kaltix (web page fairly bare, as they are in stealth mode) may indeed hold the key to making commercialized personalized web search a reality, which would make Kaltix the crown jewel in any search engine giant who may acquire them. Take your bets now.

And where am I in the midst of all this? Right in the middle it seems. The founder of Inktomi was my systems class professor, Outride was spun out of my own research group, multiple former Outride employees are now good friends of mine, and incidentally, one of the Kaltix founders is currently my housemate at my subletted summer residence. I'm excited to see what happens... I'll post more as things become fit for public consumption.

pixies reunion?

from the "i'll believe it when i see it" dept...

Frank Black Says Pixies Considering Reunion

though Francis suffers from none-too-surprising doubts: "I do dream about the Pixies reunion... It's like those schoolboy dreams when you don't do your homework and you don't study for the test, but I'm at the gig and we're hanging out, but it's an utter failure and I don't know the songs, and hardly anyone turns up for the gig and people walk out. That's what I'm afraid of, that it'd be a big, big failure."

if these doubts are conquered, this could be better than an eighteen minute orgasm. but if it does happen, then i say to you Messr. Black et al, with nothing but the sincerest love and respect, please please please do not mess this up.

howard and me

Of all the web hype regarding Howard Dean as of late, I found this article from Salon well worth the read. It describes Howard Dean's ideology and the demographic it resonates most strongly with. In the end, it draws parallels between Dean's campaign and the 1972 campaign of George McGovern, effectively labeling both as progressives ahead of their time - candidates who will decidedly lose the election, but whose platform and legacy will eventually go on the greater successes.

Interesting, sure, but what really got me was the description of Dean's favored demographic (paragraphs 4-6). This may be nothing new to many of you, but they really got my number. I've never seen my own (seemingly independently-reached) ideology and societal niche so precisely articulated and pigeon-holed. I guess I'm just one of the 15%. :) But if so, America's future may be a little brighter than I might have otherwise thought.

ubiquity?

I believe this originally passed through the metafilter before making it's way to me through a certain Jack Nicholson look-alike, but it's worth the redundancy:

http://www.brandrepublic.com/brandbulletin/showAd.cfm

A very vivid vision (enough annoying alliteration already) of context-aware / ubiquitous computing environments. Even though I do research in this space of technologies, I still find this pretty eerie... and it's not just due to this summer's string of the-computers-take-us-out films.

blog test

This is my blog. There are many others like it, but this one is mine. Thanks to metamanda and kwc for some design inspiration.

paper: animation support in a UI toolkit

Here's a back-post for a prelims paper: "Animation Support in a User Interface Toolkit", by Hudson and Stasko. I thought this paper particularly relevant, as I'm currently working in interactive graph visualization, which includes a heavy animation component. This paper got me considering higher level primitives I might use in the graph viz toolkit we are developing.

Animation Support in a User Interface Toolkit: Flexible, Robust, and Reusable Abstractions
Scott E. Hudson, John T. Stasko
UIST'93 (User Interface and Software Technology 1993)

In this paper, the authors present extensions to the Artkit user interface toolkit to support animation. The toolkit offers basic support for simple motion blur, "squash and stretch", use of arcing trajectories, controlled timing of actions, anticipation + follow-through, and slow-in / slow-out transitions. It also supports a robust scheduling system that helps deal with unpredictable performance from the windowing system... very important since this was running on X-Windows.

The main abstraction used is the transition, which consists of a pointer to the UI component that is moving, the trajectory the component will take, and the time interval over which to animate. The UI component can be any interactor object implemented in Artkit. The trajectory consists of the curve traveled (parameterized from 0 to 1) and a pacing function to determine velocities over the curve (e.g. using a line with slope 1 for uniform animation and an arctan or sigmoidal function to create slow-in / slow-out transitions). The times in the time interval can be expressed as absolute times, as a delay from the present time, or parameterized by the starting or ending of other transitions.

Robust animation and event-relative transitions are achieved using an animation dispatch agent. All that is assumed is that the tookit can ask what the current time is and that the window system will pass back control to the toolkit periodically. The agent constructs a scheduling queue of transitions, and attempts to estimate when the next draw cycle will appear on the screen using a measure of past updates. Using this redraw end time, the set of active transitions for the current cycle is selected. For each active transition, it is started or stopped as appropriate and current parameter values are passed through their pacing functions and mapped to screen positions using the trajectory.

This scheme will animate smoothly when the agent is given control at a regular intervals, but it will also properly handle delays, correctly delivering animation steps at larger intervals.

Criticism: The first thing that struck me is that no mention of scale is given. How many objects can I animate at once? What are the bottlenecks? Obviously rendering time is a major factor, but overhead is accrued through scheduling and through mapping each object through it's own pacing and transition items. In most cases I'd expect this to be a constant time overhead, but this isn't really discussed. Also, cool animated effects like squash and stretch was mentioned multiple times but the implementation of it is not discussed.

Today, 10 years later, we have incredibly more powerful processors and graphics cards, enabling much richer animation possibilities. This paper was ahead of it's time and today's popular toolkits - Swing, MFC, etc - are definitely behind the times. While toolkits like Java2D provide much of the rendering and geometric capabilities needed, animation managers like the kind presented here and in Xerox PARC's Information Visualizer are yet to be common. Hopefully as graphics power continues to grow and the drive for more powerful interactive technologies gains momentum (e.g. more widespread use of information visualization) these more powerful tools and abstractions will become commonplace.