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I'm currently working on a DPhil in HCT at the University of Sussex. This section of the website is for an on-going 'learning diary', for me to write my thoughts and notes on various courses and my thesis.


Seminar 2 - Feedback on Universal Usability research

Seminar 2 gave more of a clue to the way these are going to go in future. It was interesting. Talking around the topic of universal usability and what we found. But I'm not sure how I'm going to write up the seminars. The discussion was fairly free-ranging and without constantly writing things down (and not taking part) it was pretty hopeless to try and keep up. I have taken some really sketchy notes, and I'll try to reconstruct some of the stuff we went through, because it was interesting and may be useful to look back on.

The idea is that if we design for the 'average' user, we will discriminate against various groups. Conversely, if we design for the exceptional user we can come up with designs that are actually easier to use for everyone.

Guidelines are based on the sum of previous work and learnings in a given area, so the WCAG guidelines provide an overview of the research into accessibility before the guidelines were written.

We shouldn't limit accessibility to just sensible, work-related stuff. Why should fun be inaccessible? Of course, that causes some interesting problems. How do you translate a driving game into something that a blind person can play and enjoy? Multi-modal feedback can be very helpful, but there are still issues with understanding the model in the first place. (Mind you, Lizzie and I can't really get into shoot 'em ups, but a similar concept like throwing pies at someone is fine - how would that translate for a blind or someone with poor motor control?)

We covered into "skip to content" and how blind people like to start from the bottom of a webpage - ignoring all the headers and navigation junk at the top. Interesting that this transfers to the way that mobile browsing is going. An identification of the important stuff and present that first.

Look at youtube.com user geriatric1927 - older user getting to grips with a perceived 'young' technology.

Researchers include Ben Schneiderman as found previously, and also Jenny Preece and Yvonne Rogers. Better look them up too.

On top of individual researchers and academic organisations, worth looking into corporate ones. Xerox park and HP labs are good. Commercial pressure actually means that they may be ahead of the academic stuff.

Torches for blind people - translating space information to different modes of representation. (Haptic and sound.) Worth a look.

2 types of disability groups - those disabled from birth and those disabled after an incident or with degenerative conditions. They can have very different outlooks. Like a congenitally blind person asked to draw a table will draw something very different from someone who could see at some point. Colour concepts must be a bit the same.

Universal Usability Designing Computer Interfaces for Diverse Users. Worth a look as a book on the topic. See if the library's got it?

So yeah. That's what I've got. I'm sure we talked about lots more than that I've missed. But there we are.

I volunteered to lead next week's seminar, so I've got a paper to read and research. All good. Working with Yves. Just got to hope that he's allowed to stay on the course I guess!


Universal Usability

I did start looking at Julie Howell's page, but she focuses on website accessibility.

Universal Usability is more than just making online pages accessible once someone has the required technology. According to UniversalUsability.org  it is how to make information and communications services available to everyone. This includes things like supplying access to the services (initiatives such as the $100 laptop with the aim to supply access to children in 'developing' countries). It is not sufficient to simply provide access. The complexity of computer systems creates a need for instruction before effective use can take place. This highlights the accessibility and usability areas of research, and the need to create more intuitive, simple systems.

Ben Schneiderman keeps coming up. He opened the ACM conference on Universal Usability (November 16-17, 2000, Arlington, VA, USA) too. Keith Instone seems to run the UniversalUsability.org webpage, which came about as a result of the 2000 conference.

There have been two conferences on Universal Usability in 2000 and 2003. Surely due another one?  

Research areas

There are three main areas for research: technology variety (supporting a wide range of access devices), user diversity, and gaps in user knowledge (what the gaps are and how to bridge them).

Most work at the moment appears to be focused on web accessibility, which would appear to come under user diversity. Although I suppose the gaps in the user knowledge could be being bridged by making interfaces more intuitive to a degree. The challenges of mobile devices are being investigated to increase the range of access devices - driven mostly by the ubiquitous nature of the devices.  



Lecture 3 - Measuring light

Radiance (Watts) - the total amount of light emitted by a source in all wavelengths. For a 100W bulb, only 10-15W of the output is in the visible range. Someone asked about OLEDs. Which are apparently Organic Light Emitting Diodes. They seem to be very efficient, but a bit bleeding edge still at the moment. OLED-info.com has lots more information.

Luminance (Lumens) - the strength of light that is perceived by the human eye. Apparently the SI unit for this is the Candela...

Brightness - totally subjective. A measure of how bright an object appears to be.  


Lecture 3 - colour models

We didn't quite reach the end of lecture 2 in lecture 2, so I've got a bit to finish up on!

The HSV (hue, saturation and value) colour model (or hue saturation and brightness in Photoshop). 

We started looking at this last lecture, but we got a bit more detail on this one. 

Hue - based on human perception of the wavelength of the dominant colour. Psychophysical was the word used in the lecture, which apparently means involving the action or mutual relations of the physical and the psychical (in this case the stimulation of the cones by the light and the way it appears to us).

Saturation (or excitement purity) - a measure of the amount of white light. High saturation means bright colours and low white light content. Paul had a graphic of a graph with the visible light wavelengths on the x axis and the energy on the y axis. A highly saturated colour has a high level of energy at a given wavelength and low energy levels across all of the other wavelengths. As saturation decreases, the energy levels for all of the other wavelengths increase.

Brightness (value) - the perceived intensity of the light. This is very subjective. For example, the screen in the lecture theatre looked quite bright with the lights on, but when he dipped the lights the screen appeared to be brighter. In fact it had less light shining off it so it was less bright, but it appeared brighter in contrast to the rest of the room.


Why have different colour models? RGB seems to represent the light pretty well.

One reason is to simplify certain transformations. For example, to make a picture brighter in RGB would require all of the colour values to be changed individually. By representing in HSV we can change a single value across the entire picture.

Another reason is that it allows the data to be reduced to only 2 colour variables - hue and saturation. 

Apparently something called the YUV colour model is used in PAL TV systems, and YCBCR is used in digital televisions and jpegs. I didn't fully get this, so I'll do a little more reading and write something a bit more informative about it! But they are systems based on how humans see light, and separate out the luminance/chrominance bits. Humans see colour and intensity differently (back to the rods and cones). This means we can produce sharp colour images by overlaying a sharp black and white image with a very fuzzy colour component, and allows us to downsample the colour information.

YUV 4:2:2 is widely used, with the numbers reflecting the ratio of the components. If you take 4 pixels, each one would have a YUV component. Instead, we can send two of those pixels with YU information, and two with YV information. This means the information is stored in 8 bytes rather than 12.


Follow up on Lecture 2

I accidentally discovered while researching Allan Shepherd that cats have 2000 times the number of rods that humans do, owls have no cones at all, and chickens have no rods. Source: Allan Shepherd, "Curious Incidents in the garden at nighttime" (Centre for Alternative Technology 2005)

I have done some looking into the colour gamuts too, but I'm still not entirely comfortable with how they are generated. It seems to be a very mathematical process (which should make it better! Oh well...) that I'm not sure I actually need to know about. The wikipedia entries for colour gamut and  the CIE 1931 colour space give an overview, but as ever a certified source would be nice.