Category Archives: web development

Italian conferences: PPD10, AVI2010 and Search Computing

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I got back from trip to Rome and Milan last Tuesday, this included the PPD10 workshop that Aaron, Lucia, Sri and I had organised, and the AVI 2008 conference, both in University of Rome “La Sapienza”, and a day workshop on Search Computing at Milan Polytechnic.

PPD10

The PPD10 workshop on Coupled Display Visual Interfaces1 followed on from a previous event, PPD08 at AVI 2008 and also a workshop on “Designing And Evaluating Mobile Phone-Based Interaction With Public Displays” at CHI2008.  The linking of public and private displays is something I’ve been interested in for some years and it was exciting to see some of the kinds of scenarios discussed at Lancaster as potential futures some years ago now being implemented over a range of technologies.  Many of the key issues and problems proposed then are still to be resolved and new ones arising, but certainly it seems the technology is ‘coming of age’.  As well as much work filling in the space of interactions, there were also papers that pushed some of the existing dimensions/classifications, in particular, Rasmus Gude’s paper on “Digital Hospitality” stretched the public/private dimension by considering the appropriation of technology in the home by house guests.  The full proceedings are available at the PPD10 website.

AVI 2010

AVI is always a joy, and AVI 2010 no exception; a biennial, single-track conference with high-quality papers (20% accept rate this year), and always in lovely places in Italy with good food and good company!  I first went to AVI in 1996 when it was in Gubbio to give a keynote “Closing the Loop: modelling action, perception and information“, and have gone every time since — I always say that Stefano Levialdi is a bit like a drug pusher, the first experience for free and ever after you are hooked! The high spot this year was undoubtedly Hitomi Tsujita‘s “Complete fashion coordinator”2, a system for using social networking to help choose clothes to wear — partly just fun with a wonderful video, but also a very thoughtful mix of physical and digital technology.


images from Complete Fashion Coordinator

The keynotes were all great, Daniel Keim gave a really lucid state of the art in Visual Analytics (more later) and Patrick Lynch a fresh view of visual understanding based on many years experience and highlighting particularly on some of the more immediate ‘gut’ reactions we have to interfaces.  Daniel Wigdor gave an almost blow-by-blow account of work at Microsoft on developing interaction methods for next-generation touch-based user interfaces.  His paper is a great methodological exemplar for researchers combining very practical considerations, more principled design space analysis and targeted experimentation.

Looking more at the detail of Daniel’s work at Microsoft, it is interesting that he has a harder job than Apple’s interaction developers.  While Apple can design the hardware and interaction together, MS as system providers need to deal with very diverse hardware, leading to a ‘least common denominator’ approach at the level of quite basic touch interactions.  For walk-up-and use systems such as Microsoft Surface in bar tables, this means that users have a consistent experience across devices.  However, I did wonder whether this approach which is basically the presentation/lexical level of Seeheim was best, or whether it would be better to settle at some higher-level primitives more at the Seeheim dialog level, thinking particularly of the way the iPhone turns pull down menus form web pages into spinning selectors.  For devices that people own it maybe that these more device specific variants of common logical interactions allow a richer user experience.

The complete AVI 2010 proceedings (in colour or B&W) can be found at the conference website.

The very last session of AVI was a panel I chaired on “Visual Analytics: people at the heart of data” with Daniel Keim, Margit Pohl, Bob Spence and Enrico Bertini (in the order they sat at the table!).  The panel was prompted largely because the EU VisMaster Coordinated Action is producing a roadmap document looking at future challenges for visual analytics research in Europe and elsewhere.  I had been worried that it could be a bit dead at 5pm on the last day of the conference, but it was a lively discussion … and Bob served well as the enthusiastic but also slightly sceptical outsider to VisMaster!

As I write this, there is still time (just, literally weeks!) for final input into the VisMaster roadmap and if you would like a draft I’ll be happy to send you a PDF and even happier if you give some feedback 🙂

Search Computing

I was invited to go to this one-day workshop and had the joy to travel up on the train from Rome with Stu Card and his daughter Gwyneth.

The search computing workshop was organised by the SeCo project. This is a large single-site project (around 25 people for 5 years) funded as one of the EU’s ‘IDEAS Advanced Grants’ supporting ‘investigation-driven frontier research’.  Really good to see the EU funding work at the bleeding edge as so many national and European projects end up being ‘safe’.

The term search computing was entirely new to me, although instantly brought several concepts to mind.  In fact the principle focus of SeCo is the bringing together of information in deep web resources including combining result rankings; in database terms a form of distributed join over heterogeneous data sources.

The work had many personal connections including work on concept classification using ODP data dating back to aQtive days as well as onCue itself and Snip!t.  It also has similarities with linked data in the semantic web word, however with crucial differences.  SeCo’s service approach uses meta-descriptions of the services to add semantics, whereas linked data in principle includes a degree of semantics in the RDF data.  Also the ‘join’ on services is on values and so uses a degree of run-time identity matching (Stu Card’s example was how to know that LA=’Los Angeles’), whereas linked data relies on URIs so (again in principle) matching has already been done during data preparation.  My feeling is that the linking of the two paradigms would be very powerful, and even for certain kinds of raw data, such as tables, external semantics seems sensible.

One of the real opportunities for both is to harness user interaction with data as an extra source of semantics.  For example, for the identity matching issue, if a user is linking two data sources and notices that ‘LA’ and ‘Los Angeles’ are not identified, this can be added as part of the interaction to serve the user’s own purposes at that time, but by so doing adding a special case that can be used for the benefit of future users.

While SeCo is predominantly focused on the search federation, the broader issue of using search as part of algorithmics is also fascinating.  Traditional algorithmics assumes that knowledge is basically in code or rules and is applied to data.  In contrast we are seeing the rise of web algorithmics where knowledge is garnered from vast volumes of data.  For example, Gianluca Demartini at the workshop mentioned that his group had used the Google suggest API to extend keywords and I’ve seen the same trick used previously3.  To some extent this is like classic techniques of information retrieval, but whereas IR is principally focused on a closed document set, here the document set is being used to establish knowledge that can be used elsewhere.  In work I’ve been involved with, both the concept classification and folksonomy mining with Alessio apply this same broad principle.

The slides from the workshop are appearing (but not all there yet!) at the workshop web page on the SeCo site.

  1. yes I know this doesn’t give ‘PPD’ this stands for “public and private displays”[back]
  2. Hitomi Tsujita, Koji Tsukada, Keisuke Kambara, Itiro Siio, Complete Fashion Coordinator: A support system for capturing and selecting daily clothes with social network, Proceedings of the Working Conference on Advanced Visual Interfaces (AVI2010), pp.127–132.[back]
  3. The Yahoo! Related Suggestions API offers a similar service.[back]

names – a file by any other name

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Naming things seems relatively unproblematic until you try to do it — ask any couple with a baby on the way.  Naming files is no easier.

Earlier today Fiona @lovefibre was using the MAC OS Time Machine to retrieve an old version of a file (let’s call it “fisfile.doc”).  She wanted to extract a part that she knew she had deleted in order to use in the current version.  Of course the file you are retrieving has the same name as the current file, and the default is to overwrite the current version; that is a simple backup restore.  However, you can ask Time Machine to retain both versions; at which point you end up with two files called, for example, “fisfile.doc” and “fisfile-original.doc”.  In this case ‘original’ means ‘the most recent version’ and the unlabelled one is the old version you have just restored.  This was not  too confusing, but personally I would have been tempted to call the restored file something like “fisfile-2010-01-17-10-33.doc”, in particular because one wonders what will happen if you try to restore several copies of the same file to work on, for example, to work out when an error slipped into a document.

OK, just an single incident, but only a few minutes later I had another example of problematic naming.

Continue reading →

Recognition vs classification

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While putting away the cutlery I noticed that I always do it one kind at a time: all the knives, then all the forks, etc. While this may simply be a sign of an obsessive personality, I realised there was a general psychological principle at work here.

We often make the distinction between recognition and recall and know, as interface designers, that the former is easier, especially for infrequently used features, e.g. menus rather than commands.

In the cutlery tray task the trade-off is between a classification task “here is an item what kind is it?” versus a visual recognition one “where is the next knife”. The former requires a level of mental processing and is subject to Hick’s law, whereas the latter depends purely on lower level visual processing, a pop-out effect.

I am wondering whether this has user interface equivalents. I am thinking about times when one is sorting things: bookmarks, photos, even my own snip!t. Sometimes you work by classification: select an item, then choose where to put it; for others you choose a category (or an album) and then select what to put in it. Here the ‘recognition’ task is more complex and not just visual, but I wonder if the same principle applies?

Sounds like a good dissertation project!

reading barcodes on the iPhone

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I was wondering about scanning barcodes using the iPhone and found that pic2shop (a free app) lets third part iPhone apps and even web pages access its scanning software through a simply URL scheme interface.

Their developer documentation has an example iPhone app, but not an example web page.  However, I made a web page using their interface in about 5 minutes (see PHP source of barcode reader).

If you have an iPhone you can try it out and scan a bar code now, although you need to install pic2shop first (but it is free).

By allowing third party apps to use their software they encourage downloads of their app, which will bring them revenue through product purchases.  Through free giving they bring themselves benefit; a good open access story.

Apple’s Model-View-Controller is Seeheim

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Just reading the iPhone Cocoa developer docs and its description of Model-View-Controller. However, if you look at the diagram rather than the model component directly notifying the view of changes as in classic MVC, in Cocoa the controller acts as mediator, more like the Dialogue component in the Seeheim architecture1 or the Control component in PAC.

MVC from Mac Cocoa development docs

The docs describing the Cocoa MVC design pattern in more detail in fact do a detailed comparison with the Smalltalk MVC, but do not refer to Seeheim or PAC, I guess because they are less well known now-a-days.  Only a few weeks ago when discussing architecture with my students, I described Seeheim as being more a conceptual architecture and not used in actual implementations now.  I will have to update my lectures – Seeheim lives!

  1. Shocked to find no real web documentation for Seeheim, not even on Wikipedia; looks like CS memory is short.  However, it is described in chapter 8 of the HCI book and in the chapter 8 slides[back]

big file?

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Encountered the following when downloading a file for proof checking from the Elsevier “E-Proofing” System web site1.  Happily it turned out to be a mere 950 K not a gigabyte!

  1. I was going to add a link to the system web site itself at http://elsevier.sps.co.in/ but instead of some sort of home page you get redirected to the proofs of someone’s article in the Journal of Computational Physics![back]

data types and interpretation in RDF

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After following a link from one of Nad’s tweets, read Jeni Tennison’s “SPARQL & Visualisation Frustrations: RDF Datatyping“.  Jeni had been having problems processing RDF of MP’s expense claims, because the amounts were plain RDF strings rather than as typed numbers.  She  suggests some best practice rules for data types in RDF based on the underlying philosophy of RDF that it should be self-describing:

  • if the literal is XML, it should be an XML literal
  • if the literal is in a particular language (such as a description or a name), it should be a plain literal with that language
  • otherwise it should be given an appropriate datatype

These seem pretty sensible for simple data types.

In work on the TIM project with colleagues in Athens and Rome, we too had issues with representing data types in ontologies, but more to do with the status of a data type.  Is a date a single thing “2009-08-03T10:23+01:00″, or is it a compound [[date year=”2009″ month=”8” …]]?

I just took a quick peek at how Dublin Core handles dates and see that the closest to standard references1 still include dates as ‘bare’ strings with implied semantics only, although one of the most recent docs does say:

“It is recommended that RDF applications use explicit rdf:type triples …”

and David MComb’s “An OWL version of the Dublin Core” gives an alternative OWL ontology for DC that does include an explicit type for dc:date:

<owl:DatatypeProperty rdf:about="#date">
  <rdfs:domain rdf:resource="#Document"/>
  <rdfs:range rdf:resource="http://www.w3.org/2001/XMLSchema#dateTime"/>
</owl:DatatypeProperty>

Our solution to the compound types has been to have “value classes” which do not represent ‘things’ in the world, similar to the way the RDF for vcard represents  complex elements such as names using blank nodes:

<vCard:N rdf:parseType="Resource">
  <vCard:Family> Crystal </vCard:Family>
  <vCard:Given> Corky </vCard:Given>
  ...
</vCard:N>

From2

This is fine, and we can have rules for parsing and formatting dates as compound objects to and from, say, W3C datetime strings.  However, this conflicts with the desire to have self-describing RDF as these formatting and parsing rules have to be available to any application or be present as reasoning rules in RDF stores.  If Jeni had been trying to use RDF data coded like this she would be cursing us!

This tension between representations of things (dates, names) and more semantic descriptions is also evident in other areas.  Looking again at Dublin Core the metamodal allows a property such as “subject”  to have a complex object with a URI and possibly several string values.

Very semantic, but hardly mashes well with sources that just say <dc:subject>Biology</dc:subject>.  Again a reasoning store could infer one from the other, but we still have issues about where the knowledge for such transformations resides.

Part of the problem is that the ‘self-describing’ nature of RDF is a bit illusary.   In (Piercian) semiotics the interpretant of a sign is crucial, representations are interpreted by an agent in a particular context assuming a particular language, etc.  We do not expect human language to be ‘sef describing’ in the sense of being totally acontextual.  Similarly in philosophy words and ideas are treated as intentional, in the (not standard English) sense that they refer out to something else; however, the binding of the idea to the thing it refers to is not part of the word, but separate from it.  Effectively the desire to be self-describing runs the risk of ignoring this distinction3.

Leigh Dodds commented on Jeni’s post to explain that the reason the expense amounts were not numbers was that some were published in non-standard ways such as “12345 (2004)”.  As an example this captures succinctly the perpetual problem between representation and abstracted meaning.  If a journal article was printed in the “Autumn 2007” issue of  quarterly magazine, do we express this as <dc:date>2007</dc:date> or <dc:date>2007-10-01</dc:date>  attempting to give an approximation or inference from the actual represented date.

This makes one wonder whether what is really needed here is a meta-description of the RDF source (not simply the OWL as one wants to talk about the use of dc:date or whatever in a particular context) that can say things like “mainly numbers, but also occasionally non-strandard forms”, or “amounts sometimes refer to different years”.  Of course to be machine mashable there would need to be an ontology for such annotation …

  1. see “Expressing Simple Dublin Core in RDF/XML“, “Expressing Dublin Core metadata using HTML/XHTML meta and link elements” and Stanford DC OWL[back]
  2. Renato Iannella, Representing vCard Objects in RDF/XML, W3C Note, 22 February 2001.[back]
  3. Doing a quick web seek, these issues are discussed in several places, for example: Glaser, H., Lewy, T., Millard, I. and Dowling, B. (2007) On Coreference and the Semantic Web, (Technical Report, Electronics & Computer Science, University of Southampton) and Legg, C. (2007). Peirce, meaning and the semantic web (Paper presented at Applying Peirce Conference, University of Helsinki, Finland, June 2007). [back]

the more things change …

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I’ve been reading Jeni (Tennison)’s Musings about techie web stuff XML, RDF, etc.  Two articles particularly caught my eye.  One was Versioning URIs about URIs for real world and conceptual objects (schools, towns), and in particular how to deal with the fact that these change over time.  The other was Working With Fragmented Overlapping Markup all about managing multiple hierarchies of structure for the same underlying data.

In the past I’ve studied issues both of versioning and of multiple structures on the same data1, and Jeni lays out the issues for both really clearly. However, both topics gave a sense of deja vu, not just because of my own work, but because they reminded me of similar issues that go way back before the web was even thought of.

Versioning URIs and unique identifiers2

In my very first computing job (COBOL programming for Cumbria County Council) many many years ago, I read an article in Computer Weekly about choice of keys (I think for ISAM not even relational DBs). The article argued that keys should NEVER contain anything informational as it is bound to change. The author gave an example of standard maritime identifiers for a ship’s journey (rather like a flight number) that were based on destination port and supposed to never change … except when the ship maybe moved to a different route. There is always an ‘except’, so, the author argued, keys should be non-informational.

Just a short while after reading this I was working on a personnel system for the Education Dept. and was told emphatically that every teacher had a DES code given to them by government and that this code never changed. I believed them … they were my clients. However, sure enough, after several rounds of testing and demoing when they were happy with everything I tried a first mass import from the council’s main payroll file. Validations failed on a number of the DES numbers. It turned out that every teacher had a DES number except for new teachers where the Education Dept. then issued a sort of ‘pretend’ one … and of course the DES number never changed except when the real number came through. Of course, the uniqueness of the key was core to lots of the system … major rewrite :-/

The same issues occurred in many relational DBs where the spirit (rather like RDF triples) was that the record was defined by values, not by identity … but look at most SQL DBs today and everywhere you see unique but arbitrary identifying ids. DOIs, ISBNs, the BBC programme ids – we relearn the old lessons.

Unfortunately, once one leaves the engineered world of databases or SemWeb, neither arbitrary ids nor versioned ones entirely solve things as many real world entities tend to evolve rather than metamorphose, so for many purposes http://persons.org/2009/AlanDix is the same as http://persons.org/1969/AlanDix, but for others different: ‘nearly same as’ only has limited transitivity!

  1. e.g. Modelling Versions in Collaborative Work and Collaboration on different document processing platforms; quite a few years ago now![back]
  2. edited version of comments I left on Jeni’s post[back]

fix for WordPress shortcode bug

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I’m starting to use shortcodes heavily in WordPress1 as we are using it internally on the DEPtH project to coordinate our new TouchIT book.  There was minor bug which meant that HTML tags came out unbalanced (e.g. “<p></div></p”).

I’ve just been fixing it and posting a patch2, interestingly the bug was partly due to the fact that back-references in regular expressions count from the beginning of the regular expression, making it impossible to use them if the expression may be ‘glued’ into a larger one … lack of referential transparency!

For anyone having similar problems, full details and patch below (all WP and PHP techie stuff).

Continue reading →

  1. see section “using dynamic binding” in What’s wrong with dynamic binding?[back]
  2. TRAC ticket #10490[back]