"I have a mind like a steel... uh... thingy." Patrick Logan's weblog.

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Saturday, October 30, 2004

Laser Shot to the Retina

Via Slashdot on Virtual Retina Displays from UW, potentially the future of displays for small devices (and aren't they all going to be small?)...

Furness is exploring a method to simplify the VRD and help bring costs down. His latest design dispenses with the mirror entirely. Instead, the tip of a single fiber-optic strand is pointed at the retina and mechanically bent back and forth at very high rates. Essentially, you're staring right down the beam instead of at its reflection. The stripped-down scanner, he says, may not only be less expensive to produce but also paints a prettier picture.

"We could make the image as big as we want and display a huge gamut of a colors," Furness says. "It would be like wearing an IMAX theater in a pair of eyeglasses."

Thursday, October 28, 2004

XML is *not* a Model

Uche Ogbuji writes in response to my remark about XML. Mainly he's concerned about the conflation of XML and WS*.

I would list something more serious... usage models. XML is just a notation. I agree WS* and XML are relatively distinct topics. But XML is used to represent everything from SOAP messages to config files to databases, and it's not particularly good at any of them.

What does it mean to perform an XML query, when XML is just a notation and not a model per se? There is no "there" there when it comes to what an XML model is. XML is a notation for expressing essentially *any* kind of model.

So worse than conflating XML and WS* is the notion that XML is a model of some kind.

Seminar: XML, RDF, Topic Maps, Relational Databases

Update - a comment from Manuel Simoni: Shawn Bower's thesis (PDF).

"XML, RDF, Topic Maps, Relational Databases: So many data models, so little time"

Lois Delcambre, PSU Computer Science / OGI
Monday, November 1, 2004, 12:00pm, FAB 10

One advantage of having different representation schemes and data models is that users can select the right representation and associated tools for their particular need. XML might be a great model to represent some of your information, but maybe sometimes you'd prefer to use RDF for some of your other data. The problem is that multiple representation schemes introduce structural, model-based heterogeneity, making it difficult to combine information from different sources and exploit information using generic tools (e.g., for querying or browsing).

In this work, we are interested in supporting multiple data models and representation schemes in a single, generic representation scheme. We have defined a meta-data-model based representation called the Uni-Level Description (ULD) with a novel architecture to overcome the limitations of typical meta-model based approaches. Unique features of the ULD include:

  • The ULD can accurately describe representation schemes, such as XML and RDF where schema is optional, in addition to traditional database models where a schema must be defined before any data can be entered.
  • The ULD permits data models that support multiple levels of schema or instance-of relationships.
  • The ULD represents the constructs of the data model, schema if present, and data in a single, uniform representation that can be easily used by generic tools.
We have used the ULD to write powerful, generic transformation rules that can even transform data directly from one representation scheme to another. We have also investigated the use of a simple generic browsing capability over information represented in diverse data models and representation schemes.

In this talk, we will motivate and define the ULD and discuss the transformation and browsing applications.

Lois Delcambre is a Professor of Computer Science at Portland State University. She also has a joint appointment as a Professor of Computer Science and Engineering with the OGI School of Science and Engineering at the Oregon Health & Science University. She works in the database field of computer science with a particular interest in database data models as well as other models for structured information including thesaurus models, knowledge representation models, semi-structured models such as XML and RDF, and ontology models.

System Debt

Daniel Hinz writes from OOPSLA on the conference Wiki...

I think the concept of software debt is becoming an increasingly important concept. My experience indicates that way too many developers have a very short idea of the future. They move on often enough that they have no notion of interest coming due.

Wednesday, October 27, 2004

The Why of XML

James Robertson writes about XML's ubiquity and yet lameness as a notation for configuration.

On the other hand "ini" files are equally lame, being too simplistic. And so we have a simple yet more expressive alternative in YAML which serves as a reasonable data notation that is printable, efficient, readable, streamable, maps well to popular dynamic languages, and so on... several things that XML is not.

Tuesday, October 26, 2004

As I Suspected

From Greg Vaughn at OOPSLA 2004...

Another topic I’m seeing in various places, tutorials, practitioner reports, etc., is an analysis of what Architecture really is. One tongue in cheek definition given by Douglas Schmidt at a tutorial about the Forgotten Craft of Software Architecture is that architects are those people whose development skills are too oudated to still be developers, but don’t look good enough in suits to be managers.

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About Me

Portland, Oregon, United States
I'm usually writing from my favorite location on the planet, the pacific northwest of the u.s. I write for myself only and unless otherwise specified my posts here should not be taken as representing an official position of my employer. Contact me at my gee mail account, username patrickdlogan.