Monthly Archives: April 2014

Fun Tech Stuff: Going Under the Hood with XML

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Here’s the complete series of related posts (in order) on going under the hood with XML and its uses in learning technologies. Click on each to see the full post.

An LMS, or Learning Management System is a software application that provides a framework for the course material, and takes care of all the back-end administration that is necessary to make the learning experience happen.

SCORM stands for “Sharable Content Object Reference Model,” and is a set of technical standards that define how Web-based online learning content and LMSs communicate with each other.

The Tin Can application programming interface, or API, (also known as The Experience API or xAPI) is the next generation of SCORM. It can capture formal as well as informal and social learning and performance as it actually happens, inside our outside an LMS or Web environment.

Metadata is information about information, typically describing a data resource (e.g., a Web page, an image, a document, an e-learning module, an ebook) by specifying information about it (e.g., creation, purpose, structure) to provide context and improve meaning, and help evolve the semantic Web.

XML is the workhorse of metadata and the semantic Web, the means by which we describe the meaning and context of information on the Web. XML stands for eXtensible Markup Language. It pops up all over the place, specifying contents and navigation in elearning, in ebooks, and on the Web.

Here are examples of the use of XML in SCORM and XML in eBooks.

XML Part 3: Ebook Example

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This is last in a series of related posts on Fun Tech Stuff going under the hood with XML and its uses in learning technologies: Learning Management Systems, SCORM, Tin Can, Metadata, and XML, as well as examples of XML in SCORM and XML in eBooks.

Most ebooks, including the Kindle (with minor proprietary variations), are based on the open, XML-based EPUB standard. And what does an EPUB ebook look like on the inside? Believe it or not, it is essentially a zip file. And if you unzip it, you will find a folder with a whole set of other files and folders filled with XML files, XHTML files (a stricter version of HTML), image files, and maybe even sound and video files. All these files are stitched together—you guessed it—through the magic of XML, doing it’s semantic job of providing meaning and context to all that surround it.

One of the key files in an ebook is the content.opf file. It tells the ebook reader (e.g., your iPad or Kindle) what the book is, and how to navigate through it.

Let’s take a peek inside.

1. Yay! The file starts with a line that identifies it as an xml file.

2. The next line defines it as a package file, as defined by the Open Packaging Format bit of the EPUB standard.

3. Next comes the metatada section. Notice the “dc:”? That refers to the Dublin Core metadata standard discussed in our previous Metadata post.

4. Next comes the manifest, with its list of all the files that make up the ebook.

5. Finally comes the spine, which tells your ereader the order in which the content should be presented.

content-opf

And those are just a few of the ways in which XML helps people and computers work more closely together to improve the meaning and the context of information.

XML Part 2: SCORM Example

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This is next in a series of related posts on Fun Tech Stuff going under the hood with XML and its uses in learning technologies: Learning Management Systems, SCORM, Tin Can, Metadata, and XML, as well as examples of XML in SCORM and XML in eBooks.

As you recall from our previous post, SCORM is a set of technical standards that define how Web-based online learning content and LMSs communicate with each other. SCORM is composed of three sub-specifications, one of which is the content packaging section, which contains an XML file called imsmanifest.xml. The XML manifest file describes how the parts of the course are organized, and lists the associated resources.

Note the following in the example below:

1. The file starts with a line that identifies it as an xml file.

2. The next line defines it as a manifest file (i.e., a file that lists contents).

3. Next comes the metadata tag, describing the list as part of the SCORM standard, version 1.2.

4-5. What follows is the heart of the manifest, defining the learning module items and their titles, and the related resources (e.g., files).

imsmanifest

Thanks to the imsmanifest file and rest of the information defined in SCORM’s XML files and APIs, any LMS that supports the SCORM standard can successfully store, display, and track any Web-based online learning content written to the same standard. The metadata in the XML files discloses the meaning and context of the information in the elearning modules, and the LMS processes it as appropriate.

In our next post, we’ll look at one more example of how XML is used to create the metadata that describes the meaning and context of information, this time in an ebook.

 

XML Part I: Markup Language

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This is next in a series of related posts on Fun Tech Stuff going under the hood with XML and its uses in learning technologies: Learning Management Systems, SCORM, Tin Can, Metadata, and XML, as well as examples of XML in SCORM and XML in eBooks.

XML is the workhorse of metadata and the semantic Web, the means by which we describe the meaning and context of information on the Web. XML stands for eXtensible Markup Language. It pops up all over the place, specifying contents and navigation in elearning, in ebooks, and on the Web.

XML is a markup language much like HTML (HyperText Markup Language), the language we use to display the words, pictures, sounds, and video that make up the Web.

Markup Languages

What is a markup language? It is a system of rules and hidden tags (i.e., labels) that let us define how data can be stored, displayed, or processed. It is quite powerful but quite simple in structure. It’s based on plain text and designed to be readable by both humans and machines.

Here’s a simple example of HTML markup.

Let’s say you want your Web page to display a heading and a few short paragraphs. You want it to say this:

html example

So you would mark it up as follows, using angle brackets (< >) and tags to tell the browser how you’d like the text displayed:

<H1>Hopeless Optimist</H1>

<p>Being a hopeless optimist, I think the Chicago White Sox are going to win the World Series this year! People may laugh, but I have hope. </p>

<p>That is the meaning of being an optimist. </p>

As you can see, this is not rocket science! The <H1> tag indicates where the heading should start, and the </H1> indicates where the heading should end. Likewise, the <p> and </p> tags indicate where the paragraphs should start and end.

The basic scheme is as follows:

< tag>
…
< / end tag>

Of course there are lots of tags, and lots of complexity in how those tags can be used and nested, but the underlying scheme is straightforward.

HTML and XML

HTML and XML are similar in nature, both being markup languages, but they have a couple of key differences.

First, HTML is designed to tell Web browsers how to display data; it’s all about marking up text and other assets like images, sound, and video, so the browser knows how to format it: make it a heading, make it bold, put it in a table, turn it into bullet points, make it so tall or so wide, break a paragraph, skip a line. Second, the tags you use to mark up your words and pictures are all predefined; you have to use the right tags if you want to get the right result. If you said:

<Heading1>Hopeless Optimist</Heading1>

instead of:

<H1>Hopeless Optimist</H1>

the browser wouldn’t know what you were talking about, and would not display your heading correctly. HTML is an open standard. And while it is constantly evolving, it is well known to both Web developers and browser developers, so generally what we code is rendered properly.

XML, on the other hand, is not designed to display data, it’s designed to provide meaning and context for data, so the markup is used to do that.

Meaning and Context

In our previous Metadata post, we gave an example of a person using a Web site that contains a monument’s latitude and longitude so that person can locate the monument while walking through a park. The latitude and longitude would be defined in the Web site with XML tags that might look something like this:

<geo:Point>
<geo:lat>41.882406</geo:lat>
<geo:long> -87.62382 </geo:long>
</geo:Point>

XML provides meaning and context for data, and provides it using plain text, so it can be easily written and read by any application (as well as by people).

Not Predefined

Also, XML tags are not predefined; you or an outside organization can define the meaning of the tag and link to its definition. The meaning and context of the data is conveyed both by the tag itself and by the linked definition of the tag, called an XML Name Space (xmlns).

< … xmlns:geo=”http://www.w3.org/ …>

Tags define the data, and name spaces define the tags:

xml tags and name space

Of course the point is not to learn how to code XML, but to understand its power, and how it is used under the hood in Web sites, in e-learning delivery (e.g., SCORM), and in ebooks, all of which are key to the future of learning.

In the next two posts, we’ll look at a couple of examples of how XML is used, first in SCORM, and then in an ebook, to create the metadata that describe the meaning and context of that information.