background preloader

The Semantic Web: An Introduction

The Semantic Web: An Introduction
This document is designed as being a simple but comprehensive introductory publication for anybody trying to get into the Semantic Web: from beginners through to long time hackers. Recommended pre-reading: the Semantic Web in Breadth. Table Of Contents What Is The Semantic Web? The Semantic Web is a mesh of information linked up in such a way as to be easily processable by machines, on a global scale. You can think of it as being an efficient way of representing data on the World Wide Web, or as a globally linked database. The Semantic Web was thought up by Tim Berners-Lee, inventor of the WWW, URIs, HTTP, and HTML. What's the rationale for such a system? So the Semantic Web can be seen as a huge engineering solution... but it is more than that. URI - Uniform Resource Identifier A URI is simply a Web identifier: like the strings starting with "http:" or "ftp:" that you often find on the World Wide Web. RDF - Resource Description Framework A triple can simply be described as three URIs. Logic Related:  RDF & the Semantic Web

RDF - Semantic Web Standards Overview RDF is a standard model for data interchange on the Web. RDF has features that facilitate data merging even if the underlying schemas differ, and it specifically supports the evolution of schemas over time without requiring all the data consumers to be changed. RDF extends the linking structure of the Web to use URIs to name the relationship between things as well as the two ends of the link (this is usually referred to as a “triple”). This linking structure forms a directed, labeled graph, where the edges represent the named link between two resources, represented by the graph nodes. Recommended Reading The RDF 1.1 specification consists of a suite of W3C Recommendations and Working Group Notes, published in 2014. A number of textbooks have been published on RDF and on Semantic Web in general. Discussions on a possible next version of RDF W3C has recently set up a new RDF Working Group, whose charter is to make a minor revision of RDF. Last modified and/or added All relevant tools

Clojure for the Semantic Web - Digital Digressions by Stuart Sie I dropped in to hear Rich Hickey talk about Clojure at the New York Semantic Web meetup group. Some highlights: • Some programs, like compilers or theorem provers, are themselves functions. They take input and produce output. Purely functional languages like Haskell are good for these kinds of programs. • Most Clojure programmers go through an arc. • Rich recommended a paper, Out of the Tar Pit, for a discussion of functional and relational techniques to manage state. • Clojure’s data structures are persistent. • The first thing Rich did when experimenting with the semantic web was to pull data out of the Jena API and get it into Clojure data structures. Screencasts and code from the talk should appear soon — watch clojure.org or the Clojure Google group for an announcement.

URL vs. URI vs. URN: The Confusion Continues A year has passsed since my last post on URIs and URLs and it would seem that some of the concepts are still lost on some folks. With that said, I figured I’d throw up another post that I could try and address some of the questions raised in the comments of both posts. URLs and URNs are both URIs This is one point that can’t be stated enough. Examples of URLs and URNs: People have also suggested that these posts could have been more helpful if I had provided some examples that illustrate the difference between a URL and a URI. Again, all of the examples above are all valid examples of URIs. There’s a very informative page by Tim Berners-Lee that provides a lot of good deails on Uniform Resource Identifiers. “The only thing you can use an identifier for is to refer to an object. When you followed the link to this page, you didn’t have to do anything other than clicking it. Can we say that:“ No. Another commenter also asserted the following:

What is the Semantic Web? Introduction Many people are not clear as to what the Semantic web is, and as we are the Semantic Web Agreement Group, we need to define it for people. Therefore, here is an attempt at a clear view of the Semantic Web:- The Semantic Web is a Web that includes documents, or portions of documents, describing explicit relationships between things and containing semantic information intended for automated processing by our machines. It operates on the principle of shared data. Clear Intent Although the SW is a Web of data, it is intended primarily for humans; it would use machine processing and databases to take away some of the burdens we currently face so that we can concentrate on the more important things that we can use the Web for. Practical solutions include the use of XSLT to derive RDF from XML sources, the work on topic maps and RDF convergence, the emergence of general-purpose RDF databases and engines, and general and specific GUIs for RDF data. - XML.com An Example Data:- Filter:-

RelFinder - Visual Data Web Are you interested in how things are related with each other? The RelFinder helps to get an overview: It extracts and visualizes relationships between given objects in RDF data and makes these relationships interactively explorable. Highlighting and filtering features support visual analysis both on a global and detailed level. The RelFinder is based on the open source framework Adobe Flex, easy-to-use and works with any RDF dataset that provides standardized SPARQL access. Check out the following links for some examples: The RelFinder can easily be configured to work with different RDF datasets. The RelFinder can also be more deeply integrated with your project: Integrating the RelFinder See the following examples of how the RelFinder is integrated into other projects: Ontotext applies the RelFinder to enable an exploration of relationships in the biomedical domain. All tools on this website are research prototypes that might contain errors.

RDFizers RDFizers glossary definition:=The RDFizer project is directory of tools for converting various data formats into RDF. In addition we provide a home for some of these tools. What can I do with these? You can have a computer generate the RDF representation of your data for you, instead of you doing it by hand. Why were they built? Writing RDF by hand can be a very time consuming and error prone experience, but the Semantic Web suffers from the chicken-egg problem that no killer app will be written without enough data and no data will be exposed without the benefit of a killer app that uses it. This is one of our solutions to unlocking the catch-22: identify existing datasets that could be of potential interest and write tools that can capture at least a little bit of those data structures. What do you mean by "converting into RDF"? Each of the RDFizers tries to be as specific as possible in identifying the semantics associated with the data that is being converted. See also

Guide to the semantic web Heart Attack: Detecting Heartbleed Exploits in Real-Time The OpenSSL Heartbleed vulnerability is proving to be one of the bigger vulnerabilities the security community has seen. As vendors and administrators scramble to patch their systems and users struggle to identify what sites are safe to use, hackers are taking full advantage of the vulnerability. Tripwire’s VERT team has quickly deployed the most robust coverage for detecting the vulnerability through IP360, PureCloud and SecureScan. What if we also want to monitor and be able to identify when the exploit is being used against us? Using a combination of an IDS and Tripwire Log Center allows us to do just that. Heartbleed & Honeypot There are several versions of the Heartbleed exploit actively in the wild, some are simply being used to test if systems are vulnerable, as well as more robust versions available in Metasploit and other frameworks. Successful Heartbleed Exploit Attempt I can now easily act on these alerts and correlate them to other events in my environment. Related Articles:

Related:  decioweybertijuniorGaddgetsArticles