The History Of The Semantic Web

Published Date: 02 Nov 2017

ABSTRACT

"The Semantic Web brings to the Web the idea of having data defined and linked in away that it can be used for more effective discovery, automation, integration and reuse across applications."

The Semantic Web provides a way to encode information and knowledge on web pages in a form that is easier for computers to understand and process. Its continuous evolution of the Internet has opened unimaginable opportunities and challenges on the web. The development of the Semantic Web has been a long running project championed by the inventor of the web, Sir Tim Berners-Lee. It is built around his concept of the ‘Web of data’ which means moving on from the existing document centric view of the Web to a data centric one. In this vision of the Web, data and the relationships between data are key. Coupled with these ongoing Semantic Web developments there has also been growing interest in the related areas of linked and open data. Today's Web is composed primarily of unstructured data, such as HTML pages. HTML pages can be searched via keyword queries, but this technology is limited. These searches cannot identify the type of information on a page. For example, they cannot determine that a string of text is a person's name or that it is the price of a product. Therefore, unlike information in a structured database, information on a Web page cannot be automatically related to information on another page, such as to extract different pieces of data about the same person and combine that information into a single personal profile. The vision of the semantic Web is to establish such capabilities.

KEYWORDS

Semantic Web, Semantic Web Technologies, Web 3.0.

INTRODUCTION

The Semantic Web is the next generation of the current Web in which computers can interpret the meaning of web content because of explicit semantics provided in markup. The Semantic Web components are deployed in the layers of Web technologies and specifications. The traditional version of web i.e. Web 1.0 started as a Read only medium; the next version Web 2.0 established itself as Read/Write medium. Now the currently evolving version of web, viz., Web 3.0 is said to be a technologically advanced medium which allows the users to Read/Write/Execute and also allows the machines to carry out some of the thinking so far expected only from the human beings. In a short time, Web 2.0 and now Web 3.0 have created new tools and technologies for facilitating web based education & learning. To begin with, this paper discusses some definitions of the Web 3.0, its evolution and characteristics. Next, we have discussed about the possible future Web 3.0 technologies, trends, tools and services that will assist in the areas of online learning, personalization and knowledge construction powered by the Semantic Web.

"Web3.0 as a series of combined applications. The core software technology of Web3.0 is artificial intelligence, which can intelligently learn and understand semantics. Therefore, the application of Web3.0 technology enables the Internet to be more personalized, accurate and intelligent."

Figure The Semantic Web Layers

Figure : Evolution of semantic web

SEMANTIC WEB TECHNOLOGY

The idea of using semantic technology on the Web is almost as old as the Web itself, but the concept has only in the last several years begun gaining traction. This has occurred in large part because of the creation of several key standards discussed below.As a result, the semantic Web has progressed significantly in recent years, opening the doors for developers to solve problems that could not be otherwise addressed and to create applications that are not possible with conventional Web technology. But for non-developers, there isn't an easy way, such as a turnkey commercial product, to get started on semantic work.

All content looks the same to conventional Web search technology. A search engine does not distinguish between names, products, prices, and so on. Semantic technology, on the other hand, is a searching infrastructure that resembles database queries, in which different types of information (e.g., addresses, names) are entered in different, corresponding fields. Compared to conventional Web sites, on semantic Web sites information is more than undifferentiated text. The name of a product could be tagged to indicate that it is a certain type of product, and a number displayed next to the product name could be identified by a search utility as a price. Computers could then use this semantically meaningful content to automatically manipulate, combine, compare, and sort information.

The concept of a semantic Web has been around for well over a decade. In recent years, however, the idea has begun to attract more interest and is now being implemented on a small scale. These developments have been enabled by the establishment of the following key standards:

Resource Description Framework (RDF).

RDF is a World Wide Web Consortium (W3C) standard for how to label and describe online content so that computers can treat it as knowledge. A central part of RDF is defining various Web resources so that any system can determine what that resource is. For instance, a resource may be a particular product or it may be a price that applies to a product. In order to apply these definitions, RDF uses uniform resource identifiers (URIs). The term URI is new to many people, but the concept is widely known because of the term uniform resource locator (URL), which is synonymous with a Web page's address. A URL is one type of URI. It is intended specifically for finding files on the Web. The Internet Society defines a URI as a compact sequence of characters that identifies an abstract or physical resource. This specification defines the generic URI syntax and a process for resolving URI references that might be in relative form, along with guidelines and security considerations for the use of URIs on the Internet.

SPARQL. 

Whereas databases are commonly searched using the query language SQL, there is now a query language for the semantic Web: SPARQL. It is a W3C standard that enables queries to be made across RDF data sources. It also defines the XML format in which query results will be returned.

Web Ontology Language (OWL).

 Like RDF, OWL is a system for categorizing and defining information, but it is more granular and flexible. Less mature than RDF, it is envisioned for use in sub-communities of the semantic Web, for cases in which RDF alone does not provide enough flexibility.

Simple Knowledge Organization System (SKOS).

SKOS is a group of specifications, created using RDF, that describe semantic Web "knowledge organization systems," which include any type of classification system or vocabulary on the semantic Web.

DEFINITIONS OF WEB 3.0

The term ‘Web 3.0’ was first coined by John Markoff of the New York Times in 2006, and first appeared significantly in early 2006 in a Blog article "Critical of Web 2.0 and associated technologies such as Ajax" written by Jeffrey Zeldman. Major IT experts and researchers support different approaches to the future Web. There is complete agreement among the experts about how Web 3.0 will evolve. Below we discuss the opinions of pioneers in the field in this respect.Tim Berners-Lee, coined the term Semantic Web, and promotes the concept of conversion of Web into a big collection of databases.

About Web 3.0, Tim Berner Lee says:

"People keep asking what Web 3.0 is. I think maybe when you've got an overlay of scalable vector graphics - everything rippling and folding and looking misty-on Web 2.0 and access to a semantic Web integrated across a huge space of data, you'll have access to an unbelievable data resource."

Netflix founder, Reed Hastings thinks that Web 3.0 would be a full video Web as stated below:

"Web 1.0 was dial-up, 50K average bandwidth; Web 2.0 is an average 1 megabit of bandwidth and Web 3.0 will be 10 megabits of bandwidth all the time, which will be the full video Web, and that will feel like Web 3.0"

CHARACTERSTICS OF WEB 3.0

Four characteristics of Web 3.0, as given below, can be summarized from the above definitions and descriptions.

Intelligence: Experts believe that one of the most promising features of Web 3.0 will be Web with intelligence, i.e., an intelligent web. Applications will work intelligently with the use of Human-Computer interaction and intelligence. Different Artificial Intelligence (AI) based tools & techniques (such as, rough sets, fuzzy sets, neural networks, machine learning etc) will be incorporated with the applications to work intelligently. This means, an application based on Web 3.0 can directly do intelligent analysis, and then optimal output would be possible, even without much intervention of the user. Documents in different languages can be intelligently translated into other languages in Web3.0 era. Web 3.0 should enable us to work through natural language. Therefore, users can use their native language for communication with the others around the world.

Personalization: Another characteristic of Web 3.0 era is Personalisation. Personal or individual preferences would be considered during different activities such as information processing, search, formation of personalized portal on the web. Semantic Web would be the core technology for Personalisation in Web 3.0.

Interoperability: Interoperability implies reuse, which is again a form of collaboration. Web 3.0 will provide a communicative medium for knowledge and information exchange. When a person or a software program produces information on the Web and this information is used by another, then the creation of new form of information or knowledge takes place. Web 3.0 applications would be easy to customize & they can independently work on different kinds of devices. An application based on Web 3.0 would be able to run on many types of Computers, Microwave devices, Hand-held devices, Mobiles, TVs, Automobiles and many others. Pervasive Web is the term used to describe this phenomenon where web is operable to a wide range of electronic devices.

Virtualization: Web 3.0 would be a web with high speed internet bandwidths and High end 3D Graphics, which can better be utilised for virtualisation. The trend for future web refers to the creation of virtual 3-Dimensional environments. An example of the most popular 3-D web application of Web 3.0 is Second Life [7].

TECHNOLOGY TRENDS FOR WEB 3.0

Based upon the above definitions, it is likely that the new generation of web applications will have some specific core technologies to support them. In this section, we present some of the major trends in terms of technologies that might become the building blocks of the next generation of the Web.

Figure 1: Evolution of the Web

Semantic Web: The extension of the World Wide Web that provides an efficient & easier way to share, find and combine data & information from distinct sources is called Semantic Web. In the simplest terms, we can define Semantic Web as a relationship between things, described in a manner which makes people and machines able to understand. We may say,

Traditional World Wide Web = Web of Documents with Limited Interoperability,

Semantic Web = Web of Integrated, Linked meaningful Data.

Semantic Web is all about data integration. The Semantic Web converts "display only" data to meaningful information by using metadata. Ontologies, which contain the vocabulary, semantic relationships, and simple rules of inference and logic for a specific domain, are accessed by software agents. These agents locate and combine data from many sources to deliver relevant information to the user. One of the objectives of Semantic Web is to identify and provide the exact required data that matches the keywords provided by the user. For example, if we search keyword data mining through Google, yahoo or any of search engines, millions of web pages appear as search results out of which a few may have some relevant information and all other pages may be useless. Web 3.0 in terms of Semantic Web is the third generation of World Wide Web in which machines will have the ability to read Web contents like Human beings and also the ability to follow our directions. For example, if you order to check the schedules of all the show timings of a film in theaters, for your preferred timings, within a 20 km radius, then it follows and provides the appropriate information in respect of your preferences.

Future Web (Web 3.0)

Ubiquitous, pervasive content and services

HTTP 1.1, SOAP, RDF, OWL, SWRL, SPARQL, Open APIs

Intelligent Agents,

Semantic Web, Smart Intefaces, Intelligent Search,3D web

The 3D Web: This trend of the future World Wide Web refers to the formation of virtual 3-dimensional worlds on the Web. The use of 3D graphics will be extensively utilized in the development of Web 3.0 tools or applications. High speed Internet, quicker processing speeds, higher screen resolutions, 3D gaming technology and augmented reality will transform the Web browsing into a 3D experience, where you actually move through the virtual corridors of the Web, as a virtual avatar of your real self .Recently several Internet-based elementary virtual worlds, such as Second Life, IMVU, Active Worlds, and Red Light Centre, have gained huge attention by the public worldwide. Users of these virtual worlds are growing in a big way everyday. For instance, at the end of March 2008, Second Life had more than 13 million accounts with around 38,000 users logged on at any particular moment.

The Social Web: The Social Web explains the interaction of people with one another using the underlying technologies of World Wide Web. Technology advancements in Web 3.0 will take the current social computing to a new level called Semantic Social Computing or Socio-Semantic Web which will develop and utilize knowledge in all forms, e.g., content, models, services, & software behavior. Semantic Web and, in general, Artificial Intelligence technologies will add underlying knowledge representations to information, tags, processes, services, software functionalities and behaviors.

The Media Centric Web: The most of traditional search engines provide search results on the basis of text inputs. Web 3.0 searches will not restrict them only to the text based searches. Web 3.0 searches will be able to find out the related similar media objects based on its features. The search engines would be able to take input(s) as a media or a multi-media object and will be able to search out related media objects based on its features. For example, to search images about cars, we need to provide an input as an image of a car and the search engine should be able to retrieve images of cars with similar features. The same kind of search possibilities should be applied with other media objects such as audio and video. The work in this direction is already going on. Some good examples of this kind of technology can be found on software like Ojos Riya photo sharing tool that allows to automatically tag images using face recognition, similarly the site Like.com enables the user to search for products based on similar images.

The Pervasive and Ubiquitous Web: According to Peter Robinson, Ubiquitous and pervasive computing may be defined as the task of embedding small and mobile devices into existing IT and computing infrastructures, so that it allows users to access and manipulate information where and when it matters, even while on the move. The scope and use of web services will not limit us only to computers and mobiles but web services will be equally available in clothing, appliances, and in automobiles and much more. We need not evoke these services every time; they will work and perform their task themselves cooperatively and automatically. The involvement of user to devices to access and work would be almost nothing. For example, using the future web services we can find windows and curtains that check the weather and automatically open and close accordingly; home appliances that know our daily routines and preferences and communicate to each other to provide us with a more comfortable living. As stated above, Web services would play an important role in this direction and device embeddable form of light weight web services will be required. The communication between different types of devices and the Web would be possible with the help of Service Oriented Architectures (SOA) and related technologies for ensuring cross-platform interoperability. Some leading software companies are working in this direction. Microsoft has released a development API also, it has released exceptional innovations featured product called Life Ware, which is an excellent example of what this technology can bring in the future.

APPLICATION OF SEMANTIC WEB

Several years ago, the semantic Web was primarily in a research phase. The few implementations of it were mainly to demonstrate the potential of the idea. While much of the activity related to semantic technology still takes place within the academic community, there are now real-world examples of the technology to use as a model. An early example is the Norwegian National Broadcasters' efforts to use the semantic Web to store extensive metadata about its collection of recordings, with the goal of making the archives highly searchable.

One of the more familiar of today's semantic Web initiatives is the Friend of a Friend Project (FOAF). FOAF is designed to make information on people's personal homepages machine readable, and thus to enable such data to be automatically interrelated. FOAF, which uses RDF, provides a set of terms that can be used to describe people in a standard way. For instance, it defines classes with a syntax such as "foaf: Person." While FOAF is typically talked about and used as a way to describe people, it has the potential to describe other entities, such as companies. Today's semantic Web projects have minimal "curb appeal," limited functionality, and are not user-friendly enough to expand much beyond the crowd of highly technically literate people now using them. The semantic Web concept of tagging is being used extensively by sites such as delicious, and the idea of extracting and re-combining data in new ways is being put to use by application mash-ups. The semantic Web could eventually go beyond the Web 2.0 by creating a broader, standardized system of interrelated information, but such a development is down the road.

CONCLUSION AND FUTURE WORK

Search engines became a critical component of the Web's infrastructure as the Web's size grew. As the Semantic Web grows, we will need search engines that can efficiently handle Semantic Web content. While we can't be sure what form this content will take in the future, the current standard is based on Semantic Web documents.

We have discussed the general differences encountered in building a search engine for Semantic Web documents rather than HTML documents. We've also described in some detail the design and implementation of Swoogle, the First search engine designed for the Semantic Web in the context of the Web. We are continuing to use Swoogle to study the growth and characteristics of the Semantic Web and the current practices in using RDF and OWL. We are also developing new features and capabilities and exploring how it can be used in novel applications. Many open issues remain. One set of open problems involves scale. Techniques which work today with 5 * 106 documents may fail when the Semantic Web has 5 * 108 documents.

Some of these problems could potentially be solved by moving away from COTS open source software we are using to creating custom designed index stores and distributed systems analogous to what Google has done for conventional Web searches. RDF molecules in a reasonably efficient manner. We also need to experiment with how much and where a Semantic Web search engine should reason over the contents of documents and queries. Information encoded in RDF is beginning to show up embedded in other documents, such as PDF and XHTML documents, JPG images and EXCEL spread sheets. When techniques for such embedding become standard, we expect the growth of Semantic Web content on the Web to accelerate dramatically. This

will add a new requirement for hybrid information retrieval systems that can index documents based on words as well as RDF content.

Finally, we are continuing to experiment with how Swoogle can be used to support applications, including Spire, Semdis and Inference Web, Each of which exercises different aspects of a Semantic Web search engine.

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