The Technologies

The third common use of the term Semantic Web is to identify a set of technologies, tools and standards which form the basic building blocks of a system that could support the vision of a Web imbued with meaning. The Semantic Web has been developing a layered architecture, which is often represented using a diagram first proposed by Tim Berners-Lee, with many variations since. Figure 1 gives a typical representation of this diagram.

• While necessarily a simplification which has to be used with some caution, it nevertheless gives a reasonable conceptualisation of the various components of the Semantic Web. We describe briefly these layers.
• Unicode and URI: Unicode, the standard for computer character representation, and URIs, the standard for identifying and locating resources (such as pages on the Web), provide a baseline for representing characters used in most of the languages in the world, and for identifying resources.

The Semantic Web has lived its infancy as a clearly delineated body of Web documents. That is, by and large researchers working on aspects of the Semantic Web knew where the appropriate ontologies resided and tracked them using explicit URLs. When the desired Semantic Web document was not at hand, one was more likely to use a telephone to find it than a search engine. This closed world assumption was natural when a handful of researchers were developing DAML 0.5 ontologies, but is untenable if the Semantic Web is to live up to its name. Yet simple support for search over Semantic Web documents, while valuable, represents only a small piece of the benefits that will accrue if search and inference are considered together. We believe that Semantic Web inference can improve traditional text search, and that text search can be used to facilitate or augment Semantic Web inference. Several difficulties, listed below, stand in the way of this vision.

Introduction
The current evolution of the Web can be characterized from various perspectives [Jasper & Uschold 2001]:

Locating Resources: The way people find things on the Web is evolving from simple free text and keyword search to more sophisticated semantic techniques both for search and navigation.

Users: Web resources are evolving from being primarily intended for human consumption to being intended for use both by humans and machines .

Web Tasks and Services: The Web is evolving from being primarily a place to find things to being a place to do things as well [Smith 2001].

All of these new capabilities for the Web depend in a fundamental way on the idea of semantics. This gives rise to a fourth perspective along which the Web evolution may be viewed:

• Semantics—The Web is evolving from containing information resources that have little or no explicit semantics to having a rich semantic infrastructure.

Having a Purchase Order means that you already checked out items you wish to pay (conference registration fee). This does not mean you already paid for it. You have to click on the Paypal button (Click here to pay in Figure 1a) found at the upper left hand corner of the Purchase Order to proceed with online payment at the Paypal website to finalize your registration. Otherwise, your online registration transaction will be treated as temporary and you may lose your slot.

After clicking on the button, you will be prompted to enroll a Paypal account by entering your credit card details to safely pay online. This is much more secure than entering your credit card details directly on to the website other than Paypal. (Note: Make sure you have a credit card such as Visa, MasterCard, Discover, and American Express to be able to create a PayPal account)

The PayPal Sandbox is a self-contained environment within which you can prototype and test PayPal features and APIs. The PayPal Sandbox is an almost identical copy of the live PayPal website. Its purpose is to give developers a shielded environment for testing and integration purposes and to help avoid problems that might occur while testing PayPal integration solutions on the live site. Before moving any PayPal-based application into production, you should test the application in the Sandbox to ensure that it functions as you intend and within the guidelines and standards set forth by the PayPal Developer Network (PDN).

Get Started Quickly: Integration Center
PayPal’s Integration Center at https://www.paypal.com/integration has step-by-step details for getting started with the PayPal Software Development Kits (SDKs), Website Payments Pro, Express Checkout, Website Payments Standard, Authorization & Capture, Instant Payment Notification, and more.

Visit the Integration Center at: https://www.paypal.com/integration

Alternative Query Types
cache:
Display Google’s cached version of a web page.
cache:www.irs.gov (Show Google’s cached version of the US Internal Revenue Service home page.)

info:
Find info about a page.
info:www.theonion.com (or id:)
(Find information about The Onion website.)

related:
List web pages that are similar or related to the URL
related:www.healthfinder.gov
(Find websites related to the Healthfinder website.)

Restrict Search to Sites Where Query Words Appear
allinanchor:
All query words must appear in anchor text of links to the page.
allinanchor:useful parenting sites (Search for pages that are called useful parenting sites by others.)

inanchor:
Terms must appear in anchor text of links to the page.
restaurants Portland inanchor:kid-friendly
(Search for pages on Portland restaurants for which links to the page say they are “kid friendly.”)

allintext:
All query words must appear the in text of the page.
allintext:ingredients cilantro chicken lime
(Search for recipes with these three ingredients.)