Chandigarh, Thursday, June 10, 1999
|XML is the new driving force
As the World Wide Web gets into full swing with E-commerce, where transactions are made online, simple HTML tags are fast becoming obsolete and are giving way to a new language XML which is said to be the driving force behind the E-commerce, says T.M.S. Virdi.
XML is the new driving force
SEVERAL years ago when the World Wide Web burst into scenes, critics predicted a swift death for the "Internet thing". Because they thought that the Internet was never designed to support a large commercial network. At that time it was hard to believe that telephone lines would carry millions of packets of data, and would be used for online transactions. They even thought that languages and bandwidth will not allow Internet to grow any further. At that time Hyper Text Markup Language, or HTML was not designed for the purpose of building Web pages. HTML was accepted as the language of the World Wide Web mainly because it happened to be there and because it was easy to learn. So with these "borrowed", accidental components, how could the Web ever turn into a successful commercial network?
Against the odds, the World Wide Web has proven to be a master at adaptation and innovation and the people who design Web pages are jugglers who have learned endless ways of putting old tools to new use.
HTML itself is a prime example. There are more than 400 million Web pages that make up the World Wide Web today. They are all based on the same sets of tags, more or less, but used in different and novel combinations that make some Web pages look like works of art and others rather plain. Proof that HTML, although easy to learn and read, is not easy to put to good use.
Building sophisticated Web pages with HTML is a very difficult job particularly if you are looking to create a professional Web page. There are softwares to help and tips and tricks for inspiration, but for a simple Markup Language/HTML is not extensible, meaning that you cannot add your own tag(s). You can only use the tags that are commonly interpreted by most of commonly available browsers. Over the years, Microsoft and Netscape (the two leading browser providing companies) have added countless tags and new methodologies in an effort to upgrade the usability of the language. With HTML 4.0 emerging as yet another standard, it appears that HTML has simply exhausted itself. The only way up is to extend (See illustration for an HTML coding).
To overcome this problem of extensibility another standard has emerged; SGML (Standard Generalised Markup Language) which is fully extensible. SGML is a Meta Language:a language that builds MarkUp Languages. HTML is one that is already there but SGML can formulate others too. You could ideally create your own markup languages such as Chemical Markup Language (CML) or a Medical Markup Language (MML). And there is virtually no limit. For clarity, the tags for each language could have names consistent with the terminology used in each field. For example, you could formulate a <disease></disease> tage in medical context. Customised tags like that would make it easier to publish specialised information such as a Medical Database, because the Database can associate fields with tags in the Web page.
Extensible Markup Language
With the emergence of SGML life remains difficult for some, as SGML is a complicated language and difficult to understand. It was developed to describe a document and its formatting in such a way that the documents appearance would be independent of software applications. In SGML, Document Type Definitions (DTDs) have to be formulated for each Markup Language, and this is a complex process. To bridge the gap between the sophisticated SGML and the simple HTML, the World Wide Web Consortium, W3C, has specified a compromise in the form of XML (Extensible Markup Language) and XML looks set to feature in all serious Web sites of the future. In simple words: XML is an extremely simple dialect of SGML.
XML, like its mother language, is a MetaLanguage that retains all the key SGML advantages such as extensibility in a format that is much easier to learn, use and implement than a full SGML. However, it is not as easy to understand as HTML. It offers some important advantages over the latter: support for complex document structures and the ability to validate the structure of a document automatically. In addition, XML has better linking qualities. XML is so versatile that it is an ideal choice for embedding databases with your web pages. Further, XML offers a special feature by virtue of which a web page can be viewed with a different perspective.
While surfing the web, I came across an interesting site (www.webreview.com) that has a good definition of XMLs power: "A plain text file is one dimensional. It contains no information about its contents. An HTML file is two dimensional; it contains basic markup that describes the elements of a document. HTML enables a set of applications to process the document. With XML, documents become multidimensional capable of being processed by different programmes, delivered by different methods, and displayed in different views. In XML, each document is an object and each element of the document is an object."
Dynamic HTML (DHTML) is another language that was introduced to make our life simple. However, it has an embedded feature of Object Oriented techniques. Using Document Object Model (DOM) you could bring Static and boring Web pages to life. Previously, contents would be cut and pasted into a static pre-defined HTML template, to be published to the Web. If the Web server was connected to a Database, the contents of the page could be changed as and when needed, but no further changes were possible unless they were made manually, page by page. With the introduction of Cascading Style Sheets (CSS), changes could be made to the appearance of all Web pages carrying the <style> tags from within the page or from one central location, such as a Style Sheet definitions page residing on the Web server and accessible to all HTML pages. Style Sheets, as the name implies, can change colour and font attributes of a Web page.
Every element in the page (like Table, Text and Photographs etc.) are treated as objects in DHTML, so using programming languages like Java and Visual Basic Scripts one could create amazing things. It means that the presentation of contents changes as and when the mouse moves over it; for example, a table can highlight sections of text or present a drop-down menu for further navigation. This gives Web designers much more control over the appearance of a Page, but it still does not do much for the user who is presented with information that he cannot change from his side. Until now, Markup Language has been more concerned with presentation than with data. Enter XML.
One of XMLs strengths is the way the Web pages data interact with the DOM. Because XML permits customised tags, it builds data structures which are then presented in a dynamic format, in any way the user chooses to view the data. For example, you could be viewing an online catalogue page with 6 columns of information presented side by side. If you wanted to see only the last column, say with the prices, you would simply click a preference button and the page would hide the first five columns. Structuring data in a MetaLanguage also means that the data can be viewed on media other than Web pages: mobile phones, print media even. XMLs data structures, in true transport fashion, can be used by all sorts of software, not just by Web browsers.
The XML Linking Language XXL enables vastly improved hyperlinking facilities. From the DOM perspective, hyperlinks are also perceived as objects, and as such can do a lot more than simply provide a jump to another page. Links can produce little drop-down menus of related links, or a small message screen they can even changed from outside the Web page.
If one wants to design a Web page in a foreign language then XML offers an easier life. The language is defined in UniCode, meaning that it can represent virtually any character set and can even mix them. For example, you could have an English Web page in UniCode with reference to Greek words, and both languages would be displayed by the browser in their native character sets. CommerceNet is one of the main organisations which has actively incorporated XML. E-commerce standards and terms are being drawn up under the guidance of CommerceNet and this should eventually lead to products getting a universal identity on the Internet; a unique tag that acts like the barcode on product packaging. Such E-commerce tags will specify details of price, size and colour among others and will make product easy to find, list and compare.
Home pages, announcements, static sites, anything that only needs to be read can still be presented in HTML. HTML is, and will always be, the easier option of the two. "Power users", companies with lots of information that needs to be catalogued, categorised or organised in any way, will be looking at XML to save themselves money in the long term and pave the way for some serious E-commerce. Code once, use in many different ways is more cost effective, than re-coding for each application. From that viewpoint alone, XML is worth a thought.
At the moment, XML
documents can only be viewed through an XML parser or XML
processor, even though the MS IE 4.0 and 5.0 browsers
already support some XML applications with CDF, Microsofts
Channel Definition Format. Both Netscape and
Microsoft, however, have plans to include full XML
support in the next versions of Navigator and Internet
Explorer. When they do, the Battle of the Browsers looks
set to shift from the HTML to the XML field. With this we
can draw a conclusion that XML is set for a long run in
Another forever calendar
EVERY one keeps an account of important events of his daily life. He records these in terms of date, month and year. Generally the day of week is neglected. But many a times he needs to know the day on a particular date. For the lack of old calendars he finds himself helpless. Here arises the necessity of a forever calendar.
One such forever calendar was published in the Science Magazine of The Tribune on May 13. The attempt of the authors was really worth praising, but it was somewhat difficult to use because of its complexity. I hereby present another forever calendar which is simpler than that and perhaps the simplest among all forever calendars made till now.
This is based on the fact that every calendar repeats itself after 10000 years. In other words the calendars of 1999, 11999, 21999 etc. are the same. As such, we have to consider the last four digits only. Thus a calendar for 10000 years can be used forever. Here we shall call the number made from last to digits as year and the number made from other two digits as century. (For example in 1947; 47 is year and 19 is century.)
This calendar is divided into five boxes, which respectively contain years, century-codes, months, days of week and dates. The second box has century-codes. These century codes are the remainders after dividing the century by 4. For example, the century-code for 19 is 3. Similarly century-code for 20 is 0 and so on.
The third box contains months. Here some January and February months are written in small rectangles. These are meant for leap years only.
The method of using this calendar will be illustrated by taking an example to find the day on Aug. 15, 1947.
First of all, locate 47 in the first box, showing years. From this point move towards right side having the same row and find century-codes 3. (because century code for 19 is 3). From this 3 go downwards in the same column and find the month (August). Put a finger of left hand on it.
Now from fifth box, which has dates, locate date 15 and put your right hand finger on it. Move left hand finger towards rightside and right hand finger upwards. The both will meet on Friday. So the day on August 15, 1947 was Friday. In the same way the day on any other date can be found.
This calendar starts from 1 A.D. and will continue forever if the present system of leap-years continues.
1. The father was a chemist, meteorologist and physicist and is known for popularising science in pre-independence Punjab. The son was a renowned botanist and geologist and first Indian D. SC. from Cambridge University. The grandson is a geologist working at Panjab University and has recently made significant contribution to the study of fossils. Name the trio.
2. Having achieved excellent successes in satellite launch technology, the Indian Space Research Organisation is now planning a much bigger mission which may become a reality by the year 2008. What is this mission?
3. MIDCAB is a new coronary bypass technique that is safer, less painful, cheaper and requires shorter post-operative recovery period as compared to the traditional bypass surgery. What is the full form of MIDCAB?
4. Of all the 92 elements from hydrogen to uranium included in the basic periodic table, only two are not found in nature. Which are these two elements and what are their atomic numbers?
5. What name is given to the non-biological conditions like water, soil, air, light, temperature etc. which shape the physical environment of a living organism?
6. Edible oil is generally adulterated with argemone oil which is very harmful for human health. To test for the adulterant, a few drops of a concentrated acid are added to the edible oil and the mixture shaken. Appearance of red colour in the acid layer indicates the presence of argemone oil. Which acid is used for this test?
7. Which two gases are mainly found in stars? By which process is energy produced in stars?
8. Name the process used for measuring and recording the changes in the conductivity of nerves of arthritic or other patients.
9. By applying a torque (a couple of forces) of suitable strength in a suitable direction, a player can impart an appropriate spin to a ball and make the ball move in any desired direction. What is this phenomenon called?
10. Can you tell about how many silk worms are killed to make yarn for one silk saree of average length?
1. Ruchi Ram Sahni; Birbal Sahni; Ashok Sahni
2. Destination Moon
3. Minimally Invasive Direct Coronary Bypass
4. Technetium (43) and Promethium (61)
5. Abiotic factors
6. Nitric acid
7. Hydrogen andhelium; Nuclear fusion
9. Magnus effect
Apropos of the article "Proper Utilisation of Flyash" (May 27) sincere efforts are already underway on the part of the PSEB to transform flyash for proper utilisation. It has already commissioned a brick kiln at Lehra Mohabat, which is producing about 25,000 30,000 flyash bricks per day and the PSEB has made commitment to purchase 50 lakh bricks annually for four years for use on its works. As an incentive the firm has been given interest free loan, land on nominal lease and free flyash. This brick kiln is consuming annually about 10000 tonnes of flyash. The PSEB has already used about 115 lakhs of these bricks on its civil construction works in colony, plant area and pond area at Lehra Mohabat. Even now work is going on with these bricks for constructing service building and workshop building. These are being used at GNDTP, Bathinda as well. Instructions have also been issued to various offices of PSEB falling within a periphery of 50 km from Lehra Mohabat to use flyash based bricks in their civil works.
The PSEB has also made all-out efforts with the Punjab Govt. to make the use of these bricks mandatory in all government departments, autonomous bodies etc. It has also got these introduced in Punjab CSR and PWD Specification. The acceptability by the public is awaiting the implementation by the Government.
So far as Portland Pozzolana Cement (PPC) is concerned the PSEB is utilising more than 25,000 tonnes of PPC on its civil works every year.
Fat sounds from skinny speakers
MEASURING just millimeters thick, Benwins funky prototype speakers produce high-quality sound in eyecatching packages. Its current flat panel speaker, the BW 2000, costs $ 129. Other models, including these prototypes designed by RKS, are expected later this year. Flat panel speaker technology form NTX makes these speakers possible (Popular Science).
New fish species in South Pacific
A US ichthyologist has discovered a new fish species in the coastal waters of New Zealand.
The new species discovered by Dominique Didie Dagit of the US Academy of Natural Sciences belongs to the genus chimaera, an ancient deep sea relative of sharks, according to a release from the Academy.
Described by Dagit as Chimaera panthera or leopard chimaera, the species has distinguishing leopard-like brown spots over the body and fins.
These fishes evolved 400 million years ago during the Devonian period and are one of the oldest fish species alive today.
This is the first species of chimaera to be discovered in New Zealand and the sixth species to be recognised in the genus.
Mosaics created by a robot
Scientists at the Fraunhofer Institute for Manufacturing Engineering and Automation in Stuttgart have devised a robotic system capable of carrying out mosaic art work in a better and easier way.
The classical art of mosaic that adorns many an ancient villa and chapel, is a task of arduous manual labour because workers have to select and put one tile at a time.
But the new robotic system makes the job easier by preparing the tiles ready for laying, according to a report in Fraunhofer Gesellschaft Research News.
First, the robot is "instructed" how the completed mosaic is to look. The corresponding image is scanned after determing the size of each tile and their width apart are pre-determined.
Customers can create the mosaic from any picture or photograph they desire. It can be previewed and altered in advance to finalise the colours and sizes of tiles.
Complete data are then transferred to the production system the robot work cell and the work cell computer.
Modern trees are 370 million years old
The earliest known modern tree was an extinct plant that lived about 370 million years ago, Reuters reports quoting studies by a team of international botanists.
The plant, called Archaeopteris, had the same structure of modern trees but it took millions of years for it to evolve into the mighty giants that fill forests today.
For decades, botanists description of the first tree were based on leaves and bit of wood in fossil rocks.
In a report in the journal Nature, Brigitte Meyer-Berthaud of the University of Montpellier in France and colleagues in the US and Germany described how they found 150 fossilised examples of the extinct plant in three locations in Morocco.
"Here we describe the largest group of anatomically preserved Archaeopteris remains ever found and provide the first evidence that, in terms of development and branching strategies, these 370-million-year-old plants were the earliest known trees," they said.
"The attachment of branches was the same as modern trees with swelling at the branch base to form a strengthening collar and with internal layers of wood dovetailed to resist breaking," Stephen Scheckler of the Virginia Polytechnic Institute, who collaborated on the research, said.
Detection of bacteria in seven minutes
Identifying, monitoring and isolating the source of an outbreak of infectious disease can be made easy with a new portable instrument developed by American scientists.
The instrument, which rapidly detects and characterises microbial pathogens, takes about seven minutes to detect the presence of a pathogen.
Developed by scientists at Lawrence Livermore National Laboratory in California, the instrument is based on a DNA-testing method and can be used for a wide variety of environmental and clinical samples.