1

Internet Programming with Logic Programming Languages and

Constraint Solvers• Paul TarauPaul Tarau

• University of North Texas & BinNet University of North Texas & BinNet CorporationCorporation

• http://www.cs.unt.edu/~tarauhttp://www.cs.unt.edu/~tarau

• http://www.binnetcorp.comhttp://www.binnetcorp.com

• tarau@cs.unt.edu, tarau@cs.unt.edu, tarau@binnetcorp.comtarau@binnetcorp.com

2

PART I: An Overview of Internet Development Trends

• A Goal Oriented view:

– WHY to develop for the Internet?

– WHAT to develop for the Internet?

– HOW to develop for the Internet?

• Emphasizing: from the public library to the shopping mall - the new focus on E-Commerce -

3

Internet Growth: driven by E-Commerce

• Critical mass needed: ~20% online

• from random graphs: sudden emergence of a big component

• Growth of E-commerce (US)1998 -> $29 billion1999 -> $98.4 billion2003 -> $1.2 trillion (source: eMarketer)

4

Buying over the Internet

• Initial markets: software, travel, books, CDs - MP3

• online stock trading: Schwab, E-Trade, Suretrade

• online grocery: back to the future:-) HomeGrocer, NetGrocer, Peapod

• online drugstores?

5

Auctioning systems/electronic markets

• eBay, priceline

• price comparison/item matching agents:

– EBay's Personal Shopper

– Amazon’s book recommandations

• more conventional shopping chart?

• refereal programs: Amazon, priceline

6

Trends in E-Commerce

• Integration of e-commerce and corporate data processing systems

– backend databases: DB2, Oracle

• Complete e-commerce solutions vs. component based e-commerce systems

– complete solution offerings: IBM

– CGI scripts (Perl), servelets, SSI, Active Server Processes (ASP)

7

Internet based e-commerce infrastructure

• WWW - still in exponential growth for the next few years

• payment is just Information Exhange - subject to automation!

• Shopping by features: search, online browsing can do it better than asking a (not always) knowledgeable salesperson

• place for LP/CP: the need for intelligent knowledge processing

8

Encryption, digital signatures

• conventional cryptography: DES, BlueFish• public key cryptography: RSA, PGP• confidentiality: PGP only a given group can

decode, no need for key exchange• authentication

– digital signature, certificates - VeriSign etc.• virgin territory for LP/CP: cryptography!

9

Secure transactions

• SSL basic security built in most browsers, alternative: SHTTP– still much better than conventional paper

based security

• DES: is it good for business transactions? (40 bit ok, 128bit - truly secure)

10

Forms of electronic payment

• Electronic Money

– anonymus, unforgeable, “sound” - a place for LL?

• smart cards - downloadable from online account

• is third party certification needed?

• E-checks vs. credit cards vs. e-cash

11

Predictions/Trends?

• E-commerce will completely reshape financial institutions

• it is likely to replace various forms of catalog and mail order businesses

• successful in information based (books, CDs), high margin/low volume, expensive to keep in inventory products

12

Search Engines, Portals, Service Sites

• Trend: from Information to Knowledge - a place for LP/CP

• Search engines: AltaVista, Snap, NorthernLight

• Portals: Yahoo, Lycos

• Specialized service sites:

– books: www.amazon.com

– travel: www.itn.com

13

Basics of Internet Infrastructure: TCP/IP

• packet switching vs. dedicated point-to-point link

• Post Office (small packets ) vs. Phone Center (point-to-point link)

• IP header: address 129.120.44.123 vs.

• domain based naming: www.cs.unt.edu

14

Static vs. Dynamic IP addresses

• self contained server and web site: static IP

• connecting through an ISP: dynamic IP:-(

– in fact, this comes from running out of available IP addresses - upcoming extended IP numbers might solve this - it is quite humiliating for users to be: cust007.my_isp.com instead of being www.JamesBond.com :-)

15

How to create and register a new domain?

• www.internic.net: (not a NSI monopoly anymore!)

• new agency: http://www.icann.org/

• http://www.networksolutions.com/

• Whois service: http://www.nsiregistry.com/

16

How to create a Web Site?

• Dedicated server

– T1 (large volume, high cost) or ISDN (metered, slow, starts to look outdated)

– new: DSL from GTE (in Dallas-FW area)

– What OS? Linux+Apache (more flexible) NT (compatible with other MSoft tools)

• Through Web hosting (inexpensive and reliable but less flexible)

17

Web Site Design Issues

• Usability issues (quick access to frequently visited pages)

• Artistic issues (colors, layout, style)

• Designing for speed (*.mid *.jpg vs. *.wav, animated *.gif)

• Good and bad business web sites - ratings!

• Style: look at major media companies: www.cnn.com, www.disney.com!

18

Hypertext Markup Language (HTML) basics

• <HTML>

• <HEAD>

• <TITLE> Welcome To My Page </TITLE>

• </HEAD> <BODY>

– other html code

• </BODY>

• </HTML>

19

Adding Links

• <A HREF=

• “http://www.mycompany.com”>

• My Company

• </A>

• In the Web page it looks like this:

– … My Company …

• <A HREF="mailto:a@b.c.d">my email</A>

20

Including Images and Sound

• <IMG SRC=pictures/me_and_my_dog.gif>

• good compression: JPG

• animated GIFs - easy to make - size can be a problem

• Sound: MID (small) WAV, AU (older formats) MP3 (high quality)

• static (tag: EMBED, BGSOUND) vs. streaming audio/video: RealAudio

21

Including CGI scripts

• <form method="post”

• action="http://a.b.c.d/cgi-bin/myscript.exe?query=who" >>

• <input type="submit" size="40" value="Search">

• </form>

22

Including Java Applets

• <applet

• code=”myapplet.class"

• height="200" width="600” >

– <param

• value=”999”

• name=”default_price" >

• </applet>

23

Tools for Building Web Sites

• HTML, tables, forms, CGI scripts

• server side tools: SSI, ASP, servlets

• Media formats: GIF, JPEG, MPEG, real audio

• Executable content: Java

24

Design tools

• Composer, Microsoft Word, FrontPage

– Generating HTML

• Generating Java applets: Symantec, J++ 6.0

• Generating 3D content: VR Creator, TrueSpace

• LP/CP tools need to interoperate with them!

25

Alternative Content Formats

• VRML - now supported also by Java3D

– has links like in HTML

– has superior navigation

– has higher information density

• The future is 3D - the Nintendo generation grows up:-)

• LP/CP tools should interoperate with the emerging 3D Web

26

Conclusion

• LP/CP comes late into the Internet Business

• it should get into fast growing or still emerging areas

– e-commerce

– intelligent search, knowledge processing, agents

– 3D Web, new Internet infrastructure