1 World Wide Web Concepts (Chapter 18) 인공지능연구실

2 목 차  Elements of the Web  Web Browsers  Keeping Tracking of your Favorite Web sites  Security and Privacy Issues  Blocking Offensive or Inappropriate Web Sites  Purchasing Products Online with Wallet Programs

3 Elements of the Web(1)  Clients and Servers  Web’s Languages and Protocols  Urls, Transfer Protocols  HTML, Java and JavaScript, VBScript, XML, Image Formats 등  Web Pages and Web Sites  Special Kinds of Web Sites and Pages  포탈 (Portals)  Web guides  검색 엔진 (Search Engines)

4 Elements of the Web(2)  Clients and Servers  Hardware  Web server  Web’s file 을 저장, 제공하는 인터넷에 연결된 컴퓨터  Web client/Web browser  웹 서버로부터 웹 문서 요청

5 Elements of the Web(3)  Web’s Languages and Protocols  URLs and Transfer Protocols  URL(Uniform Resource Locator ) : Internet file address  예 )  Http(Hyptertext Transfer Protocol) : Web 통신 규약  HTML(Hypertext Markup Language)  W3C(World Wide Web Consortium) : HTML standard 정의   Java and JavaScript  Java : language for small applications(applets) over the Web  JavaScript : language for extending HTML

6 Elements of the Web(4)  Web’s Languages and Protocols  VBScript and ActiveX Controls  for MS Internet Explorer  Visual Basic Script  ActiveX controls : embed executable programs  XML (Extensible Markup Language)   Image Formats  JPEG, GIF (chapter 26, 29)  Audio and Video Formats  VRML (Virtual Modeling Language) : 2-D, 3-D view

7 Elements of the Web(5)  Web Pages and Web Sites  Web Page  HTML document on a Web server  예 )  Web Site  collection of Web pages  home page : front door  예 )

8 Elements of the Web(6)  Special Kinds of Web Sites and Pages  Portals  start page  예 ) Yahoo, Lycos, Excite 등  Web Guides  top-down approach  분류 : categories and subcategories  Yahoo, Excite 등의 portal sites 에서 처음 제공  Search Engines  bottom-up approach  query

9 Web Browsers  Web browser  웹 페이지를 보여주는 프로그램  HTML viewer  예 ) Netscape Navigator, Mircosoft Internet Explorer  Default browser  Browser Home Page  browser’s home button  Plug-Ins  웹 브라우저와는 별개의 프로그램으로 웹 브라우저와 함께 수행  예 ) RealAudio, RealVideo

10 Keeping Track of Your Favorite Web Sites  Bookmarks  HTML file of links, 브라우저에 포함  Internet shortcuts  Web page 연결 Icons, 바탕화면에 위치  Favorites  folder of Internet shortcuts, 시작메뉴에 위치  History  최근에 access 했던 웹 페이지 리스트

11 Security and Privacy Issues(1)  Cookies  log file  사용자의 웹 서버 접근 정보를 저장  Firewalls  서로 다른 networks 간의 보안을 위한 Hardware or Software  Intranet 에 허용되지 않은 사용자의 접근을 막음  Secure Communications and Transactions  Secure Transaction : Secure sockets layer  public key cryptography  digital certificates (

12 Security and Privacy Issues(2)  Executable Applets and Scripts  application bug  security risk  ActiveX controls : install and run without warnings  disabling ActiveX controls  Viruses  Privacy Implications of Browser Caches and History  cache : temporary storage area  clearing cache and history  Adjusting Your Security Settings

13 Security and Privacy Issues(3)  Anonymous Web Browsing Through Proxies  web browsing anonymously through proxy  proxy’s IP address 로 Web page 를 Access  proxy site 

14 Blocking Offensive Web Sites(1)  PICS  Platform for Internet Selection  labeling system  HTML 문서의 내용에 적절한 label 부여  web browser 는 사용자 설정과 비교하여 display 여부 결정  PICS-compliant : PICS 를 기반으로 한 rating system  관련정보 

15 Blocking Offensive Web Sites(2)  Content-Rating Services : SafeSurf and RSAC  PICS-compliant rating system  SafeSurf by parents’ group Netscape NetWatch  RSAC(Recreational Software Advisory Council) by Software Publishers Association, MS, IBM, Disney 등 Netscape NetWatch, MS Content Advisor

16 Blocking Offensive Web Sites(3)  Recommendation for PICS Web Site Blocking  PICS : internet 이용 범위 제한, unrated web sites 처리 어려움  그러나 청소년의 유해한 사이트 접근 제한할 수 있음.  Non-PICS Web Site Blocking  The Internet Filter Assessment Project(TIFAP)  created and run by librarians 

17 Purchasing Products Online with Wallet Programs(1)  Wallet Program  사용자의 신용카드 번호와 주소를 암호화하여 저장  Microsoft Wallet, CyberCash Wallet 등  Security Issues  using Secure Sockets Layer(SSL)   digital signature  encrypted, password-protected format

18 Purchasing Products Online with Wallet Programs(2)  Microsoft Wallet  Installing Wallet   Entering Information into Microsoft Wallet  Internet Option 선택 후 information 입력  CyberCash Wallet  download and install 