CS Option C: Web Science Lecture Notes

Introduction

• Exhaustive information dump with a focus on memorization.
• Main difficulty: PHP, HTML, MySQL.
• Overlaps with Topic 3 (Networks).
• HL content is random and weird.
• A study guide will be released shortly.

The Internet vs. The World Wide Web

• Internet: Global network infrastructure (hardware).
• World Wide Web: Collection of web pages stored on internet infrastructure.
• Internet involves ISPs, routers, switches, etc.
• Uses protocols like TCP/IP, DNS, Email, FTP.
• WWW uses HTTP.

Websites and Web Pages

• Website: Collection of related web pages.
• Web Page: Individual page within a website.
• Accessed via web browsers using URLs.

HTTP and TCP/IP

• HTTP: Protocol for transferring web pages.
• TCP/IP: Fundamental protocol for internet communication.

HTTP Requests and Responses

• Request made from client to server; response includes HTML/CSS/JavaScript.
• Process includes DNS resolution, establishing TCP connection, and HTTP request/response cycle.

Secure HTTP (HTTPS)

• Encrypted version of HTTP using SSL/TLS.
• Uses digital certificates to verify website security.

Ports

• Numeric identifiers for network services (e.g., HTTP - 80, HTTPS - 443).

Web Browsers

• Software to access/display content on the WWW.
• Examples: Google Chrome, Safari, Mozilla Firefox.

Cookies

• Small text files stored in web browsers to remember user preferences and login info.

Web Application Development

HTML

• Markup language for creating web pages.
• Structure: head, body, footer, etc.

PHP and MySQL

• Server-side scripting language for dynamic content generation.
• MySQL used for database manipulation.
• Integration: PHP processes HTTP request, interacts with MySQL, returns HTML/CSS/JavaScript.

CSS

• Styles and formats HTML documents.
• Can be stored in separate files and shared among web pages.

JavaScript

• High-level programming language for client-side scripting.
• Adds interactivity to web pages.

Static vs. Dynamic Web Pages

• Static: Unchanging content (e.g., brochure websites).
• Dynamic: Interactive, frequently changing content (e.g., social media sites).

XML and XHTML

• XML: Encodes data in structured format.
• XHTML: Combines XML and HTML features.

Search Engines

• Software to search for information on the WWW using algorithms.
• Process: Crawling, Indexing, Ranking, Results.

Search Engine Algorithms

• PageRank: Evaluates quality of web pages based on in-links.
• HITS: Evaluates based on authority and hub scores.

Search Engine Optimization (SEO)

• Techniques to improve website ranking (e.g., keyword optimization, mobile optimization).
• White Hat: Ethical SEO practices.
• Black Hat: Unethical SEO practices.

Web Paradigms

• Web 1.0: Static web pages.
• Web 2.0: User-generated content, social media.
• Web 3.0: AI, machine learning, blockchain.

Computing Paradigms

• Grid Computing: Distributed computing across multiple networks.
• Mobile Computing: Portable devices (e.g., smartphones).
• Ubiquitous Computing: Integration of computing in everyday environments.
• P2P Computing: Decentralized network of computers.
• Cloud Computing: Remote servers for data storage and processing.

Interoperability and Standards

• Interoperability: Ability of systems to work together.
• Standards: Guidelines for interoperability (e.g., TCP/IP, HTML).
• Open Standards: Publicly available standards.

Creative Commons License

• Allows creators to share work while retaining some rights.

HL Topics

Graph Theory

• Use of directed graphs to represent the web.
• BOW-TIE Model: Structure of the web (core, in-components, out-components, tendrils, tubes).

Ambient and Collective Intelligence

• Ambient Intelligence: Technology integration in environments.
• Collective Intelligence: Collaborative problem-solving by groups.

Power Law Distribution

• Statistical distribution relevant to web connections (few nodes with many links).

This concludes the lecture notes for CS Option C: Web Science.