Notes, summaries, assignments, exams, and problems for Technology

Malware

Malicious software, is a type of software that has been particularly designed to gain access to or damage a computer, mostly without the knowledge of the owner. There are a lot of types of malware, including computer worm, computer viruses, Trojan horse, adware and spyware.

Computer Crime

Defined as a crime in which a computer is the object of the crime (hacking, phishing, spamming) or is used as a tool to commit an offense (child pornography, hate crimes). Cybercriminals may use computer technology to access personal information, business secrets or use the internet for malicious purposes.

Trojan Horse

A type of malware that is often disguised as legitimate software. Trojans can be employed by cyber-thieves and hackers that offer useful... Continue reading "Understanding Malware and Cybercrime: A Comprehensive Guide" »

Brakes

Disc Brakes

A disc is connected to an axle. Brake pads apply pressure to the disc via friction.

Band Brakes

A drum is connected to an axle. A flexible band applies pressure to the outside of the drum.

Drum Brakes

A drum is connected to the axle. A pair of brake shoes apply pressure to the inside of the drum via friction.

Energy Absorption and Dissipation

Springs

Springs are devices that, thanks to the elasticity of their materials and their shape, can absorb energy when force is applied. This energy can then be dissipated in a controlled way. Depending on the type of external force applied, springs work in different ways:

• Compression: Pushing on the spring makes it shorter (e.g., a sofa).
• Traction: Pulling on the spring makes it longer (e.g., a

Fundamentals of Computer Networking

What is a Computer Network?

A computer network is a set of interconnected devices (computers, servers, peripherals) designed to share resources and exchange information efficiently.

Network Classification by Size (Scope)

Networks are classified based on their geographical scope:

• LAN (Local Area Network): Covers a small, localized area, such as a home, office, or school campus.
• MAN (Metropolitan Area Network): Spans a city or large campus.
• WAN (Wide Area Network): Extends over a large geographical distance, often connecting multiple LANs (e.g., the Internet).

Network Classification by Property

Networks can be categorized based on access rights and ownership:

• Public Networks: Networks where access is available to the

Material Classification

Natural Materials

These materials are obtained directly from nature, such as:

• Wood
• Coal
• Metal
• Stone

Artificial Materials

These materials are derived from natural materials through processing, such as:

• Glass
• Paper
• Cement

Synthetic Materials

These materials are created through chemical reactions involving artificial materials, such as:

• Plastics

Material Types and Their Properties

Ceramics

Ceramics exhibit the following properties:

• Fragility
• Low thermal conductivity
• Low electrical conductivity
• Hardness
• Brittleness

Metallic Materials

Metals possess these characteristics:

• High electrical and thermal conductivity
• Resistance
• Ductility
• Malleability
• Ability to form alloys with other elements to enhance properties

Plastics/Polyesters

Plastics and polyesters... Continue reading "Understanding Materials: Properties, Types, and Treatments" »

Fundamentals of Structural Engineering

A structure is the set of elements in a body designed to resist the forces (loads) acting upon it, fulfilling three essential conditions:

1. Stability: Remaining upright and preventing overturning.
2. Resistance: Withstanding loads without breaking.
3. Rigidity: Minimizing deformation under load.

Understanding Loads

The forces acting on a structure are known as loads. These loads are typically classified as either permanent (dead loads) or variable (live loads).

Classification of Structures

Structures are generally categorized into four main types:

• Massive Structures: Characterized by their large volume and weight (e.g., pyramids, stone benches).
• Vaulted Structures: Utilize arches and vaults to distribute forces (e.g., stone

Computer Basics

A computer is a device that processes data according to a set of instructions known as a program.

Hardware and Software

Hardware: The equipment. Software: The programs and data.

Operating System

The operating system is a special set of programs that provides an interface for the user and allows application programs to communicate with the hardware.

Application Programs

Application programs include:

• Word processors (for creating and editing texts)
• Spreadsheets (for calculating mathematical formulae)
• Databases (for storing data in a way that allows the data to be sorted and searched)

Antivirus Programs

Antivirus programs are used to detect and remove viruses (harmful programs that can reproduce themselves and attach themselves to other programs)... Continue reading "Computer Hardware, Software, and Peripherals: A Comprehensive Look" »

Steel: Properties and Characteristics

Steel: One pound of steel has more strength than one pound of most other materials. Steel is generally equally strong in tension and compression. There are many ways to use it: columns can be spaced at great distances, and long spans are possible. Steel corrodes if not protected and loses strength when exposed to fire. Steel contains iron.

Types of Steel

• Carbon Steels: 0.15–1.8% carbon (includes spring steels).
• Alloy Steels: Contain additional ingredients such as chromium; stainless steel typically contains about 12% chromium and is more rust resistant.

Tips: Higher carbon content increases hardness and can make steels more difficult to weld.

Shapes and Sections

Shapes:

• W = wide-flange
• C = channel
• S = I-section

• Unit 7