Notes, summaries, assignments, exams, and problems for Other courses

Memory Models in Operating Systems

• Model A (MS-DOS):
  • Structure: Large user space at the top, small RAM at the bottom.
  • Performance: Fast execution, long boot time.
  • Protection: No protection.
• Model B:
  • Structure: Small ROM at the top, small user space at the bottom.
  • Performance: Protected OS but slow (the entire OS must be read).
  • Flexibility: Not flexible.
• Model C (Windows 11):
  • Structure: Select drivers at the top, large user space in the middle, RAM at the bottom.
  • Performance: Fast and secure (key drivers stored in ROM).

Memory Protection and Management

Core Memory Management Issues

• Relocation Problem: Without memory abstraction, loading multiple programs causes incorrect memory addresses.
• Base and Limit Registers:
  • Base: Value added to addresses to find

IoT Protocols

Link Layer Protocols

• 802.3 Ethernet Standards

  A collection of wired Ethernet standards that provide data rates from 10 Mb/s to 40 gigabits per second. The shared medium in Ethernet can be a coaxial cable, twisted-pair wire, or optical fiber. This shared medium carries communication for all devices on the network.

• 802.11 Wi-Fi Standards

  A collection of wireless Local Area Network (WLAN) communication standards.

Network/Internet Layer

• Responsible for sending IP datagrams from the source network to the destination network.
• Handles host addressing and packet routing based on IPv4 or IPv6.
• Datagrams contain a source and destination address, which are used to route them from the source to the destination across multiple networks.
• IPv4 uses 32-

What is a Web Service?

A Web Service allows two applications or systems to communicate with each other over the internet. It’s like one program calling another program to request data or instruct it to perform an action.

Even if these applications are developed with different programming languages or run on different computers, they can still work together using Web Services.

Key Things to Know

• Works Anywhere: Web Services use common standards (like HTTP, XML, JSON), ensuring compatibility across various systems and platforms.
• Communicates Over Internet: Most Web Services transmit and receive data using HTTP or HTTPS — the same protocols websites use.
• Shares Data in Common Formats:
  • XML: Often used in older or more structured systems (e.g., SOAP)

Probability Distributions for Discrete Events

The following table matches common scenarios to their appropriate probability distributions:

Lesson 1: Industry 4.0 and Digital Foundations

Industry 4.0 Concepts

A technological revolution integrating automation, cyber technology, and data exchange. Key components include:

• Robotics
• Big Data
• Artificial Intelligence (AI)
• Internet of Things (IoT)
• 5G

Internet of Things (IoT) Components

Key ingredients enabling the Internet of Things:

1. Communications Infrastructure: Enables devices to connect and share data.
2. Standardization: Ensures compatibility between different systems.
3. Device Availability: Expands the number of connected devices available.
4. Data Revolution: Enables real-time analysis and informed decision-making.
5. Scalable and Accessible Technology: Allows businesses to implement IoT solutions effectively.

Internet Democratizing Forces

The internet democratizes... Continue reading "Industry 4.0, Data-Driven Marketing & MarTech Essentials" »

Crispy Fried Calamari Recipe

Ingredients

• 1 large squid, cleaned
• 170g all-purpose flour
• 200ml sparkling water
• 2 large eggs
• 1 lemon
• 8g baking powder
• Olive oil, for frying
• Salt, to taste
• Fresh parsley, for garnish

Utensils

• Chef's knife
• Spoon
• Deep frying pan or pot
• Skimmer or slotted spoon
• Mixing bowls

Steps

1. Clean the squid: Thoroughly clean the squid, removing their heads and ink sacs. Rinse well under cold water.
2. Heat the oil: Heat olive oil in a deep frying pan or pot to 350-375°F (175-190°C). It is advisable to fry in small batches to maintain oil temperature and ensure crispiness.
3. Prepare the squid: Cut the cleaned squid bodies into rings.
4. Dredge and coat: In a bowl, combine flour, baking powder, and a pinch of salt. In another bowl, beat the eggs with sparkling

Understanding Node.js Modules & Core Functionality

In Node.js, modules are fundamental. They represent reusable blocks of code that can be exported from one file and imported into another, promoting a modular and organized application structure. Node.js features a built-in module system, allowing developers to utilize core modules, create custom modules, or integrate third-party modules.

Core Modules in Node.js

Core modules are pre-packaged with Node.js, offering essential functionalities for common tasks like file system operations, HTTP request handling, and path manipulation.

Some commonly used core modules in Node.js are:

• fs (File System): For interacting with the file system.
• http (HTTP): For creating HTTP servers and clients.
• path (Path)

OFDMA Principles in Wireless Communication

Orthogonal Frequency Division Multiple Access (OFDMA) is a multi-user version of Orthogonal Frequency Division Multiplexing (OFDM). It divides the available spectrum into multiple orthogonal subcarriers, which are then assigned to different users to improve spectral efficiency and minimize interference.

Key Features of OFDMA

• Orthogonality: Subcarriers are spaced at intervals to avoid interference.
• Resource Allocation: Dynamic assignment of subcarriers to users based on channel conditions.
• Multipath Resilience: Effective against frequency-selective fading by using smaller subcarriers.
• Flexible Bandwidth Usage: Different users can occupy varying amounts of spectrum dynamically.

Cyclic Prefix: Mitigating ISI

Statistical Measures and Causal Inference Concepts

Measures of Dispersion and Relationship

Variance

Variance: Estimates how far a set of numbers (random) are spread out from their mean value.

Covariance

Covariance: The relationship between two variables.

• Cov = 0: Unsure of the relationship.
• Cov > 0: Suggests Y will be above average when X is above average.
• Cov < 0: Suggests Y will be below average when X is above average.

The formula for variance is often expressed as: $\mathbb{E}[X^2] - (\mathbb{E}[X])^2$ (where $\mathbb{E}$ is the Expected Value).

The formula for covariance between two variables $X$ and $Y$ is: $\mathbb{E}[(X - \mathbb{E}[X])(Y - \mathbb{E}[Y])]$

Pearson's Correlation Coefficient

Standardizes covariance between -1 and 1:

Pearson’s