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

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)

Load Signal and Parameters

We load the signal we need.

load('tecla_piano.mat');

We calculate the sampling period and the number of samples.

Ts = 1/fs;
N = length(data);
n = 0:N-1;
nTs = n * Ts;

Set the number of frequency points which generate the spectrums. We also generate the frequency vector.

nFFT = 2 * fs;
f = (0:nFFT-1) * fs/(nFFT-1);

Time Domain Signal Representation

We represent the input signal in the time domain.

figure;
plot(nTs,data);
title('Input signal, TIME domain');
xlabel('nT_{S} (s)');
ylabel('data[nT_{S}] (V)');
grid on;

Signal Spectrum Analysis

We calculate and observe the spectrum of the signal. From the magnitude spectrum, we decide that we want to filter the signal up to 1000 Hz and we want to remove it completely from 1500 Hz up.... Continue reading "FIR Low-Pass Filter Design with Window Method" »

Torque Problem: Turning Fast with Little Torque

Power transfer mechanisms transform speed to torque. Synchronous devices keep input and output shafts in synchronization.

Power Transfer Mechanisms

• Belts (flat, round, timing)
• Chains (roller, ladder, timing)
• Plastic/Cable Chain (bead, ladder, pinned)
• Friction Driver
• Gears (spur, helical, bevel)

Belt Drives

• Flat Belts: Old design, low power devices, rotating power.
• O-Ring Belt: Moderate efficiency, cheap, requires proper tension alignment.
• V-Belt: Relies on friction, quiet, efficient, allows misalignment.
• Timing Belt: Flexible tooth, synchronous drive, used in wet conditions.

Chain Drives

• Plastic Cable Chain: Three forms (ladder, moving beads onto cable, spiral). Starts with steel cable, over molds rubber teeth.

Tmux Commands Reference

Introduction to Tmux

Tmux (Terminal Multiplexer) is a powerful terminal multiplexer for Unix-like operating systems. It allows you to manage multiple terminal sessions from a single window, enhancing your command-line productivity.

Basic Tmux Commands

$ tmux

$ tmux new -s myname

$ tmux ls

$ tmux a

$ tmux a -t myname

$ tmux kill-ses -t myname

$ tmux kill-ses -a

$ tmux kill-ses -a -t myname

$ tmux source-file ~/.tmux.conf

$ tmux show-options -g

$

Core Electrical Terminology and Definitions

This comprehensive glossary provides clear definitions for key terms used in electrical work, covering components, measurements, safety regulations, and professional qualifications.

A-C: Current, Components, and Connections

• AC (Alternating Current) (Abbreviation): Electrical current that periodically reverses direction.
• Adaptor (Noun): A device for connecting several electric plugs to one socket.
• Amp (Noun): The measure of electrical current (short for Ampere).
• Appliance (Noun): A device or piece of equipment designed for a specific task.
• Cable (Noun): Thick insulated wire used for the fixed wiring of electrical systems.
• Circuit (Noun): The complete path followed by electricity, usually along a wire.
• Conductor

Poodle Instantiation Example

B. The Poodle variable myDog is instantiated as a Poodle. The instance variable size is initialized to "toy". An implicit call to the no-argument Dog constructor is made, initializing the instance variable name to "NoName".

Book Instantiation Example

C. Object myBook is created using the one-argument Book constructor, which uses super to set myBook's title attribute to "Adventure Story". Object yourBook is created using super to call the Publication no-argument constructor to set yourBook's title attribute to "Generic".

Tree Instantiation Example

B. Object tree1 is created using the DeciduousTree constructor, which uses super to set tree1's treeVariety attribute to "Oak". Object tree2 is created using the EvergreenTree... Continue reading "Object Instantiation and Code Examples" »

Search Query Context

The original search query may have intended to find information related to inserting a text box, potentially in the context of creating a crib (cheat sheet). The suggested search term was: crib insert text box.

Relevant Search Results

1. Add or Delete a Text Box in PowerPoint (Office.com)

   office.microsoft.com/en.../add-or-delete-a-text-box-HA010230259.aspx

   Instructions and videos detailing how to add and delete text boxes in Word, Outlook, PowerPoint, and Excel 2007.

2. Add, Copy, or Delete a Text Box in Word (Office.com)

   office.microsoft.com/.../add-copy-or-delete-a-text-box-HA010354856.as...

   Instructions and videos to add, copy, or delete text boxes in Excel, Outlook, PowerPoint, or Word 2010.

3. Text Compressor - Free Source Code and

Aircraft Identification Features

Learn to distinguish different aircraft models by their key visual characteristics:

• A330 vs B777: The B777 doesn’t have winglets, has three wheels per main landing gear strut, and the end of the fuselage is distinct.
• A320 vs B737: Standard Airbus/Boeing differences; B737s have a distinct engine shape (flattened bottom).
• B737 Series: Differences between -200, -300, -400, -500, -600, -700, -800, -900ER are primarily by size.
• B747: All have 4 engines. -200 and -300 do not have winglets, but the -300 has a larger upper deck hump. The -400 has winglets. The SP variant has no winglets and is shorter than others.
• B757: The -300 is significantly larger than the -200.
• B767: The -200 has no winglets. The -400 and -300 have

Common Characteristics of Machines

• Involve a kind of motion.
• Involve a kind of force.
• Make a job easier to do.
• Need some kind of input to make them work.
• Produce some kind of output.

Basic Types of Motion

• Rotary: Going round and round.
• Oscillating: Swinging backwards and forwards.
• Linear: In a straight line.
• Reciprocating: Backwards and forwards in a straight line.

A machine is a device that helps make work easier to perform.

Mechanical Advantage Defined

Mechanical Advantage: When a machine takes a small input force and increases the magnitude of the output force, a mechanical advantage has been produced.

Conservation of Energy Principle

Conservation of Energy: No machine can produce more work than the amount of work that is put into the machine.

The Six Simple

Experiment 01: Network Traffic Analysis in ICS/SCADA

Tools

• Wireshark

Objectives

• Use Wireshark to capture and analyze network traffic to detect anomalies such as unauthorized commands or network scanning.

Deliverable

• A detailed report of traffic patterns and recommendations for mitigations.

Wireshark

Wireshark is a network protocol analyzer used to capture and inspect data packets in real time.

Installing Wireshark on Linux

1. Step 01: Update package lists: sudo apt update
2. Step 02: Install Wireshark: sudo apt install wireshark -y
3. Step 03: Allow non-root packet capture. When prompted, select to allow non-root users to capture packets. If not prompted, run:
   • sudo dpkg-reconfigure wireshark-common
   • sudo usermod -aG wireshark $USER
4. Step 04: Restart your session (log