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Tensors and Variables in PyTorch and TensorFlow

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Tensors and Variables in PyTorch and TensorFlow

Here's a brief explanation of tensors and variables in the context of deep learning frameworks like PyTorch and TensorFlow:

Tensors

  • Definition: A tensor is a multi-dimensional array used to represent data (such as scalars, vectors, matrices, or higher-dimensional data).
  • Common Operations: Tensors can be manipulated with mathematical operations (addition, multiplication, etc.), reshaped, sliced, etc.

In PyTorch, tensors are the core data structure:

import torch
# Create a tensor
a = torch.tensor([[1, 2], [3, 4]])
# Basic operations
b = a + 2         # Adds 2 to each element
c = a * a         # Element-wise multiplication
d = a @ a         # Matrix multiplication

Output:

Tensor `b`: [[3, 4], [5, 6]]
Tensor
... Continue reading "Tensors and Variables in PyTorch and TensorFlow" »

Core Python for Data Analysis and Scientific Computing

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Key Concepts in Data Science & Scientific Computing

Visualization Techniques

  • Overlapping Histograms: Use semi-transparent alpha parameter for comparison.

Data Structures & Algorithms

  • BFS Implementation: collections.deque is ideal for Breadth-First Search.
  • Grid Representation: Obstacles often represented by a value like 1.

Jupyter Notebook & Markdown

  • Markdown Headings: Use # prefix for headings in Jupyter Markdown cells.

Optimization & Least Squares

  • Normal Equations: Direct matrix inversion for Least Squares: β = (XᵀX)⁻¹Xᵀy.

Numerical Integration & Simulation

  • Orbit Simulation: Runge–Kutta 4th order method is a common integration technique.

Search Algorithms

  • Brute-Force Search: Often implemented using nested loops.

Python Ecosystem

... Continue reading "Core Python for Data Analysis and Scientific Computing" »

Cybersecurity Threat Landscape: Actors, Vectors, and Defenses

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🔎 Threat Actors & Their Attack Paths

Who is attacking?

Threat Actors are the people or groups launching attacks. Mnemonic: “NO HIS” (Nation-State, Organized Crime, Hacktivists, Insiders, Script Kiddies).

Actor TypeMotivationTactics
Nation-State (APT Groups)Espionage, warfareAdvanced, persistent attacks
Organized CrimeFinancial gainRansomware, phishing
HacktivistsSocial justice, ideologyWebsite defacement, data leaks
InsidersRevenge, profitData theft, sabotage
Script KiddiesFun, fameLow-skill attacks using existing tools

How do threats reach systems?

Threat Vectors are the attack paths used by threat actors. Mnemonic: “MFWDVN” (Messages, Files, Websites, Devices, Vendors, Networks).

Attack PathExampleHow It Works
Message-BasedPhishing, smishingTrick
... Continue reading "Cybersecurity Threat Landscape: Actors, Vectors, and Defenses" »

C++ Concepts: Exception Handling to Friend Functions

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Exception Handling

#include <iostream>
#include <stdexcept>
using namespace std;
int main() {
    try {
        int numerator = 10;
        int denominator = 0;
        int res;
        if (denominator == 0) {
            throw runtime_error("Division by zero not allowed!");
        }
        res = numerator / denominator;
        cout << "Result after division: " << res << endl;
    }
    catch (const exception& e) {
        cout << "Exception " << e.what() << endl;
    }
    return 0;
}

Operator Overloading

#include <iostream>
using namespace std;
class Test {
private:
    int num;
public:
    Test(): num(8){}
    void operator ++() {
        num = num + 2;
    }
    void Print() {
... Continue reading "C++ Concepts: Exception Handling to Friend Functions" »

CUDA Matrix Multiplication: Shared Memory

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CUDA Matrix Multiplication Using Shared Memory

This code demonstrates matrix multiplication in CUDA, leveraging shared memory for optimization. It includes two examples: a kernel using shared memory and a host-side implementation using the Thrust library.

CUDA Kernel with Shared Memory

The following CUDA kernel performs matrix multiplication using shared memory to optimize data access:


__global__ void matMulShared(int *A, int *B, int *C, int rowsA, int colsA, int colsB) {
    __shared__ int tile_A[TILE_SIZE][TILE_SIZE], tile_B[TILE_SIZE][TILE_SIZE];
    int row = blockIdx.y * TILE_SIZE + threadIdx.y, col = blockIdx.x * TILE_SIZE + threadIdx.x, temp = 0;
    for (int i = 0; i < (colsA + TILE_SIZE - 1) / TILE_SIZE; ++i) {
        if (row <
... Continue reading "CUDA Matrix Multiplication: Shared Memory" »

Nmap, Netcat, and Metasploit Commands Cheat Sheet

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Nmap Options

-PE: Quickly check if host is up.

-sn: Disable port scanning (host discovery).

-n: Disables DNS resolution (checks IP online without looking up hostnames).

-O: OS detection.

-A: OS detection, Version detection, Script scanning, traceroute.

-sV: Service detection (banner info, version).

-vV: Provides verbose output.

-sC: Scan with default scripts for additional info gathering.

--min-rate=5000: Ensures scan sends at least 5k packets per second.

nmap --script smb-enum-shares.nse -p 445 (ip): List shares and their properties.


To see scripts starting with X: ls /path/X

To execute script with script tracing: sudo nmap -script=smb-os-discovery -script-trace target_ip

To enumerate the SMB share files: sudo nmap -script=smb-enum-shares target_ip

Vulnerability... Continue reading "Nmap, Netcat, and Metasploit Commands Cheat Sheet" »

Assembly Instruction Set Categories and Functions

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🧾 Data Transfer Instructions

These instructions are used to move data between registers, memory, and I/O ports.

InstructionUse
MOVTransfer data between registers or memory locations
PUSH / POPPerform stack operations (store/retrieve data)
XCHGExchange contents of two operands
IN / OUTInput from or output to a port
LEALoad Effective Address
LDS / LESLoad Pointer and Segment Register
XLATTranslate byte using a lookup table

➕ Arithmetic Instructions

These instructions perform basic mathematical operations.

InstructionUse
ADD / SUBAddition / Subtraction
ADC / SBBAdd/Subtract with Carry/Borrow
INC / DECIncrement / Decrement a value
MUL / IMULUnsigned / Signed Multiplication
DIV / IDIVUnsigned / Signed Division
NEGTwo's Complement (Negation)
CMPCompare operands
... Continue reading "Assembly Instruction Set Categories and Functions" »

C Implementation of Queues, Linked Lists, and Search Algorithms

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Circular Queue Implementation Using Linked Lists

This C program demonstrates the implementation of a circular queue using a linked list structure. The queue handles integer data.

Data Structure Definition

#include <stdio.h>
#include <stdlib.h>

typedef struct QueueType {
    int Data;
    struct QueueType *Next;
} QUEUE;

QUEUE *Front = NULL; // Pointer to the front of the queue
QUEUE *Rear = NULL;  // Pointer to the rear of the queue

// Function prototypes
void Enqueue(int Num);
int Dequeue();
void DisplayQueue();
int Menu();

Enqueue Operation

The Enqueue function inserts a number into the circular queue. It handles memory allocation and maintains the circular link by ensuring Rear->Next always points to Front.

void Enqueue(int Num)
... Continue reading "C Implementation of Queues, Linked Lists, and Search Algorithms" »

Java Code Examples: User Name Generation and Repair Scheduling

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This document presents Java code snippets demonstrating two distinct functionalities: user name generation and management, and a car repair scheduling system. Each section includes method implementations with explanations of their purpose and logic.

User Name Management System

The UserName class is designed to generate and manage potential user names based on a user's first and last names. It also provides functionality to filter out names that are already in use.

UserName Class Constructor

This constructor initializes a UserName object, populating a list of possible user names. It assumes that firstName and lastName are valid strings containing only letters and have a length greater than zero.

import java.util.ArrayList;

public class UserName {

... Continue reading "Java Code Examples: User Name Generation and Repair Scheduling" »

Blue Prism RPA Roles, Governance, and ROM Foundations Q&A

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RPA Governance and Demand Pipeline Management

Demand Pipeline Prioritization Steps

Which of the following does not describe the “Prioritization” step as part of managing the demand pipeline?

R: Helping a friend

Head of Robotic Automation Role and Responsibility

Which of the following statements are true when describing the role and responsibility of the Head of Robotic Automation?

R: All of the above

RPA Governance Board Objectives

Select from the below which statement best describes the Demand Generation objective within the RPA Governance Board?

R: Identify quality RPA automation opportunities

Select from the below which statement best describes the Demand Management objective within the RPA Governance Board?

R: Responsible for defining and prioritizing

... Continue reading "Blue Prism RPA Roles, Governance, and ROM Foundations Q&A" »