OpenGenus Tech Review Team

Machine Learning (ML)

Sentiment Analysis using LSTM with Keras

Sentimental analysis is one of the most important applications of Machine learning. It is used extensively in Netflix and YouTube to suggest videos, Google Search and others. In this article, we will build a sentiment analyser from scratch using KERAS framework with Python using concepts of LSTM.

Machine Learning (ML)

Long Short Term Memory (LSTM)

Long short-term memory (LSTM) units are units of a recurrent neural network (RNN). An RNN composed of LSTM units is often called an LSTM network. A common LSTM unit is composed of a cell, an input gate, an output gate and a forget gate. It has applications in Speech recognition, Video synthesis

Algorithms

Number of arithmetic progression subsequences in a given set of numbers

The problem is that given an array of n positive integers. The task is to count the number of Arithmetic Progression subsequence in the array. This can be solved using dynamic programming in linear time complexity.

Algorithms

Find the Longest Arithmetic Progression using Dynamic Programming

The problem we will solve is that given a set of integers in sorted order, find length of longest arithmetic progression in that set. This can be solved by brute force in O(N^3) while a dynamic programming approach with take O(N^2) time complexity.

Machine Learning (ML)

Hierarchical Clustering

Hierarchical clustering is a method of clustering. In this method, we find a hierarchy of clusters which looks like the hierarchy of folders in your operating system. This hierarchy of clusters will resemble a tree structure and it is called dendrogram

Machine Learning (ML)

Kernel Principal Component Analysis (KPCA)

Kernel Principal Component Analysis (KPCA) is a non-linear dimensionality reduction technique. It is an extension of Principal Component Analysis (PCA) - which is a linear dimensionality reduction technique - using kernel methods.

cyber security

BlueSmack Attack

Bluesmack is a cyber attack done on bluetooth enabled devices. The attack uses L2CAP (Logic Link Control And Adaptation Protocol) layer to transfer an oversized packet to the Bluetooth enabled devices, resulting in the Denial of Service (DoS) attack.

cyber security

OS Command Injection Attack

OS Command Injection is a form of shell injection attack, mostly used for execution of unauthorized OS commands in the operating system (OS) to target the system (usually a web server) and degrade its performance. In this attack, the hacker aims to find and exploit some of the vulnerable application

cyber security

Malvertising Attack

Malvertising is a type of cyber attack in which an hacker use the online advertising to spread the malware. The attack can infect a system pre-click or post-click. A pre-click malvertisement can be embedded in the main scripts of the page. It can even initiate drive-by-download on visiting the site

cyber security

Fork Bomb Attack

Fork Bomb Attack is a type of denial of service attack which causes the degradation of a system by making it run out of the memory. The attack forks the processes recursively to fill the entire available memory, thus choking system resources. Locating and terminating a Fork Bomb is a tedious process

Data Structures

Fenwick Tree (Binary Indexed Tree)

Fenwick Tree / Binary indexed tree (BIT) is a data structure used to process interval/range based queries. Compared to segment tree data structure, Fenwick tree uses less space and is simpler to implement. One disadvantage is that it can be only used with an operation that is invertible.

Data Structures

Segment Tree

A segment tree is a divide and conquer based data structure used to store information about intervals of some linear data structure. It is a height-balanced binary tree where every node corresponds to an interval of the array. It allows processing interval or range queries in logarithmic time

cyber security

Drive By Login Attack

Drive-By Login is a form of phishing attack in which a hacker sets up the malicious code on the victim's favorite website through through various methods of social engineering and bugs in website. Use anti-phishing tools and keep browser upto date to stay safe from this attack

Software Engineering

Check memory usage in Linux

Five tools to check memory usage on Linux are free, /proc/meminfo, vmstat, top and dmidecode. The difference between clock speed and memory access is increasing day by day. To keep our machines healthy, we want to check the memory usage of several processes and in Linux, we have five tools to do so.

cyber security

Tabnabbing Attack

Tabnabbing is a form of cyber attack which enables an hacker to take the advantage of the idle tabs in the browser and use them for carrying out the phishing attacks. The attack can be carried out even if the javascript is disabled, using the HTML attribute or a "meta refresh" meta element

cyber security

UDP Flood Attack

UDP Flood Attack is a type of Denial of Service attack in which a hacker floods the random ports on the victim host with UDP packets. In this attack, the hacker spoofs the IP Address of the packets, to make sure that the returning ICMP packets don’t reach back to the hacker.

Machine Learning (ML)

Convolutional Neural Networks (CNN)

Convolutional Neural Network (CNN) is an neural network which extracts or identifies a feature in a particular image and is the basis of GoogleNet and VGG19 and used for object detection and classification. CNN has five basic components Convolution, ReLU, Pooling, Flattening and Full connection.

Machine Learning (ML)

Understand basic TensorFlow programming concepts

We understand basic TensorFlow programming concepts using a code to add two numbers in TensorFlow. We created placeholders like tf.placeholder, operations like tf.constant and tf.add, sessions using tf.session and configuration using tf.configProto

Machine Learning (ML)

Training vs Inference

Training and Inference are two major processes of Machine Learning and is deeply connected. Training is the process by which we generate various parameters such as weights and biases which are used in a particular model. Inference is the process of using the trained model to do a particular task

cyber security

DNS Amplification Attack

DNS (Domain Name System) Amplification is a form of reflection based DDoS attack, in which a hacker spoofs the look-up requests to spoof the DNS servers to hide the source of an exploit and also to direct the response to the target. The attack exploits the disparity in the bandwidth consumption

cyber security

IP Spoofing Attack

IP (Internet Protocol) Spoofing is a form of cyber attack in which hacker crafts the IP packets which are used to carry out the DDoS attacks as well as MitM attack. In this attack, the fake crafted IP packets are used to impersonate another system or is used to hide the identity of the hacker.

cyber security

MAC Flooding Attack

MAC (Media Access Control) Flooding is a type of cyber attack done in a network to compromise the security of the network switches. In this attack the network is flooded with the fake MAC addresses. The hacker uses this attack to steal sensitive data that is being transferred in the network.

cyber security

Ping Of Death Attack

Ping of Death (PoD) Attack is a form of DDoS attack, which is used for disrupting the victim network by sending the packets larger then the max size allowed using some arbitrary commands. The attack degrades the targeted system or even freeze the system.

Machine Learning (ML)

Hidden Markov Model

Hidden Markov Model is a stochastic model describing a sequence of possible events in which the probability of each event depends on the state attained in the previous event. Markov model can be used in real life forecasting problems. Simple Markov model cannot be used for customer level predictions

Machine Learning (ML)

Markov Chain

Markov chain is a stochastic model describing a sequence of possible events in which the probability of each event depends only on the state attained in the previous event. It refers to the sequence of random variables such a process moves through, with the Markov property of serial dependence