Black-box transfer-based attacks on images

In the previous post we reviewed a series of white-box adversarial attacks where the adversary has full access and knowledge of the victim model. In this post we are going to explore the first category of black-box attacks, namely, black-box transfer-based attacks. Transfer-based attacks generate adversarial examples against a substitute model, possibly being as much similar as possible to the target model, which have a … Continue reading Black-box transfer-based attacks on images

White-box adversarial attacks on images

In the first post we introduced the concept of adversarial attacks and contextualized in the case of images. In this post we are going to explore the first category of attacks, namely, white-box attacks. Under this setting, the adversary has full access and knowledge of the model, that is, the architecture of the model, it’s parameters, gradients and loss respect to the input as well … Continue reading White-box adversarial attacks on images

Introduction to adversarial attacks on images

Nowadays, image classification deep learning models are always more present in our systems in order to create smarter applications or simply to replace human operators to automatically perform some repetitive tasks. Their increased utilization is due to their high accuracy such that recent models are now able to outperform humans’ brain in many object classification tasks. However, despite their good generalization, deep neural networks are … Continue reading Introduction to adversarial attacks on images

MovieSearch: a smart movie search engine

MovieSearch is a content specific search engine with the aim to retrieve movie information given the contents of a user’s query. The search engine relies on the OkapiBM25 algorithm and takes into consideration the text present in the overview, the title, the names of the cast, and the production companies of each movie. The backend has been developed with the framework Django while the front-end … Continue reading MovieSearch: a smart movie search engine

Analysis of parallel version of PageRank algorithm

In this post we are going to analyze a simplified parallel version of the famous algorithm PageRank, the algorithm used by Google Search to rank web pages in their search engine results. The code of the algorithm has been written in C++ exploiting the library OpenMP to parallelize the code. Finally it has been tested over different number of threads as well as different scheduling policies in order to compare … Continue reading Analysis of parallel version of PageRank algorithm

The hacker, the photographer and the rival: Path Traversal

Artbit is an online social network where users can register for free and upload their own digital pictures in order to share them with the world and get popularity. To attract more visitors, the creators of the social network have launched a challenge on their platform which will reward the user who will upload the best picture. Any user can join the competition by simply … Continue reading The hacker, the photographer and the rival: Path Traversal

Playing Pacman with Multi-Agents Adversarial Search

In this post we are going to design various artificial intelligence agents to play the classic version of Pacman, including ghosts and capsules. Pacman is a famous Atari game developed back in 1979 by a nine-persons team and then released in 1980 by the former Japanese developer and publisher of arcade video games Namco. The great success the game had at the time, made it … Continue reading Playing Pacman with Multi-Agents Adversarial Search

AIs Battle Royale: The ultimate snake

In a previous post, we developed two AIs to play the game of Snake, of which, the first one implements a heuristic algorithm to select its moves while the second one consists of a deep neural network trained with a reinforcement learning algorithm (Deep Q-Learning). Afterward, in a second post, we used a genetic algorithm to create different generations of snakes where the best individuals … Continue reading AIs Battle Royale: The ultimate snake

Printing Neatly

Consider the problem of neatly printing a paragraph with a monospaced font (all characters having the same width) on a printer. The input text is a sequence of n words of lengths l1, l2,…,ln, measured in characters. We want to print this paragraph neatly on a number of lines that hold a maximum of M characters each. Our criterion of “neatness” is as follows. If a given line … Continue reading Printing Neatly

Count of Range Sums

Given an integer array nums, return the number of range sums that lie in [lower, upper] inclusive. Range sum S(i, j) is defined as the sum of the elements in nums between indices i and j (i ≤ j), inclusive. A naïve algorithm of O(n2) is trivial. You MUST do better than that. Difficulty: Very hard. Input The first line contains 3 integers separated by spaces: n, representing the length of the integer array nums. lower. upper. The second line is the integer … Continue reading Count of Range Sums