RecommendationAssistant is on the Nextcloud App Store now

Earlier this year, I announced my Master’s Thesis in Recommendation Systems and Nextcloud, an open source file sync and share software. Since then, things have changed a little bit. RecommendationAssistant was designed to work with two recommendation techniques: Collaborative Filtering and Content-Based Recommendation. Unfortunately, the second technique worked not as good as expected. Office files, … read more …

Software Engineering, Hacks and Solutions

Do you know the situation where you want to test a little change of a pre-tested code “on the fly” and recognize that it does not work any more? I had this situation several times. Therefore, I decided to create a “flood style” blog post where I want to summarize those moments. This “flood type” … read more …

Kotlin Cheat Sheet

For a project I was involved in at short notice, I had to become familiar with the Kotlin programming language. Before starting to code, I wanted to get familiar with the syntax and the language itself. As writing on a paper is the best way to learn (for me), I created the following Cheat sheet. Enjoy! … read more …

Role Based Access Control and Big O

Didapptic.com is a research based web application that measures Android and iOS Apps from a didactic point of view. Actually, we work on a new release in order to provide a fresh layout and smarter handling of app data. Among other things, the new release introduces also a new user management handling which allows and/or permits … read more …

Comparing Objects with PHP

Yesterday, I was working on PHPAlgorithms (again). When trying to implement Graphs (Directed and Undirected), I found out that a node could not be found in the graph although I was sure it was there. After a lot of debugging and reverse engineering, I found out that: the adjacency list, which contains all adjacent nodes … read more …

PHPAlgorithms is there

Frankfurt, May 2018 – Today, the first BETA version of PHPAlgorithms is launched! The repository is available via GitHub and Packagist. Originally launched as a research project, PHPAlgorithms provides currently a basic set of data structures. The repository has been designed to provide simple usage of common data structures such as lists, maps and trees. … read more …

PHP HashMap Implementation

A few days ago I have started working on a PHP library for algorithms and data structures. PHPAlgorithms is still in progress and thus has a early beta status. But today, I have pushed the first data structure which is nearly full implemented: HashMaps. A HashMap is characterized among others by its key-value storage property. … read more …

TF-IDF keyword extraction

For my masters thesis I have researched Content-Based Recommendation and keyword extraction as a part of it in detail. One interesting point regarding to keyword extraction is the “quality” of keywords, meaning that if a keyword is descriptive for a document or not. TF-IDF Definition For TF-IDF keyword extraction it is necessary to have a … read more …

Item-Based Collaborative Filtering

Für ein Projekt an der Uni beschäftige ich mich seit längerer Zeit mit Empfehlungssystemen (Recommender Systems), welche i.d.R. aus Collaborative Filtering und Content-Based Recommendation Techniken bestehen. In diesem Blogpost möchte ich auf die Collaborative Filtering-Komponente, genauer auf das Item-Based Collaborative Filtering eingehen. Das Item-Based Collaborative Filtering wurde ursprünglich von Amazon entwickelt. “Traditionelles” Collaborative Filtering, besser … read more …