Zoltán Prekopcsák

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Working with large data sets is increasingly common in research and industry. There are some distributed data analytics solutions like Hadoop, that offer high scalability and fault-tolerance, but they usually lack a user interface and only developers can exploit their functionalities. In this paper, we present Radoop, an extension for the RapidMiner data(More)
Gesture is a natural expression form for humans, but its recognition is a similarly hard problem as speech recognition. In this paper, I present a real-time hand gesture recognition system, which identifies relevant parts in the continous sensor data stream, and classifies them to the most probable gesture. Instead of the usual button-based segmentation, I(More)
Proper classification of action potentials from extracellular recordings is essential for making an accurate study of neuronal behavior. Many spike sorting algorithms have been presented in the technical literature. However, no comparative analysis has hitherto been performed. In our study, three widely-used publicly-available spike sorting algorithms(More)
To classify time series by nearest neighbors, we need to specify or learn one or several distance measures. We consider variations of the Mahalanobis distance measures which rely on the inverse covariance matrix of the data. Unfortunately — for time series data — the covariance matrix has often low rank. To alleviate this problem we can either use a(More)
Hand gesture interfaces gained great popularity due to game consoles in the past few years and they have the potential to appear in our everyday lives too. In this paper, we introduce four design principles for an everyday hand gesture interface. We evaluate related works and show a prototype that has been designed and developed with these principles in(More)
We describe an accelerometer based activity recognition system for mobile phones with a special focus on personal time management. We compare several data mining algorithms for the automatic recognition task in the case of single user and multiuser scenario, and improve accuracy with heuristics and advanced data mining methods. The results show that daily(More)
We introduce a user-friendly graphical data preprocessing application based on Hive, one of the well known opensource distributed warehouse systems. It is comfortable, and easy to use for preprocessing purposes, but to prove usability of this application, we created measurement a framework to ensure precise results. These results show that our application(More)