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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 functionali-ties. In this paper, we present Radoop, an extension for the RapidMiner data(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)
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)
To classify time series by nearest neighbors, we need to specify or learn one or several distance measures. We consider variations of the Maha-lanobis 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)
In this paper, we present two novel class-based weighting methods for the Euclidean nearest neighbor algorithm and compare them with global weighting methods considering empirical results on a widely accepted time series classification benchmark dataset. Our methods provide higher accuracy than every global weighting in nearly half of the cases and they(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 open-source distributed warehouse systems. It is comfortable, and easy to use for preprocessing purposes, but to prove usabil-ity of this application, we created measurement a framework to ensure precise results. These results show that our application(More)
In the past decade, accelerometer sensors became small enough to embed in mobile devices that people are using every day. Thus, arm movements became attractive to control mobile games and game consoles. However, there is no widely-used gesture-vocabulary for controlling devices and gesture recognition is not standardized. Furthermore, there is no(More)