Erika Griechisch | University of Szeged (original) (raw)

Uploads

Papers by Erika Griechisch

Research paper thumbnail of The effect of training data selection and sampling time intervals on signature verification

Based on an earlier proposed procedure and data, we extended our signature database and examined ... more Based on an earlier proposed procedure and data, we extended our signature database and examined the differences between signature samples recorded at different times and the relevance of training data selection. We found that the false accept and false reject rates strongly depend on the selection of the training data, but samples taken during different time intervals hardly affect the error rates.

Research paper thumbnail of Online Signature Verification based on Kolmogorov-Smirnov Distribution Distance

Research paper thumbnail of Some Theoretical Issues Concerning Hamming Coding

Research paper thumbnail of Joint Glossary of Forensic Document Examination and Pattern Recognition

In this paper we introduce an open, scientific glossary which uses MediaWiki engine to the forens... more In this paper we introduce an open, scientific glossary which uses MediaWiki engine to the forensic examiner and pattern recognition scientific communities. Besides our aim to find editors from these communities who contribute to extend the glossary and make it as complete as possible, we would like to translate the terms from English to other languages, e.g. Portuguese, German, Chinese, Japanese, Arabian. The contribution can be started with translating the existing words at the glossary. The second part of our work when the glossary become be more completed, will consist into create the very understanding and useful glossary.

Research paper thumbnail of Offline Signature Verification Using Similarity Measure for Skeletons

Research paper thumbnail of Community Detection by using the Extended Modularity

This article is about community detection algorithms in graphs. First a new method will be introd... more This article is about community detection algorithms in graphs. First a new method will be introduced, which is based on an extension [16] of the commonly used modularity and gives overlapping communities. We list and compare the results given by our new method and some other algorithms yileding either overlapping or non-overlapping communities. While the main use of the proposed algorithm is benchmarking, we also consider the possibility of hot starts, and some further extensions that considers the degree distribution of the graphs.

Research paper thumbnail of Online Signature Verification using Accelerometer and Gyroscope

We investigate the use of different pen hardware for online signature verification. Instead of us... more We investigate the use of different pen hardware for online signature verification. Instead of using the ink information, we analyze the local acceleration and angles of the pen during the signing process. Therefore we introduced novel electronic pens for motion capturing, i. e., we augmented ordinary pens with accelerometers and gyroscopes for measuring the acceleration or local angles, respectively. In this paper we examine captured databases and analyze the expedience of the proposed devices. Furthermore, we present some ideas for future research.

Research paper thumbnail of Online Signature Analysis Based on Accelerometric and Gyroscopic Pens and Legendre Series

2013 12th International Conference on Document Analysis and Recognition, 2013

ABSTRACT In this paper we compare two captured databases which contain local acceleration and ang... more ABSTRACT In this paper we compare two captured databases which contain local acceleration and angle information recorded during the signing process. Approximately a year passed between the capturing of the two databases and they contain several signatures from the same writers. We analyze the expedience of the proposed devices and examine the overlap of the databases using Legendre approximation for feature computation and Support Vector Machine for classification. In addition we plan to make the concerned databases publicly available for research purposes.

Research paper thumbnail of Online signature verification method based on the acceleration signals of handwriting samples

Here we present a method for online signature verification treated as a two-class pattern recogni... more Here we present a method for online signature verification treated as a two-class pattern recognition problem. The method is based on the acceleration signals obtained from signing sessions using a special pen device. We applied a DTW (dynamic time warping) metric to measure any dissimilarity between the acceleration signals and represented our results in terms of a distance metric.

Research paper thumbnail of A systematic approach of multi-person games

International Journal of Internet and Enterprise Management, 2009

ABSTRACT This paper gives a systematic analysis of a special group of multi-person games. By assu... more ABSTRACT This paper gives a systematic analysis of a special group of multi-person games. By assuming linear payoff functions, the order of magnitude of four parameters determines the type of the games. In our study we fix three parameters and systematically vary the fourth one. In this way we can obtain the battle of sexes, the benevolent chicken, the chicken and the maximising differences games. Our systematic approach is based on agent based simulation. It presents the varying characteristics of the different games as well as it shows how the transitions are made from one game to another.

Research paper thumbnail of A simulation study of public goods contributions

International Journal of Internet and Enterprise Management, 2009

ABSTRACT An agent-based simulation study is reported to analyse an inter-group conflict in which ... more ABSTRACT An agent-based simulation study is reported to analyse an inter-group conflict in which agents contribute to provide a public good to all of them, and at the same time the different groups compete for an external prize. This mechanism encourages the group members to contribute instead of free riding. A dynamic version of this multi-player game is analysed in which each player is able to increase their contributed amount depending on the condition that the additional contribution improves her payoff or not. We will examine the dependence of the total contribution on the external prize and the timing of the additional contributions.

Research paper thumbnail of The effect of training data selection and sampling time intervals on signature verification

Based on an earlier proposed procedure and data, we extended our signature database and examined ... more Based on an earlier proposed procedure and data, we extended our signature database and examined the differences between signature samples recorded at different times and the relevance of training data selection. We found that the false accept and false reject rates strongly depend on the selection of the training data, but samples taken during different time intervals hardly affect the error rates.

Research paper thumbnail of The effect of training data selection and sampling time intervals on signature verification

Based on an earlier proposed procedure and data, we extended our signature database and examined ... more Based on an earlier proposed procedure and data, we extended our signature database and examined the differences between signature samples recorded at different times and the relevance of training data selection. We found that the false accept and false reject rates strongly depend on the selection of the training data, but samples taken during different time intervals hardly affect the error rates.

Research paper thumbnail of Online Signature Verification based on Kolmogorov-Smirnov Distribution Distance

Research paper thumbnail of Some Theoretical Issues Concerning Hamming Coding

Research paper thumbnail of Joint Glossary of Forensic Document Examination and Pattern Recognition

In this paper we introduce an open, scientific glossary which uses MediaWiki engine to the forens... more In this paper we introduce an open, scientific glossary which uses MediaWiki engine to the forensic examiner and pattern recognition scientific communities. Besides our aim to find editors from these communities who contribute to extend the glossary and make it as complete as possible, we would like to translate the terms from English to other languages, e.g. Portuguese, German, Chinese, Japanese, Arabian. The contribution can be started with translating the existing words at the glossary. The second part of our work when the glossary become be more completed, will consist into create the very understanding and useful glossary.

Research paper thumbnail of Offline Signature Verification Using Similarity Measure for Skeletons

Research paper thumbnail of Community Detection by using the Extended Modularity

This article is about community detection algorithms in graphs. First a new method will be introd... more This article is about community detection algorithms in graphs. First a new method will be introduced, which is based on an extension [16] of the commonly used modularity and gives overlapping communities. We list and compare the results given by our new method and some other algorithms yileding either overlapping or non-overlapping communities. While the main use of the proposed algorithm is benchmarking, we also consider the possibility of hot starts, and some further extensions that considers the degree distribution of the graphs.

Research paper thumbnail of Online Signature Verification using Accelerometer and Gyroscope

We investigate the use of different pen hardware for online signature verification. Instead of us... more We investigate the use of different pen hardware for online signature verification. Instead of using the ink information, we analyze the local acceleration and angles of the pen during the signing process. Therefore we introduced novel electronic pens for motion capturing, i. e., we augmented ordinary pens with accelerometers and gyroscopes for measuring the acceleration or local angles, respectively. In this paper we examine captured databases and analyze the expedience of the proposed devices. Furthermore, we present some ideas for future research.

Research paper thumbnail of Online Signature Analysis Based on Accelerometric and Gyroscopic Pens and Legendre Series

2013 12th International Conference on Document Analysis and Recognition, 2013

ABSTRACT In this paper we compare two captured databases which contain local acceleration and ang... more ABSTRACT In this paper we compare two captured databases which contain local acceleration and angle information recorded during the signing process. Approximately a year passed between the capturing of the two databases and they contain several signatures from the same writers. We analyze the expedience of the proposed devices and examine the overlap of the databases using Legendre approximation for feature computation and Support Vector Machine for classification. In addition we plan to make the concerned databases publicly available for research purposes.

Research paper thumbnail of Online signature verification method based on the acceleration signals of handwriting samples

Here we present a method for online signature verification treated as a two-class pattern recogni... more Here we present a method for online signature verification treated as a two-class pattern recognition problem. The method is based on the acceleration signals obtained from signing sessions using a special pen device. We applied a DTW (dynamic time warping) metric to measure any dissimilarity between the acceleration signals and represented our results in terms of a distance metric.

Research paper thumbnail of A systematic approach of multi-person games

International Journal of Internet and Enterprise Management, 2009

ABSTRACT This paper gives a systematic analysis of a special group of multi-person games. By assu... more ABSTRACT This paper gives a systematic analysis of a special group of multi-person games. By assuming linear payoff functions, the order of magnitude of four parameters determines the type of the games. In our study we fix three parameters and systematically vary the fourth one. In this way we can obtain the battle of sexes, the benevolent chicken, the chicken and the maximising differences games. Our systematic approach is based on agent based simulation. It presents the varying characteristics of the different games as well as it shows how the transitions are made from one game to another.

Research paper thumbnail of A simulation study of public goods contributions

International Journal of Internet and Enterprise Management, 2009

ABSTRACT An agent-based simulation study is reported to analyse an inter-group conflict in which ... more ABSTRACT An agent-based simulation study is reported to analyse an inter-group conflict in which agents contribute to provide a public good to all of them, and at the same time the different groups compete for an external prize. This mechanism encourages the group members to contribute instead of free riding. A dynamic version of this multi-player game is analysed in which each player is able to increase their contributed amount depending on the condition that the additional contribution improves her payoff or not. We will examine the dependence of the total contribution on the external prize and the timing of the additional contributions.

Research paper thumbnail of The effect of training data selection and sampling time intervals on signature verification

Based on an earlier proposed procedure and data, we extended our signature database and examined ... more Based on an earlier proposed procedure and data, we extended our signature database and examined the differences between signature samples recorded at different times and the relevance of training data selection. We found that the false accept and false reject rates strongly depend on the selection of the training data, but samples taken during different time intervals hardly affect the error rates.