Robert Neumayer

How to choose a digital preservation strategy: evaluating a preservation planning procedure

An increasing number of institutions throughout the world face legal obligations or business needs to collect and preserve digital objects over several decades. A range of tools exists today to support the variety of preservation strategies such as migration or emulation. Yet, different preservation requirements across institutions and settings make the decision on which solution to implement very diffcult. This paper presents the PLANETS Preservation Planning approach. It provides an approved way to make informed and accountable decisions on which solution to implement in order to optimally preserve digital objects for a given purpose. It is based on Utility Analysis to evaluate the performance of various solutions against well-defined requirements and goals. The viability of this approach is shown in a range of case studies for different settings. We present its application to two scenarios of web archives, two collections of electronic publications, and a collection of multimedia art. This work focuses on the different requirements and goals in the various preservation settings.

Spam Filtering Based on Latent Semantic Indexing

In this paper, a study on the classification performance of a vector space model (VSM) and of latent semantic indexing (LSI) applied to the task of spam filtering is summarized. Based on a feature set used in the extremely widespread, de-facto standard spam filtering system SpamAssassin, a vector space model and latent semantic indexing are applied for classifying e-mail messages as spam or not spam. The test data sets used are partly from the official TREC 2005 data set and partly

The Metro Visualisation of Component Planes for Self-Organising Maps

The self-organising map is a popular unsupervised neural network model which has successfully been used for clustering various kinds of data. To help in understanding the influence of single variables or components on clusterings, we introduce a novel method for the visualisation of component planes for SOMs. The approach presented is based on the discretisation of the components and makes use of the well-known metro map metaphor. It depicts consistent values and their ordering across the map for discretisations of various components and their correlations in terms of directions on the map. In our approach component lines are drawn for each component of the data, allowing the combination of numerous component planes into one plot. We also propose a method to further aggregate these component lines, by grouping highly correlated variables, i.e. similar lines on the map. To show the applicability of our approach we provide experimental results for two popular machine learning data sets.

Bringing Mobile Map-Based Access to Digital Audio to the End User

Private as well as commercial music collections keep growing in size and diversity. With an increasing number of tracks and the resulting complexity users quickly face proplems in handling their collections in an adequate way. At the same time, new business models of online vendors arise and the inherent industry interest in new ways of distribution channels and devices becomes immanent. In this paper, we show alternative ways of interacting with large music collections, based on the Self-Organising Map clustering algorithm applied to an audio feature representation of audio files. We therein focus on the presentation of full desktop applications as well as applications for mobile devices like PDAs and Smartphones with the goal of bringing Music Information Retrieval technologies closer to end users. Further, the presented interfaces give an outlook to means of access to other types of media in streaming environments, e.g. video.

Evaluating preservation strategies for electronic theses and dissertations

Digital preservation has turned into a pressing challenge for institutions having the obligation to preserve digital objects over years. A range of tools exist today to support the variety of preservation strategies such as migration or emulation. Heterogeneous content, complex preservation requirements and goals, and untested tools make the selection of a preservation strategy very difficult. The Austrian National Library will have to preserve electronic theses and dissertations provided as PDF files and are thus investigating potential preservation solutions. The DELOS Digital Preservation Testbed is used to evaluate various alternatives with respect to specific requirements. It provides an approach to make informed and accountable decisions on which solution to implement in order to preserve digital objects for a given purpose. We analyse the performance of various preservation strategies with respect to the specified requirements for the preservation of master theses and present the results.