Auflistung nach Autor:in "Merkl, Dieter"
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- KonferenzbeitragMortalitätsschätzungen in ungleichaltrigen Fichtenwäldern mit Hilfe Neuronaler Netze(Umweltinformatik ’99 - Umweltinformatik zwischen Theorie und Industrieanwendung, 1999) Hasenauer, Hubert; Merkl, DieterWithin forest growth modeling it is understood that individual tree mortality can be captured realistically by relating the average rate of mortality to a few reliable and measurable size or site characteristics using a LOGIT model. In this paper we describe the application of neuronal networks adhering to the unsupervised learning paradigm to predict individual tree mortality. Using the large and representative Norway spruce data sample from the Austrian National Forest Inventory, we train different types of neural network architectures, namely Multi-Layer Perceptron, Cascade Correlation, and Learning Vector Quantization. For training, we use the following learning rules: Error Backpropagation, Resilient Propagation, and Scaled Conjugate Gradient. With an independent data set we evaluate the neural network types to predict individual tree mortality.
- KonferenzbeitragOn the impact of document representation on classifier performance in e-mail categorization(Information systems technology and its applications, ISTA' 2005, 2005) Berger, Helmut; Köhle, Monika; Merkl, DieterThis paper provides an analysis of multi-class e-mail categorization performance. In order to investigate this issue, the quality of various classification algorithms based on two distinct document representation formalisms is compared. In particular, both a standard word-based document representation as well as a character n-gram document representation is used. The latter is regarded as highly noise-tolerant and was originally proposed for automatic language identification and as a convenient means for producing compact document indices. Furthermore the impact of using available e-mail specific meta-information on classification performance is explored and the findings are presented.
- KonferenzbeitragQuerying tourism information systems in natural language(2003) Berger, Helmut; Dittenbach, Michael; Merkl, DieterWith the increasing amount of information available on the Internet one of the most challenging tasks is to provide search interfaces that are easy to use without having to learn a specific syntax and provides a means for finding what they really want. In this paper we present a query interface for an information system in the tourism domain exploiting the intuitiveness of natural language. Furthermore, we will describe the results and our insights from analyzing the natural language queries collected during a field trial in which the interface was publicly accessible. This analysis shows how users formulate queries when their imagination is not limited by conventional search interfaces with structured forms consisting of check boxes, radio buttons and special-purpose text fields.