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In the mid-1990s, the Faculty of Linguistics and Literary-Studies at Bielefeld University began to establish the field Text technology, both in research and education. Text technology is a new field of research on the border of Computational Linguistics and Computational Philology.
This paper focuses on Text technology in academic education. In 2002, Text Technology was introduced as a minor subject for B.A. Programs. It is organized in modules: Module 1 introduces the characteristics of electronic texts and documents, typography, typesetting systems and hypertext. Module 2 introduces one or two programming languages relevant to the field of humanities computing. Markup languages and the principles of information structuring are the main topics of Module 3. The formal fundamentals of computer-based text processing, as formal languages and their grammars, Logics et cetera are subjects of another module. The paper ends with a short description of other Bachelor- and Master-Programs at Bielefeld University which contain text technological themes.
Die zentrale Aufgabenstellung des Verbundprojektes TextTransfer (Pilot) war eine Machbarkeitsprüfung für die Entwicklung eines Text-Mining-Verfahrens, mit dem Forschungsergebnisse automatisiert auf Hinweise zu Transfer- und Impactpotenzialen untersucht werden können. Das vom Projektkoordinator IDS verantwortete Teilprojekt konzentrierte sich dabei auf die Entwicklung der methodischen Grundlagen, während der Projektpartner TIB vornehmlich für die Bereitstellung eines geeigneten Datensatzes verantwortlich war. Solchen automatisierten Verfahren liegen zumeist textbasierte Daten als physisches Manifest wissenschaftlicher Erkenntnisse zugrunde, die im Falle von TextTransfer (Pilot) als empirische Grundlage herangezogen wurden. Das im Verbund zur Anwendung gebrachte maschinelle Lernverfahren stützte sich ausschließlich auf deutschsprachige Projektendberichte öffentlich geförderter Forschung. Diese Textgattung eignet sich insbesondere hinsichtlich ihrer öffentlichen Verfügbarkeit bei zuständigen Gedächtnisorganisationen und aufgrund ihrer im Vergleich zu anderen Formaten wissenschaftlicher Publikation relativen strukturellen wie sprachlichen Homogenität. TextTransfer (Pilot) ging daher grundsätzlich von der Annahme struktureller bzw. sprachlicher Ähnlichkeit in Berichtstexten aus, bei denen der Nachweis tatsächlich erfolgten Transfers zu erbringen war. Im Folgenden wird in diesen Fällen von Texten bzw. textgebundenen Forschungsergebnissen mit Transfer- und Impactpotenzial gesprochen werden. Es wurde ferner postuliert, dass sich diese Indizien von sprachlichen Eigenschaften in Texten zu Projekten ohne nachzuweisenden bzw. ggf. auch niemals erfolgtem, aber potenziell möglichem Transfer oder Impact unterscheiden lassen. Mit einer Verifizierung dieser Annahmen war es möglich, Transfer- oder Impactwahrscheinlichkeiten in großen Mengen von Berichtsdaten ohne eingehende Lektüre zu prognostizieren.
Die Darstellbarkeit lexikalischen Wissens – am Beispiel kommunikativer Ausdrücke des Deutschen
(1995)
We address the detection of abusive words. The task is to identify such words among a set of negative polar expressions. We propose novel features employing information from both corpora and lexical resources. These features are calibrated on a small manually annotated base lexicon which we use to produce a large lexicon. We show that the word-level information we learn cannot be equally derived from a large dataset of annotated microposts. We demonstrate the effectiveness of our (domain-independent) lexicon in the crossdomain detection of abusive microposts.
We present a gold standard for semantic relation extraction in the food domain for German. The relation types that we address are motivated by scenarios for which IT applications present a commercial potential, such as virtual customer advice in which a virtual agent assists a customer in a supermarket in finding those products that satisfy their needs best. Moreover, we focus on those relation types that can be extracted from natural language text corpora, ideally content from the internet, such as web forums, that are easy to retrieve. A typical relation type that meets these requirements are pairs of food items that are usually consumed together. Such a relation type could be used by a virtual agent to suggest additional products available in a shop that would potentially complement the items a customer has already in their shopping cart. Our gold standard comprises structural data, i.e. relation tables, which encode relation instances. These tables are vital in order to evaluate natural language processing systems that extract those relations.
In this paper, we examine methods to automatically extract domain-specific knowledge from the food domain from unlabeled natural language text. We employ different extraction methods ranging from surface patterns to co-occurrence measures applied on different parts of a document. We show that the effectiveness of a particular method depends very much on the relation type considered and that there is no single method that works equally well for every relation type. We also examine a combination of extraction methods and also consider relationships between different relation types. The extraction methods are applied both on a domain-specific corpus and the domain-independent factual knowledge base Wikipedia. Moreover, we examine an open-domain lexical ontology for suitability.
Automatic Food Categorization from Large Unlabeled Corpora and Its Impact on Relation Extraction
(2014)
We present a weakly-supervised induction method to assign semantic information to food items. We consider two tasks of categorizations being food-type classification and the distinction of whether a food item is composite or not. The categorizations are induced by a graph-based algorithm applied on a large unlabeled domain-specific corpus. We show that the usage of a domain-specific corpus is vital. We do not only outperform a manually designed open-domain ontology but also prove the usefulness of these categorizations in relation extraction, outperforming state-of-the-art features that include syntactic information and Brown clustering.
We examine the task of separating types from brands in the food domain. Framing the problem as a ranking task, we convert simple textual features extracted from a domain-specific corpus into a ranker without the need of labeled training data. Such method should rank brands (e.g. sprite) higher than types (e.g. lemonade). Apart from that, we also exploit knowledge induced by semi-supervised graph-based clustering for two different purposes. On the one hand, we produce an auxiliary categorization of food items according to the Food Guide Pyramid, and assume that a food item is a type when it belongs to a category unlikely to contain brands. On the other hand, we directly model the task of brand detection using seeds provided by the output of the textual ranking features. We also harness Wikipedia articles as an additional knowledge source.
In this paper, we explore different linguistic structures encoded as convolution kernels for the detection of subjective expressions. The advantage of convolution kernels is that complex structures can be directly provided to a classifier without deriving explicit features. The feature design for the detection of subjective expressions is fairly difficult and there currently exists no commonly accepted feature set. We consider various structures, such as constituency parse structures, dependency parse structures, and predicate-argument structures. In order to generalize from lexical information, we additionally augment these structures with clustering information and the task-specific knowledge of subjective words. The convolution kernels will be compared with a standard vector kernel.
In order to automatically extract opinion holders, we propose to harness the contexts of prototypical opinion holders, i.e. common nouns, such as experts or analysts, that describe particular groups of people whose profession or occupation is to form and express opinions towards specific items. We assess their effectiveness in supervised learning where these contexts are regarded as labelled training data and in rule-based classification which uses predicates that frequently co-occur with mentions of the prototypical opinion holders. Finally, we also examine in how far knowledge gained from these contexts can compensate the lack of large amounts of labeled training data in supervised learning by considering various amounts of actually labeled training sets.
In opinion mining, there has been only very little work investigating semi-supervised machine learning on document-level polarity classification. We show that semi-supervised learning performs significantly better than supervised learning when only few labelled data are available. Semi-supervised polarity classifiers rely on a predictive feature set. (Semi-)Manually built polarity lexicons are one option but they are expensive to obtain and do not necessarily work in an unknown domain. We show that extracting frequently occurring adjectives & adverbs of an unlabeled set of in-domain documents is an inexpensive alternative which works equally well throughout different domains.
Bootstrapping Supervised Machine-learning Polarity Classifiers with Rule-based Classification
(2010)
In this paper, we explore the effectiveness of bootstrapping supervised machine-learning polarity classifiers using the output of domain-independent rule-based classifiers. The benefit of this method is that no labeled training data are required. Still, this method allows to capture in-domain knowledge by training the supervised classifier on in-domain features, such as bag of words.
We investigate how important the quality of the rule-based classifier is and what features are useful for the supervised classifier. The former addresses the issue in how far relevant constructions for polarity classification, such as word sense disambiguation, negation modeling, or intensification, are important for this self-training approach. We not only compare how this method relates to conventional semi-supervised learning but also examine how it performs under more difficult settings in which classes are not balanced and mixed reviews are included in the dataset.
Though polarity classification has been extensively explored at document level, there has been little work investigating feature design at sentence level. Due to the small number of words within a sentence, polarity classification at sentence level differs substantially from document-level classification in that resulting bag-of-words feature vectors tend to be very sparse resulting in a lower classification accuracy.
In this paper, we show that performance can be improved by adding features specifically designed for sentence-level polarity classification. We consider both explicit polarity information and various linguistic features. A great proportion of the improvement that can be obtained by using polarity information can also be achieved by using a set of simple domain-independent linguistic features.