Until now infrequent terms have been neglected in searching in order to save time and memory. With the help of a cascaded index and the introduced algorithms, such considerations are no longer necessary. A fast and efficient method was developed in order to find all terms in the largest freely available corpus of texts in the German language by exact search, part-word-search and fuzzy search. The process can be extended to include transliterated passages. In addition, documents that contain the term with a modified spelling, can also be found by a fuzzy search. Time and memory requirements are determined and fall considerably below the requests of common search engines.

Kollaboratives Schreiben (KS) bezeichnet das gemeinsame Erstellen eines Textdokuments in einer Gruppe, deren Mitglieder zur gleichen Zeit oder an unterschiedlichen Zeiten, am gleichen oder an unterschiedlichen Orten arbeiten können. Ausgehend von einer detaillierten KS-Analyse und den daraus resultierenden Anforderungen an softwaregestützte KS-Systeme, werden zunächst typischen Entwurfsmuster für die Implementation derartiger Systeme herausgearbeitet. Im Anschluss daran werden zwei unterschiedliche Software-Architekturen entwickelt und diskutiert. Zum einen ist dies eine Erweiterung des etablierten Protokollstandards WebDAV um eine auf Textabschnitten basierende Synchronisation, zum anderen eine idealtypische Architektur für ein neu zu entwickelndes KS-System, welche im Gegensatz zu herkömmlichen Textverarbeitungssystem nicht nur den Text sondern ein Projekt, bestehend aus Text und dessen verknüpften bzw. begleitenden Ressourcen, in den Mittelpunkt der Kollaboration stellt. / Collaborative writing (CW) is a joint work to create a text document in a group whose members are working at different times and at different locations. Firstly, based on a detailed analysis of CW and the resulting demands on software-based CW systems, typical patterns for the implementation of such systems are identified. Subsequently, two different software architectures are developed and discussed. While the first is an extension of the established protocol standard WebDAV to include a section based text synchronization. The second is an ideal type architecture for a newly developed CW system, which in contrast to a conventional word processing system takes not only the text at the center of collaboration but a complete project consisting of text and its linked or associated resources.

General purpose Twitter sentiment analysis is a novel field that is closely related to traditional Twitter sentiment analysis but slightly differs in some key aspects. The main difference lies in the fact that the novel approach considers the unfiltered public Twitter stream while most of the previous approaches often applied various filtering steps which are not feasible for many applications. Another goal is to yield more reliable results by only classifying a tweet as positive or negative if it distinctly consists of the respective sentiment and mark the remaining messages as uncertain. Traditional approaches are often not that strict. Within the course of this thesis it could be verified that the novel approach differs significantly from the traditional approach. Moreover, the experimental results indicated that the archetypical approaches could be transferred to the new domain but the related domain data is consistently sub par when compared to high quality in-domain data. Finally, the viability of the best classification algorithm could be qualitatively verified in a real-world setting that was also developed within the course of this thesis.