Refine
Year of publication
Document Type
- Conference Proceeding (116)
- Doctoral Thesis (17)
- Article (2)
- Book (2)
- Master's Thesis (2)
Language
- English (139) (remove)
Keywords
- Korpus <Linguistik> (29)
- Computerlinguistik (27)
- Computerunterstützte Kommunikation (24)
- Soziale Medien (21)
- Pragmatik (19)
- Linguistik (17)
- Social Media (17)
- NER (13)
- Named entity recognition (13)
- corpus linguistics (11)
Institute
Grazing animals alter natural processes by affecting ecosystems and at the same time fulfilling ecosystem functions, thus they are regarded as ecosystem engineers. Effects of grazing are mainly studied in managed systems, where grazing animals are restricted in their movement and thus limited to certain vegetation types. On the island of Asinara the grazing system is now, due to its history as agro-penitentiary, a natural grazing system with donkeys, horses, goats, mouflons and wild boars. This multitude of grazers poses a challenge for the Asinara National Park and its management. Therefore this dissertation takes an interdisciplinary approach to investigate grazing animals and their interrelations with different components of the island ecosystem to analyse their role on the island and evaluate their effects on the biodiversity. The composition and distribution patterns of the five grazing animal species have been investigated in the context of the land-cover types of the island ecosystem. In addition, the input on the vegetation through endozoochorous seed dispersal by donkeys and goats was analysed, and the impact of grazing animals on dung beetle assemblages was studied in three highly frequented vegetation units, taking into account the intensity of use by the grazing animals. The results derived from this work highlight the importance of studying grazing animals and their interrelations within an island ecosystem. Moreover, the insights given in this thesis concerning the interrelations of grazing animals with different components of the island should open up the view on grazers and their multifaceted effects on the biodiversity, thus leading to management implementations for a sound functioning of the island ecosystem as well as the conservation and maintenance of biodiversity.
According to the cognitive action architecture approach (CAA-A; Schack, 2002, 2004), mental representations play a central role in movement control, as they are hierarchically structured in long-term memory and differentiate due to expertise. By means of structural dimensional analysis - motoric (SDA-M; Schack, 2012), movements are subdivided into basic action concepts (BACs) that are related to each other, to make mental representation structures visible. The method seeks to psychometrically depict the structural dimensions of conceptually ordered motor knowledge, both case-by-case and group-specific, and has been applied to a variety of sports contexts (Land, Volchenkov, Bläsing, & Schack, 2013). Although the examination of mental representations seems promising regarding the gain of insights into the structure of movements, motor learning processes and the relation of cognitive and movement structures, research in the field of educational research has not been conducted so far. Therefore, the aim of this dissertation project is to address the main research question: What influence can the knowledge about mental representation structures of movements have in the context of physical education and the optimization processes of learning and teaching?
The research issue, research program and research questions are presented in the general introduction of this thesis (chapter 1). To answer the main research question, three different perspectives are introduced in the main part.
The first perspective focuses on the structure of motor skills and the methodological approach to acquiring the mental representation structures. The practical implementation of the SDA-M is discussed in a text-image comparison of questionnaire items (chapter 2). The study aimed at determining an appropriate item format for the use of the SDA-M in the context of physical education. In light of the findings, the use of text or combined items is recommended when applying the SDA-M to children or adolescents.
The second perspective focuses on knowledge about the mental representation structure of learners and their execution of the skill. Based on pupils’ mental representation structure, specific instructions are developed that might contribute to the optimization of movement execution (chapter 3). Results revealed that specific instructions based on pupils’ mental representation of a gymnastics skill have a positive impact on their mental representation structure and on their motor performance.
The third perspective focuses on knowledge about the mental representation structure of teachers, here represented by sports students, examining its relation with their evaluation of pupils’ movements (chapter 4). Results indicate that more structured mental representations are linked with a more precise performance evaluation. Therefore, a relation between physical education students’ mental representation structure and their evaluation of gymnastics skills can be assumed.
Conclusively, in the general discussion, the key findings are highlighted, limitations are discussed and an outlook concerning practical implications and further research is provided (chapter 5). In sum, according to the findings of this dissertation, the acquisition and analysis of the structure of mental representations might constitute an effective means of optimizing the quality of physical education and can be seen as important for improving physical education teacher training as well as motor learning processes in general.
Arthropod herbivores act as mediators for effects that cascade up and down the trophic chain. Therefore, herbivory plays an important role for driving ecosystem processes and influencing ecosystem structures and functions. Generally, ecosystem processes are mediated by interactions between organisms. The plant community composition is influenced by competitive interactions among plants, which is affected by herbivore species. Leaf area loss to insects can reduce tree growth, but alters material flows from canopies to forest soils. Therefore, the chemical quality of litter is changed (increases in nitrogen content) through enhanced nutrient cycling rates caused by herbivory.
Climate and microclimate can affect insect physiology and behaviour directly or indirectly through climate-induced changes of host plants. Temperature determines the geographical range, site and timing of activities, success of oviposition and hatching, and the duration of developmental stages of arthropod herbivores. The activity of poikilothermic insects increases with temperature, and therefore growth and consumption rates are enhanced. However, morphological and functional leaf traits that determine host plant palatability often mediate indirect environmental effects on herbivory. Leaf palatability is determined by leaf toughness, nutrients, and defence compounds. In warm environments, expected high rates of arthropod herbivory can then be suppressed by negative changes of leaf traits.
Microclimate gradients are found across the different strata of forest ecosystems. Abiotic factors change vertically between forest layers due to a micro-environmental gradient. Along the vertical gradient, microclimate is affected by the light regime, with increasing temperatures and decreasing humidity from understorey to upper canopies. Various organisms are distributed along the vertical forest gradient based on changes in environmental conditions and in the quality and quantity of available resources. Temperate deciduous forests reveal highly stratified arthropod communities with vertical and horizontal distribution patterns. Microclimatic requirements and the availability of food resources along the vertical forest gradient can reflect spatial distributions and preferences of arthropods.
This research study investigated arthropod herbivory on leaves of deciduous tree species along the vertical gradient of temperate forests. A field study with ten forests sites in Central Germany and an experimental study in greenhouses were conducted, addressing effects of microclimate and leaf traits on arthropod herbivory. Juvenile and adult individuals of Fagus sylvatica L. (European beech), the dominant deciduous tree species in Central Europe, were chosen as main research subjects. Furthermore, Acer pseudoplatanus L. (Sycamore maple) and Carpinus betulus L. (hornbeam), two frequent tree species in the forest understorey, were also surveyed.
Social media has become an integral part of numerous individuals as well as organizations, with many services being used frequently by a majority of people. Along with its widespread use, the amount of information explodes when people use these services. This demands for efficient tools as well as methods to assist data management and retrieval.
Annotating resources by keywords, known as the tagging task, is a solution to improve categorizability and findability of resources. However, tagging is a human, time-consuming task, which requires the user's focus to figure out many keywords in a short moment and manually enter them into the system. To encourage users to tag their resources more correctly and frequently, tag recommendation is adopted into the social tagging systems to suggest relevant keywords for resources.
In this thesis, we will address the problem of personalized tag recommendation for images and present ways to solve this problem by combining the advantages of the user relation with the images' content. In order to suggest tags for unobserved images, their visual contents are used to replace the index-based information of the image entity in the tagging relations. Because the limitation of low-level features does not show the "content" of images, we propose to utilize a deep learning based approach to learn high-level visual features concurrently with the scoring-tag estimator. For the tag predictor, a latent factor model or a multi-layer perceptron is selected to compute scores of tags by which the top selected tags are sorted in descending order. As a further development upon our findings, we examine the inside and outside context of images to enhance the accuracy of estimators. Regarding the image-inside context, we are motivated by the fact that objects, such as cars or cats are influential on the user's selection criteria. Regarding the image-outside context, the image's surrounding text contributes to the clarity of the image's content for different users. We consider these contextual features as a supporting part which is combined with the mainly visual representation to enhance the tag recommendation performance. Finally, as an additional technique, transfer learning is also adapted to support the proposed models to overcome the limitations of too small training data and boost up their performance. This thesis demonstrates the usefulness and versatility of deep learning approaches for tag recommendation and highlights the importance of the learned image's content in predicting personalized tags. Directions for future work include semantic enhancements to context-based representation and extensions of the content-aware approaches to different recommendation scenarios.
Automating machine learning by providing techniques that autonomously find the best algorithm, hyperparameter configuration and preprocessing is helpful for both researchers and practitioners. Therefore, it is not surprising that automated machine learning has become a very interesting field of research.
Bayesian optimization has proven to be a very successful tool for automated machine learning. In the first part of the thesis we present different approaches to improve Bayesian optimization by means of transfer learning. We present three different ways of considering meta-knowledge in Bayesian optimization, i.e. search space pruning, initialization and transfer surrogate models. Finally, we present a general framework for Bayesian optimization combined with meta-learning and conduct a comparison among existing work on two different meta-data sets. A conclusion is that in particular the meta-target driven approaches provide better results. Choosing algorithm configurations based on the improvement on the meta-knowledge combined with the expected improvement yields best results.
The second part of this thesis is more application-oriented. Bayesian optimization is applied to large data sets and used as a tool to participate in machine learning challenges. We compare its autonomous performance and its performance in combination with a human expert. At two ECML-PKDD Discovery Challenges, we are able to show that automated machine learning outperforms human machine learning experts.
Finally, we present an approach that automates the process of creating an ensemble of several layers, different algorithms and hyperparameter configurations. These kinds of ensembles are jokingly called Frankenstein ensembles and proved their benefit on versatile data sets in many machine learning challenges. We compare our approach Automatic Frankensteining with the current state of the art for automated machine learning on 80 different data sets and can show that it outperforms them on the majority using the same training time. Furthermore, we compare Automatic Frankensteining on a large-scale data set to more than 3,500 machine learning expert teams and are able to outperform more than 3,000 of them within 12 CPU hours.
Number theory is one of the oldest mathematical areas. This is perhaps one of the reasons why there are many connections between number theory and other areas inside mathematics. This thesis is devoted to some of those connections. In the first part of this thesis I describe known connections between number theory and twelve other areas, namely analysis, sequences, applied mathematics (i.e., probability theory and numerical mathematics), topology, graph theory, linear algebra, geometry, algebra, differential geometry, complex analysis, physics and computer science, and algebraic geometry. We will see that the concepts will not only connect number theory with these areas but also yield connections among themselves. In the second part I present some new results in four topics connecting number theory with computer science, graph theory, algebra, and linear algebra and analysis, respectively. [...] In the next topic I determine the neighbourhood of the neighourhood of vertices in some special graphs. This problem can be formulated with generators of subgroups in abelian groups and is a direct generalization of a corresponding result for cyclic groups. In the third chapter I determine the number of solutions of some linear equations over factor rings of principal ideal domains R. In the case R = Z this can be used to bound sums appearing in the circle method. Lastly I investigate the puzzle “Lights Out” as well as variants of it. Of special interest is the question of complete solvability, i.e., those cases in which all starting boards are solvable. I will use various number theoretical tools to give a criterion for complete solvability depending on the board size modulo 30 and show how this puzzle relates to algebraic number theory.
The Oromo people are one of the ancient Kushitic speaking indigenous peoples of Africa. According to linguistic studies, archaeological findings and their Oral history, the original home of the Oromo is believed to be the Nubian Valley of the ancient Kushitic empire. They might have organized themselves as a nation, developed their holistic culture, the gadaa, about 4000 B.C. in their original home, then moved southwards and settled in their current regions as a single independent nation. However, the Abyssinian Emperor Minilik II, who got firearms from some European Christian Kingdoms, colonized the Oromo and built the current Ethiopian empire towards the end of 19th century.
Since then the Oromo lost their independence, were economically marginalized and culturally segregated. Using this situation as an opportunity, the missionaries of Christianity and Islam expanded their religions and established their own religious institutions in Oromia. On one hand, these two new religions brought new cultural elements that could enrich the Oromo culture. On other hand, they destroyed some valuable Oromo cultural heritages preserved by the Oromo Indigenous Religion (OIR). Their mission agents did not carefully consider cultural elements that could have continued. Instead, they destroyed them indiscriminately. The OIR galmaas (worship houses) were destroyed together with Oromo cultural and symbolic objects, and were replaced by Church buildings and mosques.
The Christian missionaries and their local agents assumed the OIR to be idolatry; its feasts, rites, and ritual practices contradictory to the Bible and the Christian faith. Therefore, at the baptismal rite they changed Oromo names to foreign names and discontinued Moggaasaa (OIR child naming rite). Among the Protestant groups of Oromo Christianity (OC), the Oromo’s cultural songs and dances were regarded to be sinful and were therefore abandoned. Oromo cultural foods and drinks were also forbidden.
Against such generalized judgment on the OIR this dissertation raises a question: Are OIR elements contradictory or compatible with the OC? To answer this question, I conducted scientific research, compared OIR and OC elements, and produced this dissertation. This work identifies some identical, similar, partially similar and some differing elements in the two Oromo religions (OIR & OC). It is my hope that these findings might contribute to a religious dialogue that aims to create a peaceful religious coexistence in Oromia and beyond.
Cartel theory, being the doctrine of the cooperation between entrepreneurs of the same industry, was founded in 1883 by the Austrian Friedrich Kleinwächter. This theory, with its specific concepts, was essentially confined to the German-speaking world until World War I. Other cultural or language areas such as the Anglosphere and the Romanic countries had different terminologies and different insights into the topic: There were theories about syndicates, combinations or trusts. The peculiarities of the respective economic cultures hindered a unification of the terms, their meanings and their underlying theories up to the early 1920s. From the mid-1890s, German cartel theory had undergone several conceptual reforms and outdid its foreign-language counterparts in terms of differentiation. Until about 1910, cartel theory (besides American trust theory) had become the most respected theory on economic unions. After World War I, international cartels became needed. Since 1929, the terminology of German cartel theory became fundamental for the corresponding debates, which had taken place first at the International Economic Conference of the League of Nations in 1927. With the entry into the 1930s, the German cartel doctrine had become a scientific standard worldwide. This recognition makes it clear that German economic science was by no means in every respect ‹backward› in the interwar period, which is the current state of research. Therefore, German economics was better prepared than any other national economic discipline for the development of an ever more organized economy as evoked by the extensive cartelization and state-initiated regulation of the 1930s. So, cartel-related expertise was increasingly used in the policy of the controlled economy of the Third Reich.
The water hyacinth (Eichhornia crassipes) is one of the top ten most invasive aquatic plant species in the world. Due to its worldwide distribution, the plant has caused tremendous damage on ecosystems and human livelihoods alike. These negative impacts are especially problematic for developing countries such as Madagascar. Considering the weak economic situation of the country, using water hyacinth to generate economic profits remains the last option to manage the species. We investigated the use of water hyacinth at Lake Alaotra, the largest lake in the country. This lake and the surrounding area are of great ecological and economic relevance for Madagascar. However, the isolation of the region and poverty limit water hyacinth use only to alternatives suitable to the weak local infrastructure. The goal of this research is firstly to identify suitable water hyacinth use options according to the local conditions and to compare them with the locally used raw materials. The first part of this research identified drivers and barriers for using water hyacinth in the region according to the prevailing socioeconomic conditions. It identified especially the use of water hyacinth as raw material for fertilizers and handicrafts as suitable alternatives for Lake Alaotra. Within the second phase, water hyacinth handicrafts were produced and compared with the predominantly used traditional papyrus handicrafts regarding production path and related costs. It was found that assembling water hyacinth handicrafts was easier and faster and they could be sold at three times the sale prices of the traditional papyrus handicrafts. Within the last part, fertilizers based on water hyacinth (composts, green manure and ash) were locally produced and compared with the commonly used agricultural fertilizers NPK and cow dung. This was done by conducting a growth experiment with Chinese cabbage, a common fast-growing vegetable in the region. Additionally, the production and transportation costs of each type of fertilizer were also taken into account. The results showed high biomass gain of cabbage grown with water hyacinth composts which was also proved be cheaper than using NPK and cow dung. All in all, this research demonstrated the efficiency of water hyacinth use as compost and handicraft as a new source of income for the Alaotra region. However, the poverty and high vulnerability of the local population must be considered along the process for a successful implementation of water hyacinth use at Lake Alaotra. A participatory approach and by offering financial insurance to the farmers during the implementation phase could encourage them to test water hyacinth compost on their own fields. Due to the various external factors influencing the marketing of water hyacinth handicrafts, an intensive and sustained supervision should be provided to the craftswomen.
This work is rooted in the fields of English Literary Studies, Cultural Studies, and Jewish American Studies. It examines memory representation in exemplary works published around the millennial change by third generation Jewish American writers Jonathan Safran Foer, Shalom Auslander, and Nicole Krauss. The focus lies on the latter’s work. Symbolic characters and objects connected to memory are discerned and analyzed in detail.
