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Kurzfassung
Gegenstand der hier vorgestellten Arbeit ist die Untersuchung des Einflusses der Modellbildung auf die rechnerischen Ermüdungsnachweise orthotroper Fahrbahnplatten. Dazu wurde eine orthotrope Fahrbahnplatte, die den geltenden Konstruktionsempfehlungen entspricht, mit der Software SOFiSTiK als Stabwerksmodell, Stabwerksmodell mit Schalendeckblech (kombiniertes Modell) und FE-Modell modelliert. Anschließend wurden Ermüdungsnachweise mit den Ermüdungslastmodellen (ELM) 3 und 4 für zwei Konstruktionsbereiche berechnet.
Die Ergebnisse zeigen eindeutig, dass die Modellbildung Einfluss auf die Ergebnisse der Ermüdungsnachweise für die in dieser Arbeit ausgewählte Konstruktion hat. Für möglichst genaue und plausible Nachweisergebnisse ist die Anwendung des FE-Modells in Kombination mit dem ELM 4 zu empfehlen. Ein erster grober Überblick über die Ermüdung orthotroper Fahrbahnplatten kann jedoch mit allen Berechnungsmodelle und unter Anwendung von ELM 3 erzielt werden. Entgegen den normativen Vorgaben wird in An-betracht der Ergebnisse die Durchführung von Ermüdungsnachweisen auch für Neubauprojekte empfohlen.
Schlagwörter: Modellbildung, Ermüdungsnachweis, orthotrope Fahrbahnplatten, Brü-ckenbau
The goal of this empirical study is to answer whether predictions about stock price movements can be made with the use of machine learning in the energy sector and what influence contributions from social media have on its development. To answer the research
question, the social media platforms Twitter and Reddit, in terms of the suitability of the information, were studied and evaluated. Then, the sentiments of the posts from social media were collected and used in machine learning models. The models include the Gradient Boosted Regression Tree, Multilayer Perceptron, and Long Short-Term
i Memory, which predict a subsequent day's closing stock price. The study showed that deviations from predictions of stock price movements of 1.05 % are possible and further sentiment values do not show significant positive effect on reducing the error value. The
result shows that the collected sentiments from the social media platform Twitter have no positive effect on the stock price movements within the energy industry.
Keywords: stock market, stock prediction, artificial neural networks, machine learning,
energy market, sentiment analysis
Artificial intelligence (AI) is one of the most auspicious yet controversial technologies with virtually unlimited potential to solve almost all of the existential problems humanity is facing today.1 Huge resources are poured into the development, testing and application of AI that is supposed to be utilized in almost all areas of everyday life.2 It may be used to combat genetically inherited diseases, to revolutionize the economy, to bring prosperity and equality to everyone and to counter the effects of climate change.3 With AI as the enabling technology humanity may experience a better future. Today, AI capabilities can already drastically improve analytic processing tasks and algorithmic systems and have beaten humans in games such as chess.4 Yet, AI and all of its applications bring about a myriad of ethical challenges. Revolutionary weapon systems that achieve autonomy via AI and genome-editing powered by AI are just some specific examples.5 An omnipotent AI will be either the greatest or the vilest thing that has happened to humanity in its brief existence.6 However, even today more and more computational devices are connected to each other, spurring a huge increase in global data streams that can be used to further train and enhance AI systems.
The prowess of AI for executing analytic tasks paves the way for the use of AI in more and more applications. One of these applications, that shows great promise, is the use of AI in surveillance applications.7 AI surveillance applications are proliferating at a fast rate, with a number of appli-cations already being in use today.8 These applications are aimed at accomplishing a number of policy objectives, some are in accordance with basic human laws, some are definitely not and some
1 Cf. Hawking (2018). P. 183ff
2 Cf. Hawking (2018). P. 183ff.
3 Cf. Hawking (2018). P. 183ff.
4 Cf. Burton (2015). P. 1ff.
5 Cf. Hawking (2018). P. 183ff.
6 Cf. Hawking (2018). P. 183ff.
7 Cf. Feldstein (2019). P. 1.
8 Cf. Feldstein (2019). P. 1.
2
belong in the nebulous area in between lawful and unlawful.9 But what are lawful and unlawful uses of AI surveillance systems and what are their ethical implications?
This thesis will examine the ethical implications of AI based mass surveillance systems and try to answer the first central question, if it is possible to use AI based mass surveillance applica-tions in an ethical way. Furthermore, the thesis will attempt to answer the second central ques-tion and find out how the ethical use of AI based mass surveillance systems, if this ethical use is possible, materialize. Governmental agencies will be in the focus of this discussion, as their use of the technology may have bigger ethical challenges. Yet private companies will play a part as well. In an attempt to accomplish these two aims, the thesis will inspect the basics of ethics and possible ethical theories that can be utilized to answer the questions. Normative ethics will be stud-ied first with a focus on consequentialism and utilitarianism. To gain a deeper understanding of utilitarianism, act and rule utilitarianism will be compared. Afterwards, deontological theories will be the focus of the discussion with a concentration on deontological pluralism. Next, the mentioned theories will be evaluated, discussing advantages and weak spots of the theories, to assess which theory may serve as the ethical framework of this thesis and the subsequent answer to the two main questions.
The next step will be the establishment of the AI framework. This contains the definition of AI and a distinction of terms that are commonly used in the its environment such as automation and au-tonomy. The importance of data for AI will be discussed. Afterwards, the technological basis of AI will be outlined, discussing key concepts such as machine learning and deep learning. Addi-tionally, it will be examined how an AI learns. The possible uses of AI in general will be outlined in a brief fashion, blazing the trail to discussing the moral challenges of AI. Afterwards, the current pace of AI development will be studied.
In the chapter that follows, the use of AI in surveillance technology is going to be highlighted. The possible ways of how AI can be used for surveillance purposes are reviewed here, discussing facial
9 Cf. Feldstein (2019). P. 1.
3
and behavioral recognition systems, smart cities, smart policing, communications/data driven sur-veillance and their enabling technologies. Then, the global proliferation of AI surveillance systems is going to be outlined.
Subsequently, the accordance of AI surveillance with basic human laws and rights, such as the right to privacy, will be checked to find out if the law and the international framework of human rights allow for AI surveillance or at least have restrictions that would greenlight the use of AI surveillance technology. All the aspects of the thesis, especially including the selected ethical framework, will be combined in this last section in order to enable the adaptation of a framework that allows to find out, if AI surveillance systems can be ethically permissible while also creating insights how this ethical AI surveillance system must be engineered. To finish, the thesis will end with a conclusion.
Developing an intelligent chatbot that can imitate human-to-human interaction has become important in recent years. For this reason, many studies have been conducted to evaluate the quality of chatbots. Furthermore, various approaches and tools, such as sentiment analysis, have been created to improve the performance of chatbots.
This study examines previous research to identify the quality dimensions used to measure chatbots performance in order to develop a general chatbot assessment model that evaluates and compares chatbots quality. The developed evaluation model measures ten chatbot quality dimensions. This model is based on user experience. It requires human testers to interact with the chatbot to test its functioning and then a quantitative approach is used to collect data from user testing by conducting a survey with these testers. In this survey, they are instructed to evaluate the quality of the chatbot using a questionnaire that contains the items needed to evaluate each dimension.
This study also investigates whether sentiment analysis can improve the quality of chatbots and, if so, to identify the dimensions improved with sentiment analysis. For this reason, two chatbot versions are implemented using the Rasa framework (one that cannot detect sentiment and the other that analyzes sentiment and responds accordingly).
Following that, we used our evaluation model to evaluate and compare the two chatbot versions with two groups of participants by conducting a survey. In this survey, each group tested the functioning of one version. Then, both groups were instructed to use the items of the evaluation model to evaluate the version they tested. The goal of this survey was to evaluate the validity and reliability of the items used in the evaluation model to evaluate chatbots, and also to determine if sentiment analysis improved the chatbot quality by comparing survey results between the two groups. The results show that items used in the assessment model to evaluate chatbots are valid and reliable. The findings also indicate that sentiment analysis improves the chatbot’s quality. However, it improves the quality of some dimensions but not the majority of them.
Stress im Informatikstudium
(2020)
Einführung
Ziel der vorliegenden Thesis ist es, die Eu- und Disstressoren der Infomatikstudierenden an der Hochschule Ruhr West zu untersuchen. Hierzu sollen nach den Wünschen der neuen Beratungsstelle für den Studienstress die Studierenden befragt werden. Nachfolgend werden in der Thesis die bekannten Problematiken im Informatikstudium eingebunden. Zusätzlich sollen die Informatikstudierenden auf den Stress mit einem Cartoon-Video aufmerksam gemacht werden. Mithilfe des Videos sollen die zukünftigen Eu- und Disstressoren rechtzeitig erkannt und Hilfe an der Hochschule Ruhr West abgeholt werden.
Methode
Die Untersuchung der Stressoren wird mit einem Fokusgruppeninterview (N = 4) und mit einer Online-Fragebogenerhebung (N = 120) durchgeführt. Die Signifikanzprüfungen sind varianzanalytisch und die Abweichungen der Gruppen werden mit t-Tests und einfaktorieller ANOVA berechnet.
Ergebnisse
Die Ergebnisse zeigen Unterschiede zwischen den Stressoren in unterschiedlichen Gruppen. Vor allem in den Gruppen mit davor erworbenen Vorkenntnissen und mit verschieden bewerteten Fachkompetenzen. Insbesondere ist der Stresslevel zwischen den Geschlechtern und bei den Informatikstudierenden, die mehrmals im Studium erkrankt waren, unterschiedlich.
Schlussfolgerung
Die Ergebnisse sind für die aktuellen Stresssituationen im Informatikstudium und für die nächsten Studien relevant. Außerdem wird mit dieser Studie auch auf die Problematiken in der Informatik, wie z. B. dem Frauenmangel in der Informatik, die den Informatikstudierenden den Stress verursachen könnten, aufmerksam
gemacht.
Stationäre Rohrströmungen
(2024)
Für eine Automatisierung des Walzvorgangs von rundem Walzgut muss die Geschwindigkeit bekannt sein. Wegen der gekrümmten Oberfläche von rundem Walzgut können nicht die gleichen Verfahren wie bei flachem Walzgut verwendet werden, ohne negativen Einfluss auf die Toleranz und Sicherheit zu nehmen. Unter Berücksichtigung der Umgebung des Walzwerks wurden zwei Kantendetektoren entwickelt, die einen Puls erzeugen, dessen Dauer der Zeit entspricht, die der Anfang oder das Ende des Walzguts vom ersten bis zum zweiten Kantendetektor benötigt. Durch den bekannten Abstand zwischen der Sensoren kann auf diese Weise über die Zeit die Geschwindigkeit berechnet werden. In dieser Arbeit wurde eine Auswerteelektronik entwickelt, die diese Zeit Intervalle mit einer Auflösung von 5 ns und einer maximalen Abweichung unter 0,002 % messen kann. Sie verwendet einen Synchrongleichrichter, wodurch verrauschte Signale gemessen werden können und einen 32-Bit Timer, der mit einer 200 MHz Taktquelle betrieben wird. Um die Kantendetektoren anzuregen wurde ein DDS implementiert, der 10V Sinussignale bis zu 20 MHz generieren kann. Alle digitalen Schaltungen wurden in einem FPGA implementiert.