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Siegen University Library provides a free of charge repository named OPUS Siegen (OPUS = Online PUblication Server) with the purpose to publish, archive and retrieve electronical documents produced at the University of Siegen.
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You will find Open-Access-Publications from all faculties of Siegen University and from the "universi" publishing house. The University Library applies acknowledged quality standards and offers support for publishing your documents.
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Publication Open Access On the significance of information in online decision-making(2025)When making decisions, the available information plays a crucial role. In online problems, decisions must be made sequentially as information is revealed over time. This means that early choices can influence or limit future options. In this thesis we examine the impact of information in two online problems: bin stretching and the buffer minimization problem with conflicts. To assess the quality of a decision, we apply the worst-case measure known as the competitive ratio, a tool of competitive analysis. It compares the outcome of an online decision—made with partial information—to an optimal decision with complete knowledge in hindsight. For both problems we study the effect of providing the value of the optimal offline solution’s outcome in advance on the competitive ratio. The value serves as a reference scale. Bin stretching is an online load balancing problem in which items arrive one by one. For each item we must irrevocably decide in which bin we pack the item, without knowledge of future items. Given the information that all items can be packed in unit-sized bins, the goal is to minimize the maximum load over all bins. We propose a sophisticated two-phase algorithm that surpasses the natural barrier of 3/2, as long as sufficiently many bins are available. The rigorous analysis of its Performance consists of an intricate mixture of size and weight arguments. Further contributions include valuable insights into the problem’s difficulties, extending beyond the known results for smaller numbers of bins, which are based on computer search. We present various structural design constraints that any effective algorithm must adhere to and outline directions for future improvements. The buffer minimization problem with conflicts is an online scheduling Problem in which machines share a common resource. Jobs arrive sequentially but separately on the machines. Once a job is revealed its load is stored in the machine’s Input buffer. Processing a job reduces the buffer load, but conflicts between machines restrict simultaneous execution. These conflicts are modeled by a conflict graph, where an edge between a pair of machines indicates a conflict. The objective is to provide a valid schedule that respects the conflict constraints with the goal of minimizing the maximum load that is ever stored in a single buffer. A priori, the algorithm is given the information that unit-sized buffers are sufficient to process the complete input. We study the problem in the recently introduced flow model, where loads arrive as continuous flow rather than in discrete blocks. In this setting, we present tight bounds for all conflict-graphs with four vertices, except the path which has previously already been resolved, and for the family of complete graphs. For complete bipartite graphs, we recover almost tight bounds.Source Type:1 2 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Technisch-nachhaltiges Handeln als Bildungsaufgabe in der Ingenieurausbildung – Verbreitung des Leonardischen Eides über YouTube(2024-12-10)INTRODUCTION High-tech products are becoming increasingly complex and must be subject to more ecological, social and ethical values. For engineers, this means a corresponding technical competence that is also oriented towards the principle of sustainability. In the context of appropriate engineering training, the Leonardian Oath formulated by Dreher (Dreher 2015) as a professional ethos, which has been in force since 2015, should be mentioned: Any engineering education must ensure that engineers are trained to use their professional design skills to fulfill their high design responsibility based on the principles of - ethical legitimacy - sustainability and - the social controllability. The question arises as to whether it is ensured that prospective engineers position themselves on the basis of the Leonardian Oath? CENTRAL QUESTION The aim of this study is to answer the question of whether the necessary (re)focusing of technical education on the aspect of sustainable action can be promoted through the production and distribution of corresponding YouTube videos. In order to determine the status quo in technical university teaching, an exemplary curriculum study is carried out on the basis of module manuals. METHODOLOGICAL APPROACH A qualitative content analysis of selected module handbooks from technical universities is carried out to highlight the problem. Based on the deficits revealed, a six-part video series is produced and published on YouTube under the link https://www.youtube.com/@HeinzLeymann-LE. This will be evaluated both quantitatively via the number of hits (general interest) and qualitatively via the comments made (YouTube comment function and emails to the author) and the content of the interviewees. OBJECTIVE The aim is to determine whether the published videos have led to a discussion about the future of engineering education and, if so, in what way. The approaches of the interviewees in the videos to be produced in the context of the Leonardian Oath and the comments on YouTube are to be evaluated. In addition, the reach of the videos and shorts to be created should be measured. RESULT In the context of enabling engineers to act ethically in a digital working environment, the compulsory and elective subjects of three universities and three colleges were examined with regard to the categories of the principles of ethical, economic, ecological, social and sustainable legitimacy. These are differently pronounced. Examination of the six films In the context of the dissemination of the Leonardian Oath, six films were created and published on YouTube. In the quantitative acceptance of the six films, no effectiveness of the working hypothesis can be proven in the context of the number of views. It should be noted that the number of views decreases continuously from film 1 to film 6. In terms of the quantitative acceptance of the six films, the working hypothesis can be shown to be partially effective in the context of viewer loyalty. In terms of qualitative acceptance, the effectiveness of the working hypothesis is demonstrable, as the interviews and comments indicate approval of the implementa-tion of the Leonardian Oath. Analysis of the five shorts Each of the five shorts shows a higher effectiveness than the six video films in the quantitative acceptance study. However, the effect is unclear because there is only one comment in relation to the qualitative study of the five shorts, which does not allow any conclusion to be drawn in the context of the implementation of the Leonardian Oath in the engineering courses. The working hypothesis can be confirmed with regard to the number of views (quantitative) of the five shorts and the audience retention of Short 3, which is higher than normal. According to the YouTube analysis, the four other shorts do not have the usual viewer retention. Films and shorts overall For the six films, the quantitative analysis in the context of the implementation of the Leonardian Oath says less than the qualitative analysis of the comments. The reverse is true for the five shorts.Source Type: - Some of the metrics are blocked by yourconsent settings
Publication Open Access Data-driven value creation from businesses to consumers: aligning strategies to inform development and design of data-driven services(2024-12-31)Data-driven business models are increasingly changing how businesses generate value, shape customer relationships, and secure competitive advantages. In doing so, businesses face the challenge of integrating data operationally and using it strategically. At the same time, data-driven services increasingly penetrate consumers' lives, influencing and collecting data from their consumption practices. This raises the question of how data-driven services can be designed to create added value for businesses and consumers. Based on the three derived concepts of Business-Data, Consumer-Data, and Business-Consumer Alignment, this thesis addresses this interface by examining the perspectives of businesses and consumers on data-driven services. As a coordination process between business and data strategy, two research papers on Business-Data Alignment examine the challenges businesses face in developing data-driven services. Three papers focus on Consumer-Data Alignment by analyzing the way consumers interact with data-driven services and how data influences their everyday practices. In addition, two research papers develop methodological tools to support Business-Consumer Alignment as a cooperative coordination process between businesses and consumers to achieve common goals and values in designing data-driven services. This thesis bridges theory and practice by deriving action-oriented principles and tools to address strategic and operational challenges in designing data-driven services, contributing to the research domains of Information Systems, Consumer Informatics, Recommender Systems, and Reputation Systems. - Information Systems: This work expands the understanding of data-driven value creation by specifying the strategic link between business and data strategies through Business-Data Alignment. From the perspective of businesses, technical challenges, such as the integration of heterogeneous data sources, and organizational hurdles, such as a lack of data literacy, are addressed. The developed Data Service Canvas and Data Storytelling Process represent practical frameworks that support companies in strategically planning and communicating data-driven business models and services. - Consumer Informatics: This thesis examines the consumer perspective to show how data-driven services shape consumers' everyday consumption practices and how consumers can be involved as active designers of user-centered data-driven services. Concrete design principles based on consumers' needs and practices are also derived for the domains of food and mobility. - Recommender Systems: This work conducts a case study in the food domain in the Recommender Systems research area to show how personalized and value-oriented recommendations can be designed to better support critical consumption practices, such as sustainable or ethical consumption. - Reputation Systems: In the research domain of Reputation Systems, this thesis explores trust-building in the sharing economy, specifically in peer-to-peer carsharing, by examining an algorithm-based trust mechanism to complement user ratings. Evaluating a prototypical algorithm-based reputation system shows how algorithmic ratings can be made transparent and understandable and how such systems can contribute to fair and comprehensible assessments.Source Type:10 10 - Some of the metrics are blocked by yourconsent settings
Publication Open Access Tango und Comic. Zur Kulturpoetik von Discepolín und Quino im Argentinien der década infame und der década rebelde(2025)The idea for the volume emerged while contemplating Omar Gasparini's mural in the La Boca district of Buenos Aires. The resulting interest in comparing the cultural poetics of Enrique Santos Discépolo (Discepolín) and Juan Salvador Lavado (Quino) might seem paradoxical at first, as tango and comics appear to have little in common. However, this original approach ultimately proves productive, illuminating the interplay of social conflicts and popular forms of expression within Argentine history from an unusual perspective in the cultural landscape.7 4 - Some of the metrics are blocked by yourconsent settings
Publication Open Access My home is my castle: empowering consumers’ data literacy in the digital home - a case study on voice assistants(2024-10)The well-known phrase in the title of this thesis is based on the idea of one's own home as a place of security, self-determination, sovereignty, and retreat. The proliferation of IoT (Internet of Things) devices in private households and the interconnectivity of internet-enabled devices with one another and the external environment give rise to the supposition that the concept of the home may undergo a transformation. This is due to the fact that the data collected and processed by IoT devices also exerts an influence on the home. However, permanent recording often takes place in the background and unnoticed by the residents. The work for this thesis therefore was an examination of the extent to which consumers are aware of and can deal with the data collected in their households and what practices and solutions can help them overcome the uncertainties that sometimes exist. Consequently, the focus for this thesis, in particular, was on voice assistants (VAs), as on the one hand they serve as a platform in the smart home to control other devices and thus have corresponding usage data and, on the other hand, they can intentionally as well as unintentionally collect user data through their microphones as invisible and potentially "always-listening" sensors. Methodologically, the work was based on a living lab with which a design case study was conducted. Moreover, qualitative approaches were used with a mix of methods to examine consumers in terms of their data literacy and working practices, using VAs as an example. To increase their data literacy, human-centered design approaches were used to implement a tool that would increase their awareness of data, empower them in data work practices and ultimately increase their data literacy. The end result was a prototype that allows users to request, view, and explore their interactions with their VA in order to identify saved interactions and recognize their own behavioral patterns. Finally, the work done for this thesis is an important contribution to the research areas of Usable Privacy, Information Visualization, and ultimately Consumer Informatics: First, and with regard to Usable Privacy, current data access and work practices were investigated, to identify and address the barriers in data work for increasing data awareness and literacy based on identified user needs and challenges. The results showed that existing provider solutions such as apps or data access processes (in accordance with the GDPR) are complicated and only provide limited or insufficient information about the stored personal data. The derived user experience journey and the prototype to support data requests for user data (using the example of VA systems) can ultimately help companies to make it easier for their users to access data. Moreover, they can be used to provide initial approaches to making formats that are usually only machine-readable also human-readable. Furthermore, in order to promote human readability and data awareness, Information Visualization approaches were used to prepare the raw data in an understandable way. This was done to reduce the uncertainties and knowledge gaps on the part of consumers. The example of VAs was used to show that consumers were often unaware of the multitude of everyday interactions, but also of misactivations. In addition, further visualizations showed how strongly the devices of the VAs and the system as a whole are interwoven in the "home" ecosystem and everyday consumer life. Finally, the work done for this thesis contributed to the field of Consumer Informatics, as the increased data literacy resulting in particular from the aforementioned points enables consumers to regain more control and awareness over their homes and their (digital) consumption practices. Precisely because the demarcation of privacy and personal information (such as preferences, settings, and usage data) in the domestic context is made more difficult by data-collecting products and services, the approaches and solutions investigated and developed in this thesis provide promising support options for consumers. The results of the work, therefore, make an important contribution to redressing the imbalance of information and power between consumers and companies.Source Type:4 7