Refine
Document Type
- Doctoral Thesis (34) (remove)
Language
- English (34) (remove)
Is part of the Bibliography
- yes (34)
Institute
- Informatik (12)
- ESB Business School (8)
- Life Sciences (6)
- Technik (6)
- Texoversum (2)
Publisher
In modern collaborative production environments where industrial robots and humans are supposed to work hand in hand, it is mandatory to observe the robot’s workspace at all times. Such observation is even more crucial when the robot’s main position is also dynamic e.g. because the system is mounted on a movable platform. As current solutions like physically secured areas in which a robot can perform actions potentially dangerous for humans, become unfeasible in such scenarios, novel, more dynamic, and situation aware safety solutions need to be developed and deployed.
This thesis mainly contributes to the bigger picture of such a collaborative scenario by presenting a data-driven convolutional neural network-based approach to estimate the two-dimensional kinematic-chain configuration of industrial robot-arms within raw camera images. This thesis also provides the information needed to generate and organize the mandatory data basis and presents frameworks that were used to realize all involved subsystems. The robot-arm’s extracted kinematic-chain can also be used to estimate the extrinsic camera parameters relative to the robot’s three-dimensional origin. Further a tracking system, based on a two-dimensional kinematic chain descriptor is presented to allow for an accumulation of a proper movement history which enables the prediction of future target positions within the given image plane. The combination of the extracted robot’s pose with a simultaneous human pose estimation system delivers a consistent data flow that can be used in higher-level applications.
This thesis also provides a detailed evaluation of all involved subsystems and provides a broad overview of their particular performance, based on novel generated, semi automatically annotated, real datasets.
Advancements in Internet of Things (IoT), cloud and mobile computing have fostered the digital enrichment—or “digitization”—of physical products, which are gaining increasing relevance in practice. According to recent studies, global IoT spending will exceed USD 1 Trillion by 2021 and there will be over 25 billion IoT connections (KPMG, 2018). Porter and Heppelmann (2014) state that IT is “revolutionizing products [as …] IT is becoming an integral part of the product itself.” Senior business executives like GE’s former CEO Jeff Immelt (2015) are even proposing that “every industrial company in the coming age is also going to become a software and analytics company.” This reflects the increasing relevance of IT components’ (i.e., software, data analytics, cloud computing) integration into previously purely physical products. We call IT-enriched physical products, “digitized” products to differentiate them from purely intangible “digital” products, such as digital music, e-books, and software. Examples of digitized products include the Philips Hue smartphone-controllable lightbulb, Audi Connect internet-connected cars, or Rolls-Royce’s sensor-enabled pay per use jet engines.
Digitized products provide their producers with a wide range of opportunities to offer new functionality and product capabilities (e.g., autonomy) that traditional, physical products do not exhibit (Porter and Heppelmann, 2014). In addition, the digitization of products allows producers to continuously repurpose their offerings, by extending and/or changing the product functionality and, thus, enabling new value creation opportunities. Based on their re-programmability and connectivity, digitized products “remain essentially incomplete […] throughout their lifetime as users continue to add and delete […] and change […] functional capabilities” (Yoo, 2013). For instance, the Philips Hue connected lightbulb enables remote control of basic functions (e.g., switching on and off the light) as well as setting more advanced light scenes for day-to-day tasks (e.g., relax, read) via Amazon’s Alexa artificial intelligence assistant (Signify, 2019), offerings that were not intended use cases when Signify (previously known as Philips Lighting) created Hue in 2012. Thus, digitized products present limitless potentials for new functionality and unforeseen use cases, which provides them with a huge innovation capacity.
Despite the limitless potentials offered by digitized products, there has been a slow uptake of digitized products by businesses so far (Jernigan et al., 2016; Mocker et al., 2019). According to a 2016 MIT Sloan Management Review report (Jernigan et al., 2016) only 24% of the investigated firms were actively using IoT technologies – a key technology for digitized products. In a more recent research study Mocker et al. (2019) found that the median revenue share from digital offerings (i.e., solutions based on IT enriched products) in large companies only accounted for 5% of the total revenue of the investigated companies.
The slow uptake of digitized products might be explained by the challenges that firms face regarding the changing nature of digitized products. Pervasive digital technologies (such as IoT) change the nature of products by adding new functionality that was previously not part of the value proposition of the products/services (e.g., a pair of shoes embedded with sensors and connectivity allows joggers to have access to data regarding their run distance, speed, etc.) (Yoo et al., 2012). The addition of new functionality and use cases of digitized products makes it harder for producers to design and develop relevant products (Hui 2014). As described in the paper ‘Do Your Customers Actually Want a “Smart” Version of Your Product?’, “just because [firms] can make something with IoT technology doesn’t mean people will want it.” (Smith, 2017).
The shift in digitized products’ nature poses new challenges for producers along the entire product development process (Porter and Heppelmann, 2015; Yoo et al., 2012) and create a paradox in product digitization, described by Yoo et al. (2012) as the paradox of pace: while technology accelerates the rate of innovation, companies need to spend more time to digitize their products, extending time to market. The production of these digitized products also becomes more challenging, e.g., as companies need to deal with different clock-speeds of software and hardware development (Porter and Heppelman, 2015). The above-mentioned challenges suggest that producers need to better understand how they can generate value from their digitized products’ generative potentials.
The body of literature on digitized products has been growing in recent years. For instance, Herterich et al. (2016) investigate how digitized product affordances (i.e., potentials) enable industrial service innovation; Nicolescu et al. (2018) explore the emerging meanings of value associated with IoT; and Benbunan-Fich (2019) studies the impact of basic wearable sensors on the quality of the user experience. However, it remains unclear what it takes for firms to generate value with their digitized product potentials. This dissertation investigates this research gap.
The digital age makes it possible to be globally networked at any time. Digital communication is therefore an important aspect of today’s world. Hence, the further development and expansion of this is becoming increasingly important. Even within a wireless system, copper channels are important as part of the overall network. Given the need to keep pushing at the current limitations, careful design of the cables in connection with an adapted coding of the bits is essential to transmit more and more data.
One of the most popular and widespread cabling technologies is symmetrical copper cabling [1, pp. 8-15]. It is also known as Twisted Pair and it is of immense importance for the cabling of communication networks.
At the time of writing this thesis, data rates of up to 10 GBit/s over a transmission distance of 100 m and 40 GBit/s over a transmission distance of 30 m are standardized for symmetrical copper cabling [2]. Other lengths are not standardized. Short lengths in particular are of great interest for copper cables, because copper cables are usually used for short distances, such as between computers and the campus network or within data centres.
This work has focused on the transmission of higher order Pulse Amplitude Modulation and the associated transmission performance. The central research question is:“how well can we optimize the transmission technique in order to be able to maximise the data bandwidth over Ethernet cable and, given that remote powering is also a significant application of these cables, how much will the resulting heating affect this transmission and what can be done to mitigate that?”
To answer this question, the cable parameters are first examined. A series of spectral measurements, such as Insertion Loss, Return Loss, Near End Crosstalk and Far End Crosstalk, provide information about the electromagnetic interference and the influence of the ohmic resistance on the signal. Based on these findings, the first theoretical statements and calculations can be made. In the next step, data transmissions over different transmission lengths are realized. The examination of the eye diagrams of the different transmission approaches ultimately provides information about the signal quality of the transmissions. An overview of the maximum transmission rate depending on the transmission distance shows the potential for different applications.
Furthermore, the simultaneous transmission of energy and data is a significant advantage of copper. However, the resulting heat development has an influence on the data transmission. Therefore, the influence of the ambient temperature of cables is investigated in the last part and changes in the signal quality are clarified.
The targeted design of monodisperse, mesoporous silica microspheres (MPSMs) as HPLC separation phases is still a challenge. The MPSMs can be generated via a multi-step template-assisted method. However, this method and the factors affecting the individual process steps and resulting material properties are scarcely understood, and specific control of the complex multi-step process has been hardly discussed. In this work, the key synthesis steps were systematically investigated by means of statistical Design of Experiment (DoE). In particular, three steps were considered in detail: 1) the synthesis of porous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) (p(GMA-co-EDMA)) particles, which as template particles, determine the structure for the final MPSMs. In this context, functional models were generated, which allow the control of the template properties pore volume, pore size and specific surface area. 2) In the presence of amino-functionalized template particles, the sol-gel process was carried out under Stöber process conditions. The water to tetraethyl orthosilicate (TEOS) ratio, as well as the concentration of ammonia as basic catalyst were varied according to a face-centered central composite design (FCD). The incorporation of silica nanoparticles (SNPs) into the pore network of the porous polymers was investigated by scanning electron microscopy (SEM), evaluation of the pore properties assessed by nitrogen sorption measurements and determination of the inorganic content by thermogravimetric analysis (TGA). Here, the material properties, such as the amount of attached silica, can be specifically controlled in the resulting organic/silica hybrid material (hybrid beads, HBs). Furthermore, depending on the sol-gel conditions three, potentially four, reaction regimes were identified, leading to different HBs. These range from porous polymer particles coated with a thin protective silica layer, to interpenetrating networks of polymer and silica, to potential particles consisting of a porous polymer core coated with a silica shell. Also, the effects of the use of different precursors and solvents on silica incorporation were investigated. 3) To obtain MPSMs from the HBs, the organic polymer template was removed by calcination. The effects of sol-gel process conditions on the resulting MPSMs were evaluated and relationships between process conditions and material properties were shown in predictive models. Fully porous, spherical, monodisperse silica particles with sizes ranging from 0.5 µm to 7.8 µm and pore sizes from 3.5 nm to 72.4 nm can be prepared specifically. Subsequent to organo-functionalization, prepared MPSMs were applied as reversed-phase HPLC column materials. Here, the columns were successfully applied for the separation of proteins and amino acids. The separation performance of the materials depends largely on the property profile of the MPSMs, which is predetermined during the preparation of the HBs.
After more than three decades of electronic design automation, most layouts for analog integrated circuits are still handcrafted in a laborious manual fashion today. This book presents Self-organized Wiring and Arrangement of Responsive Modules (SWARM), a novel interdisciplinary methodology addressing the design problem with a decentralized multi-agent system. Its basic approach, similar to the roundup of a sheep herd, is to let autonomous layout modules interact with each other inside a successively tightened layout zone. Considering various principles of self-organization, remarkable overall solutions can result from the individual, local, selfish actions of the modules. Displaying this fascinating phenomenon of emergence, examples demonstrate SWARM’s suitability for floorplanning purposes and its application to practical place-and-route problems. From an academic point of view, SWARM combines the strengths of procedural generators with the assets of optimization algorithms, thus paving the way for a new automation paradigm called bottom-up meets top-down.
A distinctive highlight of the dissertation at hand is the investigation of multiple apparel supply chain actors incorporating the views of a global apparel retailer in Europe and multiple suppliers in Vietnam and Indonesia.
More specifically, the dissertation presents a coherent investigation starting with the depiction of a conceptual framework for social management strategies as a means for social risk management (SRM), exclusively aiming at the apparel industry. In accordance to the identified research gaps and suggested research directions from the conceptual framework, the role of the apparel sourcing agent for social management strategies was analysed by conducting a multiple case study approach with evidence from Vietnam and Europe, ultimately suggesting ten propositions. Whereas a further multiple case study data collection in Vietnam, Indonesia and Europe allowed for the investigation of buyer-supplier relationships with regards to social compliance strategies by using core tenets of agency theory to interpret the findings and outline ten propositions. Based on the development of a conceptual framework on social SSCM in the apparel industry, the formulation of related 20 propositions with evidence from crucial developing (apparel sourcing) countries, and the application of agency theory which has been declared as a shortfall in this context, this thesis contributes with further grounding to SSCM theory and substantially contributes to the debate by addressing numerous research gaps.
Reconstructing 3D face shape from a single 2D photograph as well as from video is an inherently ill-posed problem with many ambiguities. One way to solve some of the ambiguities is using a 3D face model to aid the task. 3D morphable face models (3DMMs) are amongst the state of the art methods for 3D face reconstruction, or so called 3D model fitting. However, current existing methods have severe limitations, and most of them have not been trialled on in-the-wild data. Current analysis-by- synthesis methods form complex non linear optimisation processes, and optimisers often get stuck in local optima. Further, most existing methods are slow, requiring in the order of minutes to process one photograph.
This thesis presents an algorithm to reconstruct 3D face shape from a single image as well as from sets of images or video frames in real-time. We introduce a solution for linear fitting of a PCA shape identity model and expression blendshapes to 2D facial landmarks. To improve the accuracy of the shape, a fast face contour fitting algorithm is introduced. These different components of the algorithm are run in iteration, resulting in a fast, linear shape-to- landmarks fitting algorithm. The algorithm, specifically designed to fit to landmarks obtained from in-the-wild images, by tackling imaging conditions that occur in in-the-wild images like facial expressions and the mismatch of 2D–3D contour correspondences, achieves the shape reconstruction accuracy of much more complex, nonlinear state of the art methods, while being multiple orders of magnitudes faster.
Second, we address the problem of fitting to sets of multiple images of the same person, as well as monocular video sequences. We extend the proposed shape-to-landmarks fitting to multiple frames by using the knowledge that all images are from the same identity. To recover facial texture, the approach uses texture from the original images, instead of employing the often-used PCA albedo model of a 3DMM. We employ an algorithm that merges texture from multiple frames in real-time based on a weighting of each triangle of the reconstructed shape mesh.
Last, we make the proposed real-time 3D morphable face model fitting algorithm available as open-source software. In contrast to ubiquitous available 2D-based face models and code, there is a general lack of software for 3D morphable face model fitting, hindering a widespread adoption. The library thus constitutes a significant contribution to the community.
Product-Service Systems (PSS) in the fashion industry : an analysis of intra-organizational factors
(2018)
The fashion industry is a vast industry that has grown tremendously over the last decades. This growth causes significant environmental impact since the production of clothes involves high input of energy, water, chemicals and generates great volumes of waste. Even though fashion firms have started to address this challenge by adopting environmental standards, it has turned out that the sole use of eco-friendly material and new manufacturing techniques is insufficient. Instead, sustainable business models are increasingly gaining attention to solve the environmental problems. Offers to rent, swap, repair or redesign clothes are among the most prominent and promising examples. For analytical purposes, these concepts can be assigned to the growing research stream of Product-Service Systems (PSS) that shift the focus from the pure sale of a product toward complementary or substitutional service offers. This decouples customer satisfaction from material consumption, prolongs the garments' lifetime and thus diminishes both material input and appertaining waste. Besides environmental sustainability, PSS imply potential economic benefits for organizations. Particularly in highly competitive industries like the fashion industry, PSS allow firms to differentiate, better compete with cost pressure and mitigate the risk of being imitated by rivels since service is more difficult to replicate. However, fashion PSS are still mainly operated in a niche market by small firms and have yet to be anchored in the mainstream fashion industry.
This thesis studies concurrency control and composition of transactions in computing environments with long living transactions where local data autonomy of transactions is indispensable. This kind of computing architecture is referred to as a Disconnected System where reads are segregated -disconnected- from writes enabling local data autonomy. Disconnecting reads from writes is inspired by Bertrand Meyer's "Command Query Separation" pattern. This thesis provides a simple yet precise definition for a Disconnected System with a focus on transaction management. Concerning concurrency control, transaction management frameworks implement a'one concurrency control mechanism fits all needs strategy'. This strategy, however, does not consider specific characteristics of data access. The thesis shows the limitations of this strategy if transaction load increases, transactions are long lived, local data autonomy is required, and serializability is aimed at isolation level. For example, in optimistic mechanisms the number of aborts suddenly increases if load increases. In pessimistic mechanisms locking causes long blocking times and is prone to deadlocks. These findings are not new and a common solution used by database vendors is to reduce the isolation. This thesis proposes the usage of a novel approach. It suggests choosing the concurrency control mechanism according to the semantics of data access of a certain data item. As a result a transaction may execute under several concurrency control mechanisms. The idea is to introduce lanes similar to a motorway where each lane is dedicated to a certain class of vehicle with the same characteristics. Whereas disconnecting reads and writes sets the traffic's direction, the semantics of data access defines the lanes. This thesis introduces four concurrency control classes capturing the semantics of data access and each of them has an associated tailored concurrency control mechanism. Class O (the optimistic class) implements a first-committer-wins strategy, class R (the reconciliation class) implements a first-n-committers-win strategy, class P (the pessimistic class) implements a first-reader-wins strategy, and class E (the escrow class) implements a first-n-readers-win strategy. In contrast to solutions that adapt the concurrency control mechanism during runtime, the idea is to classify data during the design phase of the application and adapt the classification only in certain cases at runtime. The result of the thesis is a transaction management framework called O|R|P|E. A performance study based on the TPC-C benchmark shows that O|R|P|E has a better performance and a considerably higher commit rate than other solutions. Moreover, the thesis shows that in O|R|P|E aborts are due to application specific limitations, i.e., constraint violations and not due to serialization conflicts. This is a result of considering the semantics.
Context: Fast moving markets and the age of digitization require that software can be quickly changed or extended with new features. The associated quality attribute is referred to as evolvability: the degree of effectiveness and efficiency with which a system can be adapted or extended. Evolvability is especially important for software with frequently changing requirements, e.g. internet-based systems. Several evolvability-related benefits were arguably gained with the rise of service-oriented computing (SOC) that established itself as one of the most important paradigms for distributed systems over the last decade. The implementation of enterprise-wide software landscapes in the style of service-oriented architecture (SOA) prioritizes loose coupling, encapsulation, interoperability, composition, and reuse. In recent years, microservices quickly gained in popularity as an agile, DevOps-focused, and decentralized service-oriented variant with fine-grained services. A key idea here is that small and loosely coupled services that are independently deployable should be easy to change and to replace. Moreover, one of the postulated microservices characteristics is evolutionary design.
Problem Statement: While these properties provide a favorable theoretical basis for evolvable systems, they offer no concrete and universally applicable solutions. As with each architectural style, the implementation of a concrete microservice-based system can be of arbitrary quality. Several studies also report that software professionals trust in the foundational maintainability of service orientation and microservices in particular. A blind belief in these qualities without appropriate evolvability assurance can lead to violations of important principles and therefore negatively impact software evolution. In addition to this, very little scientific research has covered the areas of maintenance, evolution, or technical debt of microservices.
Objectives: To address this, the aim of this research is to support developers of microservices with appropriate methods, techniques, and tools to evaluate or improve evolvability and to facilitate sustainable long-term development. In particular, we want to provide recommendations and tool support for metric-based as well as scenario-based evaluation. In the context of service-based evolvability, we furthermore want to analyze the effectiveness of patterns and collect relevant antipatterns. Methods: Using empirical methods, we analyzed the industry state of the practice and the academic state of the art, which helped us to identify existing techniques, challenges, and research gaps. Based on these findings, we then designed new evolvability assurance techniques and used additional empirical studies to demonstrate and evaluate their effectiveness. Applied empirical methods were for example surveys, interviews, (systematic) literature studies, or controlled experiments.
Contributions: In addition to our analyses of industry practice and scientific literature, we provide contributions in three different areas. With respect to metric-based evolvability evaluation, we identified a set of structural metrics specifically designed for service orientation and analyzed their value for microservices. Subsequently, we designed tool-supported approaches to automatically gather a subset of these metrics from machine-readable RESTful API descriptions and via a distributed tracing mechanism at runtime. In the area of scenario-based evaluation, we developed a tool-supported lightweight method to analyze the evolvability of a service-based system based on hypothetical evolution scenarios. We evaluated the method with a survey (N=40) as well as hands-on interviews (N=7) and improved it further based on the findings. Lastly with respect to patterns and antipatterns, we collected a large set of service-based patterns and analyzed their applicability for microservices. From this initial catalogue, we synthesized a set of candidate evolvability patterns via the proxy of architectural modifiability tactics. The impact of four of these patterns on evolvability was then empirically tested in a controlled experiment (N=69) and with a metric-based analysis. The results suggest that the additional structural complexity introduced by the patterns as well as developers' pattern knowledge have an influence on their effectiveness. As a last contribution, we created a holistic collection of service-based antipatterns for both SOA and microservices and published it in a collaborative repository.
Conclusion: Our contributions provide first foundations for a holistic view on the evolvability assurance of microservices and address several perspectives. Metric- and scenario-based evaluation as well as service-based antipatterns can be used to identify "hot spots" while service-based patterns can remediate them and provide means for systematic evolvability construction. All in all, researchers and practitioners in the field of microservices can use our artifacts to analyze and improve the evolvability of their systems as well as to gain a conceptual understanding of service-based evolvability assurance.
Unter der Zielsetzung der multimodalen, ortsaufgelösten optischen Spektroskopie für die markierungsfreie Charakterisierung biologischer Materialien nach Morphologie und Chemie werden vier Themenschwerpunkte behandelt.
1. Theorie der elastischen / inelastischen Lichtstreuung und laterale Auflösung in der Mikroskopie
2. Erweiterung eines Raman Mikroskops zu einem multimodalen spektralen Imaging System (MSIS) mit Photonenmigrations-Technologie
3. Erweiterung des MSIS zu Super-Resolution Raman Mikroskopie mit einer Festkörper-Immersionslinse
4. Anwendung des entwickelten MSIS auf biologische Materialien
Service robots need to be aware of persons in their vicinity in order to interact with them. People tracking enables the robot to perceive persons by fusing the information of several sensors. Most robots rely on laser range scanners and RGB cameras for this task. The thesis focuses on the detection and tracking of heads. This allows the robot to establish eye contact, which makes interactions feel more natural.
Developing a fast and reliable pose invariant head detector is challenging. The head detector that is proposed in this thesis works well on frontal heads, but is not fully pose-invariant. This thesis further explores adaptive tracking to keep track of heads that do not face the robot. Finally, head detector and adaptive tracker are combined within a new people tracking framework and experiments show its effectiveness compared to a state-of the-art system.
Melamine Formaldehyde (MF) resins are thermosetting synthetic materials. The present work deals with the evaluation of the impregnation process, modification of resin structure and abrasion resistant applications. During the industrial process paper is impregnated by aqueous oligomers. The drying procedure and the corresponding residual volatile content is a crucial step during production, because of its influence on the later surface quality. Standard measurement routines do not differentiate between physical and chemical origin. Using TGA and DSC methods, the evaporation of water could be characterized as a clear separation of solvent evaporation and the release of water during condensation. The method could be used to upgrade current quality control as well as reaction condition tuning. According to the characteristics of duroplastic material, the formed network is very dense but also brittle. Challenging applications require highly modified resins in order to decrease the network density. Substances from bio renewable resources offer chemical possibilities for covalent crosslinking. Several substance classes have been tested for compatibility via hydroxyl groups or amines. The addition of polyols under appropriate reaction conditions showed chemical incorporation into the MF prepolymer. NMR methods have been used to characterize the resins. The synthesized polymers represent a suitable alternative for the usage in challenging furniture and flooring laminate applications. MF applications for scratch and wear resistant surfaces are commonly reinforced by multiple layer setups with inorganic particles. Fulfilling normative requirements a one sheet setup of decorative paper has been developed and tested. The incorporation of special corundum particles directly on the decorative printed paper combined with a new coating system resulted in surfaces of the requested quality for wear resistance surfaces.
After more than three decades of electronic design automation, most layouts for analog integrated circuits are still handcrafted in a laborious manual fashion today. Obverse to the highly automated synthesis tools in the digital domain (coping with the quantitative difficulty of packing more and more components onto a single chip – a desire well known as More Moore), analog layout automation struggles with the many diverse and heavily correlated functional requirements that turn the analog design problem into a More than Moore challenge. Facing this qualitative complexity, seasoned layout engineers rely on their comprehensive expert knowledge to consider all design constraints that uncompromisingly need to be satisfied. This usually involves both formally specified and nonformally communicated pieces of expert knowledge, which entails an explicit and implicit consideration of design constraints, respectively.
Existing automation approaches can be basically divided into optimization algorithms (where constraint consideration occurs explicitly) and procedural generators (where constraints can only be taken into account implicitly). As investigated in this thesis, these two automation strategies follow two fundamentally different paradigms denoted as top-down automation and bottom-up automation. The major trait of top-down automation is that it requires a thorough formalization of the problem to enable a self-intelligent solution finding, whereas a bottom-up automatism –controlled by parameters– merely reproduces solutions that have been preconceived by a layout expert in advance. Since the strengths of one paradigm may compensate the weaknesses of the other, it is assumed that a combination of both paradigms –called bottom-up meets top-down– has much more potential to tackle the analog design problem in its entirety than either optimization-based or generator-based approaches alone.
Against this background, the thesis at hand presents Self-organized Wiring and Arrangement of Responsive Modules (SWARM), an interdisciplinary methodology addressing the design problem with a decentralized multi-agent system. Its basic principle, similar to the roundup of a sheep herd, is to let responsive mobile layout modules (implemented as context-aware procedural generators) interact with each other inside a user-defined layout zone. Each module is allowed to autonomously move, rotate and deform itself, while a supervising control organ successively tightens the layout zone to steer the interaction towards increasingly compact (and constraint compliant) layout arrangements. Considering various principles of self-organization and incorporating ideas from existing decentralized systems, SWARM is able to evoke the phenomenon of emergence: although each module only has a limited viewpoint and selfishly pursues its personal objectives, remarkable overall solutions can emerge on the global scale.
Several examples exhibit this emergent behavior in SWARM, and it is particularly interesting that even optimal solutions can arise from the module interaction. Further examples demonstrate SWARM’s suitability for floorplanning purposes and its application to practical place-and-route problems. The latter illustrates how the interacting modules take care of their respective design requirements implicitly (i.e., bottom-up) while simultaneously paying respect to high level constraints (such as the layout outline imposed top-down by the supervising control organ). Experimental results show that SWARM can outperform optimization algorithms and procedural generators both in terms of layout quality and design productivity. From an academic point of view, SWARM’s grand achievement is to tap fertile virgin soil for future works on novel bottom-up meets top-down automatisms. These may one day be the key to close the automation gap in analog layout design.
Knowledge is an important resource, whose transfer is still not completely understood. The underlying belief of this thesis is that knowledge cannot be transferred directly from one person to another but must be converted for the transfer and therefore is subject to loss of knowledge and misunderstanding. This thesis proposes a new model for knowledge transfer and empirically evaluates this model. The model is based on the belief that knowledge must be encoded by the sender to transfer it to the receiver, who has to decode the message to obtain knowledge.
To prepare for the model this thesis provides an overview about models for knowledge transfer and factors that influence knowledge transfer. The proposed theoretical model for knowledge transfer is implemented in a prototype to demonstrate its applicability. The model describes the influence of the four layers, namely code, syntactic, semantic, and pragmatic layers, on the encoding and decoding of the message. The precise description of the influencing factors and the overlapping knowledge from sender and receiver facilitate its implementation.
The application area of the layered model for knowledge transfer was chosen to be business process modelling. Business processes incorporate an important knowledge resource of an organisation as they describe the procedures for the production of products and services. The implementation in a software prototype allows a precise description of the process by adding semantic to the simple business process modelling language used.
This thesis contributes to the body of knowledge by providing a new model for knowledge transfer, which shows the process of knowledge transfer in greater detail and highlights influencing factors. The implementation in the area of business process modelling reveals the support provided by the model. An expert evaluation indicates that the implementation of the proposed model supports knowledge transfer in business process modelling. The results of the qualitative evaluation are supported by the findings of a qualitative evaluation, performed as a quasi-experiment with a pre-test/post-test design and two experimental groups and one control group. Mann-Whitney U tests indicated that the group that used the tool that implemented the layered model performed significantly better in terms of completeness (the degree of completeness achieved in the transfer) in comparison with the group that used a standard BPM tool (Z = 3.057, p = 0.002, r = 0.59) and the control group that used pen and paper (Z = 3.859, p < 0.001, r = 0.72). The experiment indicates that the implementation of the layered model supports the creation of a business process and facilitates a more precise representation.
IT governance: current state of and future perspectives on the concept of agility in IT governance
(2020)
Digital transformation has changed corporate reality and, with that, corporates’ IT environments and IT governance (ITG). As such, the perspective of ITG has shifted from the design of a relatively stable, closed and controllable system of a self-sufficient enterprise to a relatively fluid, open, agile and transformational system of networked co-adaptive entities. Related to the paradigm shift in ITG, this thesis aims to conceptualize a framework to integrate the concept of agility into the traditional ITG framework and to test the effects of such an extended ITG framework on corporate performance.
To do so, the thesis uses literature research and a mixed method design by blending both qualitative and quantitative research methods. Given the poorly understood situation of the agile mechanisms within the ITG framework, the building process of this thesis’ research model requires an adaptive and flexible approach which involves four different research phases. The initial a priori research model based on a comprehensive review of the extant literature is critically examined and refined at the end of each research phase, which later forms the basis of a subsequent research phase. As a result, the final research model provides guidance on how the conceptualized framework leads to better business/IT alignment as well as how business/IT alignment can mediate the effectiveness of such an extended ITG framework on corporate performance.
The first research phase explores the current state of literature with a focus on the ITG-corporate performance association. This analysis identifies five perspectives with respect to the relationship between ITG and corporate performance. The main variables lead to the perspectives of business/IT alignment, IT leadership, IT capability and process performance, resource relatedness and culture. Furthermore, the analysis presents core aspects explored within the identified perspectives that could act as potential mediators or moderators in the relationship between ITG and corporate performance.
The second research phase investigates the agile aspect of an effective ITG framework in the dynamic contemporary world through a qualitative study. Gleaned from 46 semi-structured interviews across various industries with governance experts, the study identifies 25 agile ITG mechanisms and 22 traditional ITG mechanisms that corporations use to master digital transformation projects. Moreover, the research offers two key patterns indicating to a call for ambidextrous ITG, with corporations alternating between stability and agility in their ITG mechanisms.
In research phase three, a scale development process is conducted in order to develop the agile items explored in research phase two. Through 56 qualitative interviews with professionals the evaluation uncovers 46 agile governance mechanisms. Moreover, these dimensions are rated by 29 experts to identify the most effective ones. This leads to the identification of six structure elements, eight processes, and eight relational mechanisms.
Finally, in research phase four a quantitative research approach through a survey of 400 respondents is established to test and predict the formulated relationships by using the partial least squares structural equation modelling (PLS-SEM) method. The results provide evidence for a strong causal relationship among an expanded ITG concept, business/IT alignment, and corporate performance. These findings reveal that the agile ITG mechanisms within an effective ITG framework seem critical in today’s digital age.
This research is unique in exploring the combination of traditional and agile ITG mechanisms. It contributes to the theoretical base by integrating and extending the literature on ITG, business/IT alignment, ambidexterity and agility, all of which have long been recognized as critical for achieving organizational goals. In summary, this work presents an original analysis of an effective ITG framework for digital transformation by including the agile aspect within the ITG construct. It highlights that is not enough to apply only traditional mechanisms to achieve effective business/IT alignment in today’s digital age; agile ITG mechanisms are also needed. Therefore, a novel ITG framework following an ambidextrous approach is provided consisting of traditional ITG mechanisms as well as newly developed agile ITG practices. This thesis also demonstrates that agile ITG mechanisms can be measured independently of traditional ITG mechanisms within one causal model. This is an important theoretical outcome that allows the current state of ITG to be assessed in two distinct dimensions, offering various pathways for further research on the different antecedents and effects of traditional and agile ITG mechanisms. Furthermore, this thesis makes practical contributions by highlighting the need to develop a basic governance framework powered by traditional ITG mechanisms and simultaneously increase agility in ITG mechanisms. The results imply that corporations might be even more successful if they include both traditional and agile mechanisms in their ITG framework. In this way, the uncovered agile ITG practices may provide a template for CIOs to derive their own mechanisms in following an ambidextrous approach that is suitable for their corporation.
In today’s marketplace, the consumption of luxury goods is at a peak due to increasing global wealth and low interest rates, resulting in a vast supply of goods and services to which customer experiences are more relevant than ever before. One of the most recent developments in this field shows that consumers no longer simply purchase a product or service based on the fact sheet; they are also interested in the experience around the product. Successful brands must develop and maintain individual images to sustain their competitive advantage and build brand equity that is beneficial for customers and firms. Ideally, these will lead to satisfaction and loyalty between a brand, its products, and its customers. Existing research about brand experience and brand equity has mainly focused on functional aspects, which seem to differ for high-value luxury goods. Most studies have focused on industries like retail and fashion brands, sampling university students or visitors to shopping malls, and some have even mixed different types of industries together. This underpins the need for research within a single luxury industry with actual luxury customers who have a solid background with brand experiences.
The purpose of this study was to explore the brand experience spectrum within the automotive industry in Germany, particularly in the affordable luxury sport car sector. Identifying the factors and components that constitute, influence, or leverage/drive a brand experience from their perspective was a clear aim of the study. To achieve this, the study collected data from indepth interviews with German (n=60) respondents who had experience with affordable and luxury sport cars. The conceptual framework was based on two empirically tested models guiding this exploratory consumer research. The first model to build on was the consumerbased brand equity model, empirically tested by Çifci et al. (2016) and Nam et al. (2011). The second conceptual framework was Lemon and Verhoef’s (2016) customer journey model consisting of relevant touchpoints along the following three stages: pre-purchase, purchase, and post-purchase.
The findings of the research demonstrate that, although the six brand equity concepts – brand awareness, physical quality, staff behaviour, self-congruence, brand identification, and lifestyle – are broadly applicable in understanding customer experience in the affordable luxury car industry, the content of these dimensions differs from that suggested by the previous authors. The research established that cognitive and affective (or symbolic) components build the foundation of customer brand experience and supports Çifci et al.’s (2016) and Nam et al.’s (2011) study results. The study also identified brand trust as an important and highly relevant concept for customer brand experience in the luxury automotive car industry. Brand trust influences customer satisfaction and loyalty, therefore improving and complementing the existing model. Furthermore, the study confirmed Lemon and Verhoef’s (2016) process model of the customer journey and experience; however, it suggested two different customer journeys depending on the customers’ previous experience (first-time and experienced buyers). The differences between the two groups and the relevance of the journey touchpoints within the three purchase stages vary significantly in terms and are distinct. Identified key touchpoints for both groups are the contact to a dealer as well as information gathering online. Differences have been found in the length of purchase stages and across the customer journey. The study highlights the importance of trust, identification, and product quality for customer brand experience. Moreover, the findings of this study complement the brand equity model of Çifci et al. (2016) by adding the new concept of trust, which is highly relevant. The current knowledge is complemented by a new understanding and mapping of the customer journey for luxury sports cars in Germany. This study can assist practitioners and managers by providing a compass indicating which touchpoints are relevant to which customer group. Social value can be achieved by encouraging interactions between brand and consumer (e.g. central product launch events) and through brand-oriented interactions among consumers (e.g. dealer events, clubs, or communities). Customers are motivated to express their distinctiveness through product experience and brand identification (belonging/distinction) and to develop a loyal link to brands.
Compared to diesel or gasoline, using compressed natural gas as a fuel allows for significantly decreased carbon dioxide emissions. With the benefits of this technology fully exploited, substantial increases of engine efficiency can be expected in the near future. However, this will lead to exhaust gas temperatures well below the range required for the catalytic removal of residual methane, which is a strong greenhouse gas. By combination with a countercurrent heat exchanger, the temperature level of the catalyst can be raised significantly in order to achieve sufficient levels of methane conversion with minimal additional fuel penalty. This thesis provides fundamental theoretical background of these so-called heat-integrated exhaust purification systems. On this basis, prototype heat exchangers and appropriate operating strategies for highly dynamic operation in passenger cars are developed and evaluated.
Ever since the 1980s, researchers in computer science and robotics have been working on making autonomous cars. Due to recent breakthroughs in research and devel- opment, such as the Bertha Benz Project [ZBS+14], the goal of fully autonomous vehicles seems closer than ever before. Yet a lot of questions remain unanswered. Especially now that the automotive industry moves towards autonomous systems in series production vehicles, the task of precise localization has to be solved with automotive grade sensors and keep memory and processing consumption at a mini- mum. This thesis investigates the Simultaneous Localization and Mapping (SLAM) prob- lem for autonomous driving scenarios on a parking lot using low cost automotive sensors. The main focus is herby devoted to the RAdio Detection And Ranging (RADAR) sensor, which has not been widely analyzed in an autonomous driving scenario so far, even though they are abundant in the automotive industry for ap- plications such as Adaptive Cruise Control (ACC). Due to the high noise floor, the radar sensor has widely been disregarded in the Intelligent Transportation Systems and Robotics communities with regards to SLAM applications. However in this thesis, it is shown that the RADAR sensor proves to be an affordable, robust and precise sensor, when modeling its physical properties correctly. In this regard, a GraphSLAM based framework is introduced, which extracts features from the RADAR sensor and generates an optimized map of the surroundings using the RADAR sensor alone. This framework is used to enable crowd based localization, which is not limited to the RADAR sensor alone. By integrating an automotive Light Detection and Ranging (LiDAR) and stereo camera sensor, a robust and precise localization system can be built that that is suitable for autonomous driving even in complex parking lot scenarios. It it is thereby shown that the RADAR sensor is strongly contributing to obtaining good results in a sensor fusion setup. These results were obtained on an extensive dataset on a parking lot, which has been recorded over the course of several months. It contains different weather conditions, different configurations of parked cars and a multitude of different trajectories to validate the approaches described in this thesis and to come to the conclusion that the RADAR sensor is a reliable sensor in series autonomous driving systems, both in a multi sensor framework and as a single component for localization.
So far, only few authors addressed the serum-free, defined differentiation of adipocytes. And there are hardly any trials available on the defined maintenance of adipocytes. In this study, the development of a defined culture medium for the adipogenic differentiation of primary human adipose-derived stem cells (ASCs) was aimed. Based on the addition of specific factors for the replacement of serum, ASCs were differentiated to viable and characteristic adipocytes for 14 days, which was proven through the accumulation of lipids, the expression of perilipin A and by the release of leptin and glycerol. Furthermore, a defined maintenance medium was developed, which supported the maturation and stability of cells for a long-term period of additional 42 days until day 56.