Refine
Year of publication
- 2020 (5) (remove)
Document Type
- Doctoral Thesis (5) (remove)
Language
- English (5) (remove)
Is part of the Bibliography
- yes (5)
Institute
- Informatik (3)
- ESB Business School (1)
- Technik (1)
Publisher
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.
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.
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.
High Performance Computing (HPC) enables significant progress in both science and industry. Whereas traditionally parallel applications have been developed to address the grand challenges in science, as of today, they are also heavily used to speed up the time-to-result in the context of product design, production planning, financial risk management, medical diagnosis, as well as research and development efforts. However, purchasing and operating HPC clusters to run these applications requires huge capital expenditures as well as operational knowledge and thus is reserved to large organizations that benefit from economies of scale. More recently, the cloud evolved into an alternative execution environment for parallel applications, which comes with novel characteristics such as on-demand access to compute resources, pay-per-use, and elasticity. Whereas the cloud has been mainly used to operate interactive multi-tier applications, HPC users are also interested in the benefits offered. These include full control of the resource configuration based on virtualization, fast setup times by using on-demand accessible compute resources, and eliminated upfront capital expenditures due to the pay-per-use billing model. Additionally, elasticity allows compute resources to be provisioned and decommissioned at runtime, which allows fine-grained control of an application's performance in terms of its execution time and efficiency as well as the related monetary costs of the computation. Whereas HPC-optimized cloud environments have been introduced by cloud providers such as Amazon Web Services (AWS) and Microsoft Azure, existing parallel architectures are not designed to make use of elasticity. This thesis addresses several challenges in the emergent field of High Performance Cloud Computing. In particular, the presented contributions focus on the novel opportunities and challenges related to elasticity. First, the principles of elastic parallel systems as well as related design considerations are discussed in detail. On this basis, two exemplary elastic parallel system architectures are presented, each of which includes (1) an elasticity controller that controls the number of processing units based on user-defined goals, (2) a cloud-aware parallel execution model that handles coordination and synchronization requirements in an automated manner, and (3) a programming abstraction to ease the implementation of elastic parallel applications. To automate application delivery and deployment, novel approaches are presented that generate the required deployment artifacts from developer-provided source code in an automated manner while considering application-specific non-functional requirements. Throughout this thesis, a broad spectrum of design decisions related to the construction of elastic parallel system architectures is discussed, including proactive and reactive elasticity control mechanisms as well as cloud-based parallel processing with virtual machines (Infrastructure as a Service) and functions (Function as a Service). To evaluate these contributions, extensive experimental evaluations are presented.
Customer orientation should be the core engine of every organisation. Information technology can be considered as the enabler to generate competitive advantages through customer processes in marketing, sales and service. The impact of information technologies is the biggest risk and at the same time a huge opportunity for any organisation. Research shows that Customer Relationship Management (CRM) enables organisations to perform better and focus more on their customers (e.g. market capitalisation of Amazon). While global enterprises are shaping the future of customer centricity and information technology, the question arises how German B2B organisations can shift their value contribution from product-centric to customer-centric. Therefore, these organisations are attempting to implement CRM software and putting their customers more into focus. However, the question remains, how organisations are approaching the implementation of CRM and if these attempts are paying off in terms of business performance.
Contributing to this highly topical discussion, this thesis contributes to the body of knowledge about the implementation of CRM in the German B2B sector and how it impacts their business performance. First, theoretical frameworks have been developed based on an extensive literature review. Hereby different aspects of CRM are worked-out and mapped against three dimensions of business performance, namely process efficiency, customer satisfaction and financial performance. Based on the theory, a conceptual framework was developed to test the relationships between CRM and Business Performance (BP). Therefore, a survey with 500 participants has been conducted. Based on this a measurement model was developed to test five main hypotheses.
The findings of these hypotheses suggest, that the implementation of CRM positively impacts business performance. In specific, the usage of analytical CRM and the establishment of a dedicated CRM success measurement correlate with the performance of German B2B organisations. In addition to these main findings, various key statements could be derived from the research and a measurement model was developed, which can be used for different organisational characteristics assessing BP. As a result, CRM implementations can be enhanced, and business performance can be improved.