Reference Model and Architecture for the Post-Platform Economy

The primary goal of this thesis is to propose a reference model and an accompanying software system architecture, which together can serve as a guiding framework for the analysis, design, and implementation of distributed market spaces. The benefit of such a framework is considered two-fold: On the one hand, it provides insights essential for understanding various aspects and elements of self-organized and strictly decentralized online structures to facilitate the emergence of the post-platform economy. On the other hand, it serves as a blueprint for designing and implementing a distributed marketplace instance for a specific application context. It thus allows consumers and providers to set up and expand market spaces themselves, in which they can engage directly and reliably with complex product scenarios

Space Station Freedom data management system growth and evolution report

The Information Sciences Division at the NASA Ames Research Center has completed a 6-month study of portions of the Space Station Freedom Data Management System (DMS). This study looked at the present capabilities and future growth potential of the DMS, and the results are documented in this report. Issues have been raised that were discussed with the appropriate Johnson Space Center (JSC) management and Work Package-2 contractor organizations. Areas requiring additional study have been identified and suggestions for long-term upgrades have been proposed. This activity has allowed the Ames personnel to develop a rapport with the JSC civil service and contractor teams that does permit an independent check and balance technique for the DMS

Multi-tenant hybrid cloud architecture

This paper examines the challenges associated with the multi-tenant hybrid cloud architecture and describes how this architectural approach was applied in two software development projects. The motivation for using this architectural approach is to allow developing new features on top of monolithic legacy systems – that are still in production use – but without using legacy technologies. The architectural approach considers these legacy systems as master systems that can be extended with multi-tenant cloud-based add-on applications. In general, legacy systems are run in customer-operated environments, whereas add-on applications can be deployed to cloud platforms. It is thus imperative to have a means connectivity between these environments over the internet. The technology stack used within the scope of this thesis is limited to the offering of the .NET Core ecosystem and Microsoft Azure. In the first part of the thesis work, a literature review was carried out. The literature review focused on the challenges associated with the architectural approach, and as a result, a list of challenges was formed. This list was utilized in the software development projects of the second part of the thesis. It should be noted that there were very few high-quality papers available focusing exactly on the multi-tenant hybrid cloud architecture, so, in the end, source material for the review was searched separately for multi-tenant and for hybrid cloud design challenges. This factor is noted in the evaluation of the review. In the second part of the thesis work, the architectural approach was applied in two software development projects. Goals were set for the architectural approach: the add-on applications should be developed with modern technology stacks; their delivery should be automated; their subscription should be straightforward for customer organizations and they should leverage multi-tenant resource sharing. In the first project a data quality management tool was developed on top of a legacy dealership management system. Due to database connectivity challenges, confidentiality of customer data and authentication requirements, the implemented solution does not fully utilize the architectural approach, as having the add-on application hosted in the customer environment was the most reasonable solution. Despite this, the add-on application was developed with a modern technology stack and its delivery is automated. The subscription process does involve certain manual steps and, if the customer infrastructure changes over time, these steps must be repeated by the developers. This decreases the scalability of the overall delivery model. In the second project a PDA application was developed on top of a legacy vehicle maintenance tire hotel system. The final implementation fully utilizes the architectural approach. Support for multi-tenancy was implemented using ASP.NET Core Dependency Injection and Finbuckle.MultiTenancy-library. Azure Relay Hybrid Connection was used for hybrid cloud connectivity between the add-on application and the master system. The delivery model incorporates the same challenges regarding subscription and customer infrastructure changes as the delivery model of the data quality management tool. However, the manual steps associated with these challenges must be performed only once per customer – not once per customer per application. In addition, the delivery model could be improved to support customer self-service governance, enabling the delegation of any customer environment installations to the customers themselves. Even further, the customer environment installation could potentially cover an entire product family. As an example, instead of just providing access for the PDA application, the installation could provide access for all vehicle maintenance family add-on applications. This would make customer environment management easier and developing new add-on applications faster

The integrated use of enterprise and system dynamics modelling techniques in support of business decisions

Enterprise modelling techniques support business process re-engineering by capturing existing processes and based on perceived outputs, support the design of future process models capable of meeting enterprise requirements. System dynamics modelling tools on the other hand are used extensively for policy analysis and modelling aspects of dynamics which impact on businesses. In this paper, the use of enterprise and system dynamics modelling techniques has been integrated to facilitate qualitative and quantitative reasoning about the structures and behaviours of processes and resource systems used by a Manufacturing Enterprise during the production of composite bearings. The case study testing reported has led to the specification of a new modelling methodology for analysing and managing dynamics and complexities in production systems. This methodology is based on a systematic transformation process, which synergises the use of a selection of public domain enterprise modelling, causal loop and continuous simulationmodelling techniques. The success of the modelling process defined relies on the creation of useful CIMOSA process models which are then converted to causal loops. The causal loop models are then structured and translated to equivalent dynamic simulation models using the proprietary continuous simulation modelling tool iThink

Transactions and data management in NoSQL cloud databases

NoSQL databases have become the preferred option for storing and processing data in cloud computing as they are capable of providing high data availability, scalability and efficiency. But in order to achieve these attributes, NoSQL databases make certain trade-offs. First, NoSQL databases cannot guarantee strong consistency of data. They only guarantee a weaker consistency which is based on eventual consistency model. Second, NoSQL databases adopt a simple data model which makes it easy for data to be scaled across multiple nodes. Third, NoSQL databases do not support table joins and referential integrity which by implication, means they cannot implement complex queries. The combination of these factors implies that NoSQL databases cannot support transactions. Motivated by these crucial issues this thesis investigates into the transactions and data management in NoSQL databases. It presents a novel approach that implements transactional support for NoSQL databases in order to ensure stronger data consistency and provide appropriate level of performance. The novelty lies in the design of a Multi-Key transaction model that guarantees the standard properties of transactions in order to ensure stronger consistency and integrity of data. The model is implemented in a novel loosely-coupled architecture that separates the implementation of transactional logic from the underlying data thus ensuring transparency and abstraction in cloud and NoSQL databases. The proposed approach is validated through the development of a prototype system using real MongoDB system. An extended version of the standard Yahoo! Cloud Services Benchmark (YCSB) has been used in order to test and evaluate the proposed approach. Various experiments have been conducted and sets of results have been generated. The results show that the proposed approach meets the research objectives. It maintains stronger consistency of cloud data as well as appropriate level of reliability and performance

Policy enforcement in cloud computing

Cloud Computing is an emerging technology, providing attractive way of hosting and delivering services over the Internet. Many organizations and individuals are utilizing Cloud services to share information and collaborate with partners. However, Cloud provides abstraction over the underlying physical infrastructure to the customers, that raises information security concerns, while storing data in a virtualized environment without having physical access to it. Additionally, certain standards have been issued to provide interoperability between users and various distributed systems(including Cloud infrastructures), in a standardized way. However, implementation and interoperability issues still exist and introduce new challenges. This thesis explores the feasibility of securing data in a cloud context, using existing standards and specifications, while retaining the benefits of the Cloud. The thesis provides a view on increasing security concerns of moving to the cloud and sharing data over it. First, we define security and privacy requirements for the data stored in the Cloud. Based on these requirements, we propose the requirements for an access control system in the Cloud. Furthermore, we evaluate the existing work in the area of currently available access control systems and mechanisms for secure data sharing over the Cloud, mostly focusing on policy enforcement and access control characteristics. Moreover, we determine existing mechanisms and standards to implement secure data sharing and collaborative systems over the Cloud. We propose an architecture supporting secure data sharing over the untrusted Cloud environment, based on our findings. The architecture ensures policy based access control inside and outside Cloud, while allowing the benefits of Cloud Computing to be utilized. We discuss the components involved in the architecture and their design considerations. To validate the proposed architecture, we construct the proof of concept prototype. We present a novel approach for implementing policy based access control, by achieving interoperability between existing standards and addressing certain issues, while constructing the system prototype. Furthermore, we deploy our solution in the Cloud and perform the performance tests to evaluate the performance of the system. Finally, we perform a case study by utilizing our system in a real-life scenario. To do this we slightly tailor our solution to meet specific needs. Overall, this thesis provides a solid foundation for the policy enforcement and access control mechanisms in the Cloud-based systems and motivates further work within this field. Cloud Computing is an emerging technology, providing attractive way of hosting and delivering services over the Internet. Many organizations and individuals are utilizing Cloud services to share information and collaborate with partners. However, Cloud provides abstraction over the underlying physical infrastructure to the customers, that raises information security concerns, while storing data in a virtualized environment without having physical access to it. Additionally, certain standards have been issued to provide interoperability between users and various distributed systems(including Cloud infrastructures), in a standardized way. However, implementation and interoperability issues still exist and introduce new challenges. This thesis explores the feasibility of securing data in a cloud context, using existing standards and specifications, while retaining the benefits of the Cloud. The thesis provides a view on increasing security concerns of moving to the cloud and sharing data over it. First, we define security and privacy requirements for the data stored in the Cloud. Based on these requirements, we propose the requirements for an access control system in the Cloud. Furthermore, we evaluate the existing work in the area of currently available access control systems and mechanisms for secure data sharing over the Cloud, mostly focusing on policy enforcement and access control characteristics. Moreover, we determine existing mechanisms and standards to implement secure data sharing and collaborative systems over the Cloud. We propose an architecture supporting secure data sharing over the untrusted Cloud environment, based on our findings. The architecture ensures policy based access control inside and outside Cloud, while allowing the benefits of Cloud Computing to be utilized. We discuss the components involved in the architecture and their design considerations. To validate the proposed architecture, we construct the proof of concept prototype. We present a novel approach for implementing policy based access control, by achieving interoperability between existing standards and addressing certain issues, while constructing the system prototype. Furthermore, we deploy our solution in the Cloud and perform the performance tests to evaluate the performance of the system. Finally, we perform a case study by utilizing our system in a real-life scenario. To do this we slightly tailor our solution to meet specific needs. Overall, this thesis provides a solid foundation for the policy enforcement and access control mechanisms in the Cloud-based systems and motivates further work within this field

Decentralized Open Platform for Vaccination—A German Example: COVID-19-Vacc

The COVID-19 pandemic has massively impacted the health of many people worldwide and poses significant challenges for our social, economic, and political life. Global vaccination should help the world overcome the pandemic and return to a “normal” life. In Germany, the Federal Ministry of Health presented its “National Vaccination Strategy COVID-19”, which describes the primary actors, elements, and activities required for the immunization of the German population. However, the implementation is challenging due to the federal organization of the German state in sixteen federal states. While essential processes such as vaccination rate monitoring and surveillance are planned centrally, the sixteen federal states are responsible for implementing the vaccination strategy in a decentralized manner. Furthermore, the European General Data Protection Regulation (EU-GDPR) imposes strict rules for processing and exchanging personal data. However, Germany is only a case in point. Governmental decisions always need to be implemented by regional and/or local actors, the number of which varies greatly depending on the country. This work addresses these challenges by proposing the COVID-19-Vacc Platform—an open and decentralized digital platform focused on vaccinations as a matter of example. The proposed platform model connects various actors and enables them to involve, conduct, and track the vaccination process while meeting all necessary data protection and security requirements defined by EU-GDPR. Using the DMS Reference Model as the theoretical framework, the blueprint of the COVID-19-Vacc Platform is developed, outlining the platform’s ecosystem structure, its interactions process model, and the service stack, defining how the proposed platform works on the operational level. Our COVID-19-Vacc Platform may help facilitate a fast and EU-GDPR compliant implementation of COVID-19 vaccination strategies. Beyond that, the proposed open and decentralized platform model might facilitate international interconnectivity and therefore the management of emerging global pandemics or other global health-related crisi