Automating SLA-Driven API Development with SLA4OAI

The OpenAPI Specification (OAS) is the de facto standard to describe RESTful APIs from a functional perspective. OAS has been a success due to its simple model and the wide ecosystem of tools supporting the SLA-Driven API development lifecycle. Unfortunately, the current OAS scope ignores crucial information for an API such as its Service Level Agreement (SLA). Therefore, in terms of description and management of non-functional information, the disadvantages of not having a standard include the vendor lock-in and prevent the ecosystem to grow and handle extra functional aspects. In this paper, we present SLA4OAI, pioneering in extending OAS not only allowing the specification of SLAs, but also supporting some stages of the SLA-Driven API lifecycle with an open-source ecosystem. Finally, we validate our proposal having modeled 5488 limitations in 148 plans of 35 real-world APIs and show an initial interest from the industry with 600 and 1900 downloads and installs of the SLA Instrumentation Library and the SLA Engine.Ministerio de Economía y Competitividad TIN2015-70560-RMinisterio de Ciencia, Innovación y Universidades RTI2018-101204-B-C21Ministerio de Educación, Cultura y Deporte FPU15/0298

Usable cryptocurrency systems

Since the introduction of Bitcoin in 2008 cryptocurrency and blockchain technology have drawn increasing attention from research and industry alike. The probably most visible evidence of the growing adoption of cryptocurrencies is the combined market capitalization which had reached over USD 2.9 trillion in November 2021. While the market capitalization remains subject to high volatility and has fallen since, the field has been growing steadily behind the scenes. Developer activity has been growing over the last decade and multiple projects which had been started to improve over the original design have reached maturity in recent years. However, the introduction of new technologies is often accompanied by the emergence of equally new design challenges. Despite the technological progress over the past years, cryptocurrencies have earned a reputation of being hard to get started with and overall difficult to use. But what exactly are the aspects that make them difficult to use? How do users manage their cryptocurrency in practice? Which challenges do they need to overcome? And how can Human-Computer Interaction help overcome these challenges? In several studies, this dissertation addresses these questions and explores them through three different approaches: (1) Cryptocurrency in Human-Computer Interaction: By systematically reviewing published Human-Computer Interaction research since the inception of Bitcoin, we organize the existing research effort and juxtapose it with the changing landscape of emerging technologies from practice to identify avenues for future research. Our results show that existing research has overwhelmingly focused on Bitcoin and Ethereum, while not addressing novel cryptocurrencies. (2) Understanding User Behavior: By exploring user behavior through multiple lenses we shed light on real-world practices of users and the challenges they face. We explore security and privacy practices through a qualitative interview study and triangulate the results in a delphi-study with 25 experts. We conducted an interview study to understand a particularly relevant point for the adoption of cryptocurrency – we investigate challenges first-time users face. Our results show that many usability issues are not rooted in the technical aspects of blockchain technology and can be addressed through Human-Computer Interaction research. (3) Improving Application Usability: By evaluating different approaches on how to aid the development of cryptocurrency applications we translate the findings of our empirical work into artifacts and put them to the test. Our results show that onboarding in mobile apps can improve perceived usability for first-time users under the right conditions, that Bitcoin Lightning can serve as a usable settlement layer for everyday transactions, that education can support the next generation of developers in building more useful applications, and that systems for rapid interface prototyping may speed up development efforts. Collectively, the contribution of this dissertation centers around the ongoing discussion on how to build usable cryptocurrency systems. More precisely, this dissertation contributes (a) empirical studies that show how users manage their cryptocurrency in practice and which challenges they face in doing so and (b) constructive approaches attempting to support the development of cryptocurrency systems in the future. The work concludes by reflecting on the future role of Human-Computer Interaction research in the cryptocurrency and blockchain space

API diversity for microservices in the domain of connected vehicles

Web services in the domain of connected vehicles are subject to various requirements including high availability and large workloads. Microservices are an architectural style which can fulfill those requirements by fostering the independence and decoupling of software components as reusable services. To achieve this independence, microservices have to implement all aspects of providing the services themselves, including different API technologies for heterogeneous consumers and supporting features like authentication. In this work, we examine the use of a service proxy that externalizes these concerns into a sidecar that provides multiple APIs and common service functionality in a platform-independent manner. We look at how different kinds of API styles and technologies solve selected classes of problems and how we can translate between API technologies. We design and implement a framework for building gateways that enables the creation and composition of reusable components, in the fashion of Lego bricks, to maximize flexibility, while reducing the effort for building gateway components. We design and implement selected components of common and reusable API functionality enabling us to build a reference setup with a service proxy as a sidecar using our framework. Finally, we evaluate the proposed solution to identify benefits and drawbacks of the approach of using our framework as a service proxy. We conclude that the examined approach provides benefits for the development of many polyglot microservices, but splitting one service into two components adds additional complexity that has to be managed.Web Services für vernetzte Fahrzeuge unterliegen unterschiedlichen Anforderungen, unter anderem einer hohen Verfügbarkeit und einem großen Datendurchsatz. Microservices sind ein Architekturstil, der diesen Anforderungen gerecht werden kann, indem er die Unabhängigkeit und Entkopplung von Softwarekomponenten als wiederverwendbare Services fördert. Zum Erreichen der Unabhängigkeit implementieren Microservices alle Aspekte der Servicebereitstellung eigenständig. Dazu gehört verschiedene API Technologien für heterogene Clients bereitzustellen und unterstützende Funktionalität wie Authentifizierung zu implementieren. In dieser Arbeit wird die Verwendung einer Proxy Komponente vor einem Service untersucht, durch welche die Bereitstellung verschiedener API Technologien und allgemeiner unterstützender Funktionalität aus dem Service extrahiert wird. Die Lösungen verschiedener API Technologien und Stile für ausgewählte Klassen an Problemen werden verglichen und mögliche Umwandlungen der verschiedenen API Technologien werden untersucht. Es wird ein Framework konzeptioniert und implementiert, das die Erstellung von Gateways durch Kombination von wiederverwendbaren Komponenten, wie das Zusammensetzen von Legosteinen, ermöglicht. Dieses Framework sorgt für eine hohe Flexibilität, während es den Aufwand bei der Erstellung von Gateways gering hält. Es werden ausgewählte wiederverwendbare Komponenten entworfen, um eine Referenzimplementierung des Ansatzes umzusetzen, bei der allgemeine Funktionalität in einen parallel laufenden Proxy ausgelagert wird. Dieser Ansatz wird evaluiert, indem Vor- und Nachteile anhand eines mit dem Framework erstellten Proxys identifiziert werden. Das Fazit dieser Arbeit ist, dass dieser Ansatz bei Systemen mit vielen Microservices mit unterschiedlichen Programmiersprachen Vorteile bringt, aber die Trennung eines Services in zwei Komponenten eine nicht unerhebliche Komplexität einführt

An Approach Toward Implementing Continuous Security In Agile Environment

Traditionally, developers design software to accomplish a set of functions and then later add—or do not add—security measures, especially after the prevalence of the agile software development model. Consequently, there is an increased risk of security vulnerabilities that are introduced into the software in various stages of development. To avoid security vulnerabilities, there are many secure software development efforts in the directions of secure software development lifecycle process. The purpose of this thesis is to propose a software security assurance methodology and integrate it into the Msg Life organization’s development lifecycle based on security best practices that fulfill their needs in building secure software applications. Ultimately, the objective adhered to increasing the security maturity level according to the suggested security assurance roadmap and implemented partly in the context of this thesis.Tradicionalmente, os desenvolvedores projetam o software para realizar um conjunto de funções e, posteriormente, adicionam - ou não - medidas de segurança, especialmente após a prevalência do modelo de desenvolvimento ágil de software. Consequentemente, há um risco aumentado de vulnerabilidades de segurança que são introduzidas no software em vários estágios de desenvolvimento. Para evitar vulnerabilidades de segurança, existem muitos esforços no desenvolvimento de software nas direções dos processos do ciclo de vida desse mesmo software. O objetivo desta tese é propor uma metodologia de garantia de segurança de software e integrá-la ao ciclo de vida de desenvolvimento da Msg Life Company, com base nas melhores práticas de segurança que atendem às suas necessidades na criação de aplicativos de software seguros. Por fim, o objetivo aderiu ao aumento do nível de maturidade da segurança de acordo com o roteiro sugerido de garantia de segurança e implementado parcialmente no contexto desta tese

Smart Community Wireless Platforms: Costs, Benefits, Drawbacks, Risks

A wireless network covering most of the city is a key component of a smart city. Although the wireless network offers many benefits, a key issue is the costs associated with laying out the infrastructure and services, making the bandwidth available and maintaining the services. We believe community involvement is important in building city-wide wireless networks. Indeed, many community wireless networks have been successful. Could the city inspire and assist the communities with building their wireless networks, and then unite them for a city-wide wireless network? We address the first question by presenting a model where municipality, communities and smart utility providers work together to create a platform, smart community wireless platform, for a community where platform sides work together toward achieving smart community objectives. One challenge is to estimate the total cost, benefits and drawbacks of such platforms. Another challenge is to model risks and mitigation plans for their success. We examine relevant dynamics in measuring the total cost, benefits, drawbacks and risks of smart community wireless platforms and develop models for estimating their success under various scenarios. To develop models, we use an intelligence framework that incorporates systems dynamics modelling with statistical, economical and machine learning methods

From model-driven software development processes to problem diagnoses at runtime

Following the “convention over configuration” paradigm, model-driven software development (MDSD) generates code to implement the “default” behaviour that has been specified by a template separate from the input model. On the one hand, developers can produce end-products without a full understanding of the templates; on the other hand, the tacit knowledge in the templates is subtle to diagnose when a runtime software failure occurs. Therefore, there is a gap between templates and runtime adapted models. Generalising from the concrete problematic examples in MDSD processes to a model-based problem diagnosis, the chapter presents a procedure to separate the automated fixes from those runtime gaps that require human judgments

Attribute based component design: Supporting model driven development in CbSE

In analysing the evolution of Software Engineering, the scale of the components has increased, the requirements for different domains become complex and a variety of different component frameworks and their associated models have emerged. Many modern component frameworks provide enterprise level facilities and services, such as instance management, and component container support, that allow developers to apply if needed to manage scale and complexity. Although the services provided by these frameworks are common, they have different models and implementation. Accordingly, the main problem is, when developing a component based application using a component framework, the design of the components becomes tightly integrated with the framework implementation and the framework model is embedded in the component functionality, and hence reduces reusability. Another problem arose is, the designers must have in-depth knowledge of the implementation of a component framework to be able to model, design and implement the components and take advantages of the services provided. To address these problems, this research proposes the Attribute based Component Design (AbCD) approach which allows developers to model software using logical and abstract components at the specification level. The components encapsulate the provided functionality, as well as the required services, runtime requirements and interaction models using a set of attributes. These attributes are systemically derived by grouping common features and services from light weight component frameworks and heavy weight component frameworks that are available in the literature. The AbCD approach consists of the AbCD Meta-model, which is an extension of the บML meta-model, and the Component Design Guidelines (CDG) that includes core Component based Software Engineering principles to assist the modelling process for designers. To support the AbCD approach, an implementation has been developed as a set of plug-ins, called the AbCD tool suite, for Eclipse IDE. An evaluation of the AbCD approach is conducted by using the tool suite with two case studies. The first case study focuses on abstraction achieved by the AbCD approach and the second focuses on reusability of the components. The evaluation shows that the artefacts produced using the approach provide an alternative architectural view to the design and help to re-factor the design based on aspects. At the same time the evaluation process identified possible improvements in the AbCD meta-model and the tool suite constructed. This research provides a non-invasive approach for designing component based software using model driven development

The Software Vulnerability Ecosystem: Software Development In The Context Of Adversarial Behavior

Software vulnerabilities are the root cause of many computer system security fail- ures. This dissertation addresses software vulnerabilities in the context of a software lifecycle, with a particular focus on three stages: (1) improving software quality dur- ing development; (2) pre- release bug discovery and repair; and (3) revising software as vulnerabilities are found. The question I pose regarding software quality during development is whether long-standing software engineering principles and practices such as code reuse help or hurt with respect to vulnerabilities. Using a novel data-driven analysis of large databases of vulnerabilities, I show the surprising result that software quality and software security are distinct. Most notably, the analysis uncovered a counterintu- itive phenomenon, namely that newly introduced software enjoys a period with no vulnerability discoveries, and further that this “Honeymoon Effect” (a term I coined) is well-explained by the unfamiliarity of the code to malicious actors. An important consequence for code reuse, intended to raise software quality, is that protections inherent in delays in vulnerability discovery from new code are reduced. The second question I pose is the predictive power of this effect. My experimental design exploited a large-scale open source software system, Mozilla Firefox, in which two development methodologies are pursued in parallel, making that the sole variable in outcomes. Comparing the methodologies using a novel synthesis of data from vulnerability databases, These results suggest that the rapid-release cycles used in agile software development (in which new software is introduced frequently) have a vulnerability discovery rate equivalent to conventional development. Finally, I pose the question of the relationship between the intrinsic security of software, stemming from design and development, and the ecosystem into which the software is embedded and in which it operates. I use the early development lifecycle to examine this question, and again use vulnerability data as the means of answering it. Defect discovery rates should decrease in a purely intrinsic model, with software maturity making vulnerabilities increasingly rare. The data, which show that vulnerability rates increase after a delay, contradict this. Software security therefore must be modeled including extrinsic factors, thus comprising an ecosystem

How to Certify Machine Learning Based Safety-critical Systems? A Systematic Literature Review

Context: Machine Learning (ML) has been at the heart of many innovations over the past years. However, including it in so-called 'safety-critical' systems such as automotive or aeronautic has proven to be very challenging, since the shift in paradigm that ML brings completely changes traditional certification approaches. Objective: This paper aims to elucidate challenges related to the certification of ML-based safety-critical systems, as well as the solutions that are proposed in the literature to tackle them, answering the question 'How to Certify Machine Learning Based Safety-critical Systems?'. Method: We conduct a Systematic Literature Review (SLR) of research papers published between 2015 to 2020, covering topics related to the certification of ML systems. In total, we identified 217 papers covering topics considered to be the main pillars of ML certification: Robustness, Uncertainty, Explainability, Verification, Safe Reinforcement Learning, and Direct Certification. We analyzed the main trends and problems of each sub-field and provided summaries of the papers extracted. Results: The SLR results highlighted the enthusiasm of the community for this subject, as well as the lack of diversity in terms of datasets and type of models. It also emphasized the need to further develop connections between academia and industries to deepen the domain study. Finally, it also illustrated the necessity to build connections between the above mention main pillars that are for now mainly studied separately. Conclusion: We highlighted current efforts deployed to enable the certification of ML based software systems, and discuss some future research directions.Comment: 60 pages (92 pages with references and complements), submitted to a journal (Automated Software Engineering). Changes: Emphasizing difference traditional software engineering / ML approach. Adding Related Works, Threats to Validity and Complementary Materials. Adding a table listing papers reference for each section/subsection