Multiparty interactions in dependable distributed systems

PhD ThesisWith the expansion of computer networks, activities involving computer communication are becoming more and more distributed. Such distribution can include processing, control, data, network management, and security. Although distribution can improve the reliability of a system by replicating components, sometimes an increase in distribution can introduce some undesirable faults. To reduce the risks of introducing, and to improve the chances of removing and tolerating faults when distributing applications, it is important that distributed systems are implemented in an organized way. As in sequential programming, complexity in distributed, in particular parallel, program development can be managed by providing appropriate programming language constructs. Language constructs can help both by supporting encapsulation so as to prevent unwanted interactions between program components and by providing higher-level abstractions that reduce programmer effort by allowing compilers to handle mundane, error-prone aspects of parallel program implementation. A language construct that supports encapsulation of interactions between multiple parties (objects or processes) is referred in the literature as multiparty interaction. In a multiparty interaction, several parties somehow "come together" to produce an intermediate and temporary combined state, use this state to execute some activity, and then leave the interaction and continue their normal execution. There has been a lot of work in the past years on multiparty interaction, but most of it has been concerned with synchronisation, or handshaking, between parties rather than the encapsulation of several activities executed in parallel by the interaction participants. The programmer is therefore left responsible for ensuring that the processes involved in a cooperative activity do not interfere with, or suffer interference from, other processes not involved in the activity. Furthermore, none of this work has discussed the provision of features that would facilitate the design of multiparty interactions that are expected to cope with faults - whether in the environment that the computer system has to deal with, in the operation of the underlying computer hardware or software, or in the design of the processes that are involved in the interaction. In this thesis the concept of multiparty interaction is integrated with the concept of exception handling in concurrent activities. The final result is a language in which the concept of multiparty interaction is extended by providing it with a mechanism to handle concurrent exceptions. This extended concept is called dependable multiparty interaction. The features and requirements for multiparty interaction and exception handling provided in a set of languages surveyed in this thesis, are integrated to describe the new dependable multiparty interaction construct. Additionally, object-oriented architectures for dependable multiparty interactions are described, and a full implementation of one of the architectures is provided. This implementation is then applied to a set of case studies. The case studies show how dependable multiparty interactions can be used to design and implement a safety-critical system, a multiparty programming abstraction, and a parallel computation model.Brazilian Research Agency CNPq

The Impact of Digital Technologies on Public Health in Developed and Developing Countries

This open access book constitutes the refereed proceedings of the 18th International Conference on String Processing and Information Retrieval, ICOST 2020, held in Hammamet, Tunisia, in June 2020.* The 17 full papers and 23 short papers presented in this volume were carefully reviewed and selected from 49 submissions. They cover topics such as: IoT and AI solutions for e-health; biomedical and health informatics; behavior and activity monitoring; behavior and activity monitoring; and wellbeing technology. *This conference was held virtually due to the COVID-19 pandemic

Improving Access and Mental Health for Youth Through Virtual Models of Care

The overall objective of this research is to evaluate the use of a mobile health smartphone application (app) to improve the mental health of youth between the ages of 14–25 years, with symptoms of anxiety/depression. This project includes 115 youth who are accessing outpatient mental health services at one of three hospitals and two community agencies. The youth and care providers are using eHealth technology to enhance care. The technology uses mobile questionnaires to help promote self-assessment and track changes to support the plan of care. The technology also allows secure virtual treatment visits that youth can participate in through mobile devices. This longitudinal study uses participatory action research with mixed methods. The majority of participants identified themselves as Caucasian (66.9%). Expectedly, the demographics revealed that Anxiety Disorders and Mood Disorders were highly prevalent within the sample (71.9% and 67.5% respectively). Findings from the qualitative summary established that both staff and youth found the software and platform beneficial

The Impact of Digital Technologies on Public Health in Developed and Developing Countries

This open access book constitutes the refereed proceedings of the 18th International Conference on String Processing and Information Retrieval, ICOST 2020, held in Hammamet, Tunisia, in June 2020.* The 17 full papers and 23 short papers presented in this volume were carefully reviewed and selected from 49 submissions. They cover topics such as: IoT and AI solutions for e-health; biomedical and health informatics; behavior and activity monitoring; behavior and activity monitoring; and wellbeing technology. *This conference was held virtually due to the COVID-19 pandemic

Efficient computer-aided verification of parallel and distributed software systems

The society is becoming increasingly dependent on applications of distributed software systems, such as controller systems and wireless telecommunications. It is very difficult to guarantee the correct operation of this kind of systems with traditional software quality assurance methods, such as code reviews and testing. Formal methods, which are based on mathematical theories, have been suggested as a solution. Unfortunately, the vast complexity of the systems and the lack of competent personnel have prevented the adoption of sophisticated methods, such as theorem proving. Computerised tools for verifying finite state asynchronous systems exist, and they been successful on locating errors in relatively small software systems. However, a direct translation of software to low-level formal models may lead to unmanageably large models or complex behaviour. Abstract models and algorithms that operate on compact high-level designs are needed to analyse larger systems. This work introduces modelling formalisms and verification methods of distributed systems, presents efficient algorithms for verifying high-level models of large software systems, including an automated method for abstracting unneeded details from systems consisting of loosely connected components, and shows how the methods can be applied in the software development industry.reviewe

Framework for Security Transparency in Cloud Computing

The migration of sensitive data and applications from the on-premise data centre to a cloud environment increases cyber risks to users, mainly because the cloud environment is managed and maintained by a third-party. In particular, the partial surrender of sensitive data and application to a cloud environment creates numerous concerns that are related to a lack of security transparency. Security transparency involves the disclosure of information by cloud service providers about the security measures being put in place to protect assets and meet the expectations of customers. It establishes trust in service relationship between cloud service providers and customers, and without evidence of continuous transparency, trust and confidence are affected and are likely to hinder extensive usage of cloud services. Also, insufficient security transparency is considered as an added level of risk and increases the difficulty of demonstrating conformance to customer requirements and ensuring that the cloud service providers adequately implement security obligations. The research community have acknowledged the pressing need to address security transparency concerns, and although technical aspects for ensuring security and privacy have been researched widely, the focus on security transparency is still scarce. The relatively few literature mostly approach the issue of security transparency from cloud providers’ perspective, while other works have contributed feasible techniques for comparison and selection of cloud service providers using metrics such as transparency and trustworthiness. However, there is still a shortage of research that focuses on improving security transparency from cloud users’ point of view. In particular, there is still a gap in the literature that (i) dissects security transparency from the lens of conceptual knowledge up to implementation from organizational and technical perspectives and; (ii) support continuous transparency by enabling the vetting and probing of cloud service providers’ conformity to specific customer requirements. The significant growth in moving business to the cloud – due to its scalability and perceived effectiveness – underlines the dire need for research in this area. This thesis presents a framework that comprises the core conceptual elements that constitute security transparency in cloud computing. It contributes to the knowledge domain of security transparency in cloud computing by proposing the following. Firstly, the research analyses the basics of cloud security transparency by exploring the notion and foundational concepts that constitute security transparency. Secondly, it proposes a framework which integrates various concepts from requirement engineering domain and an accompanying process that could be followed to implement the framework. The framework and its process provide an essential set of conceptual ideas, activities and steps that can be followed at an organizational level to attain security transparency, which are based on the principles of industry standards and best practices. Thirdly, for ensuring continuous transparency, the thesis proposes an essential tool that supports the collection and assessment of evidence from cloud providers, including the establishment of remedial actions for redressing deficiencies in cloud provider practices. The tool serves as a supplementary component of the proposed framework that enables continuous inspection of how predefined customer requirements are being satisfied. The thesis also validates the proposed security transparency framework and tool in terms of validity, applicability, adaptability, and acceptability using two different case studies. Feedbacks are collected from stakeholders and analysed using essential criteria such as ease of use, relevance, usability, etc. The result of the analysis illustrates the validity and acceptability of both the framework and tool in enhancing security transparency in a real-world environment

Model Checking and Model-Based Testing : Improving Their Feasibility by Lazy Techniques, Parallelization, and Other Optimizations

This thesis focuses on the lightweight formal method of model-based testing for checking safety properties, and derives a new and more feasible approach. For liveness properties, dynamic testing is impossible, so feasibility is increased by specializing on an important class of properties, livelock freedom, and deriving a more feasible model checking algorithm for it. All mentioned improvements are substantiated by experiments

Combining SOA and BPM Technologies for Cross-System Process Automation

This paper summarizes the results of an industry case study that introduced a cross-system business process automation solution based on a combination of SOA and BPM standard technologies (i.e., BPMN, BPEL, WSDL). Besides discussing major weaknesses of the existing, custom-built, solution and comparing them against experiences with the developed prototype, the paper presents a course of action for transforming the current solution into the proposed solution. This includes a general approach, consisting of four distinct steps, as well as specific action items that are to be performed for every step. The discussion also covers language and tool support and challenges arising from the transformation

Modelo de planificación y ejecución concurrente para la composición de servicios web semánticos en entornos parcialmente observables

Los servicios Web (SW) son componentes de software que pueden ser expuestos sobre Internet e invocados a través de protocolos estándar. Incorporar semánticas a los SW, tiene como objetivo describir los aspectos semánticos, además de los sintácticos de los propios servicios. Tales descripciones permiten a los componentes de software interactuar automáticamente a fin de lograr determinadas tareas sobre los servicios, entre las que se destaca la composición de servicios en servicios más complejos. Grandes esfuerzos se realizan en este campo de la composición, pero a pesar de lo exitosas que puedan ser las aproximaciones planteadas a la fecha, aún se caracterizan por no enfrentar conjuntamente algunos factores inherentes a la Web: el ser un entorno parcialmente observable, el comportamiento incierto de los servicios y las restricciones de tiempo en las respuestas de composición. Un promisorio enfoque orientado a este fin, es el liderado por la comunidad de la Inteligencia Artificial (IA), la cual enfrenta la composición de servicios Web mediante la aplicación de técnicas de planificación IA. Es así como en este trabajo de tesis de doctorado, se propone un modelo que permita llevar a cabo la composición automática de Servicios Web Semánticos (SWS), integrando concurrentemente procesos de planificación y ejecución con restricciones de tiempo. De esta forma, se adquiere progresivamente solo la información esencialmente requerida del estado actual de la Web limitando la respuesta (un plan de composición), a un período de tiempo especificado, superando conjuntamente, dificultades propias del dominio del problema como las antes mencionadas. / Abstract. Web Services (WS) can be defined as software components that can be exposed and called on the Internet using standard communication protocols. To include semantic mechanisms in WS is aim at describing semantics aspects of the services as well as syntactic ones. Such kinds of descriptions allow software components automatically interact in order to achieve certain tasks applied on services, among which, it should be highlighted the composition of services to obtain more complex services. Great efforts have already being made within the WS composition field, but in spite of those successful approaches that can be raised to date; they are still characterized for being unaware of some key issues inherent to the Web: the fact to be a partially observable environment, the services’ uncertain behavior, and time constraints related to WS composition responses. A promising approach aimed at this purpose is headed by the Artificial Intelligence (AI) community that faces the WS composition based on the application of AI planning techniques. Thus, in this doctoral thesis dissertation, a model to perform the automatic composition of Semantic Web Services (SWS) is proposed which concurrently integrates AI planning and execution processes under time constraints. In this way, this model gradually acquires only the required essential information of the Web’s current state, and restricts the response (a composition plan) to a given time period, overcoming together, those difficulties inherent to the problem domain as mentioned above.Maestrí