High-Performance Cloud Computing: A View of Scientific Applications

Scientific computing often requires the availability of a massive number of computers for performing large scale experiments. Traditionally, these needs have been addressed by using high-performance computing solutions and installed facilities such as clusters and super computers, which are difficult to setup, maintain, and operate. Cloud computing provides scientists with a completely new model of utilizing the computing infrastructure. Compute resources, storage resources, as well as applications, can be dynamically provisioned (and integrated within the existing infrastructure) on a pay per use basis. These resources can be released when they are no more needed. Such services are often offered within the context of a Service Level Agreement (SLA), which ensure the desired Quality of Service (QoS). Aneka, an enterprise Cloud computing solution, harnesses the power of compute resources by relying on private and public Clouds and delivers to users the desired QoS. Its flexible and service based infrastructure supports multiple programming paradigms that make Aneka address a variety of different scenarios: from finance applications to computational science. As examples of scientific computing in the Cloud, we present a preliminary case study on using Aneka for the classification of gene expression data and the execution of fMRI brain imaging workflow.Comment: 13 pages, 9 figures, conference pape

Ada as a design specification language

The primary thesis objective is research into current approaches to design specification languages, emphasizing Ada. Requirements specification is touched upon. Design specification is explored and related to requirements and implementation. The role of language in design is discussed, as well as objectives of the design specification and features that a specification language should provide in order to meet those objectives. Formal language is contrasted with natural language. Some formal specification languages are described, both Ada related and not Ada related. The secondary objective, the thesis project, is to illustrate a design specification in a formal language, Ada. The purpose of the project is to compare the Ada expression of an example design with the natural language specification for the same system

Coordination in Service Value Networks - A Mechanism Design Approach

The fundamental paradigm shift from traditional value chains to agile service value networks (SVN) implies new economic and organizational challenges. This work provides an auction-based coordination mechanism that enables the allocation and pricing of service compositions in SVNs. The mechanism is multidimensional incentive compatible and implements an ex-post service level enforcement. Further extensions of the mechanism are evaluated following analytical and numerical research methods

Patterns for Providing Real-Time Guarantees in DOC Middleware - Doctoral Dissertation, May 2002

The advent of open and widely adopted standards such as Common Object Request Broker Architecture (CORBA) [47] has simplified and standardized the development of distributed applications. For applications with real-time constraints, including avionics, manufacturing, and defense systems, these standards are evolving to include Quality-of-Service (QoS) specifications. Operating systems such as Real-time Linux [60] have responded with interfaces and algorithms to guarantee real-time response; similarly, languages such as Real-time Java [59] include mechanisms for specifying real-time properties for threads. However, the middleware upon which large distributed applications are based has not yet addressed end-to-end guarantees of QoS specifications. Unless this challenge can be met, developers must resort to ad hoc solutions that may not scale or migrate well among different platforms. This thesis provides two contributions to the study of real-time Distributed Object Computing (DOC) middleware. First, it identifies potential bottlenecks and problems with respect to guaranteeing real-time performance in contemporary middleware. Experimental results illustrate how these problems lead to incorrect real-time behavior in contemporary middleware platforms. Second, this thesis presents designs and techniques for providing real-time QoS guarantees in DOC middleware in the context of TAO [6], an open-source and widely adopted implementation of real-time CORBA. Architectural solutions presented here are coupled with empirical evaluations of end-to-end real-time behavior. Analysis of the problems, forces, solutions, and consequences are presented in terms of patterns and frame-works, so that solutions obtained for TAO can be appropriately applied to other real-time systems

The coexistence between Blockchain and GDPR

The constant evolution of technology sometimes cannot avoid conflict with the parallel evolution of surrounding regulations and legislation. This dissertation highlights the Blockchain architectural design and its inherent and apparent incompatibility with the standing European directives concerning General Data Protection Regulation (GDPR) thanks to one of its most prominent features - immutability. As Blockchain-based solutions emerge and their adoption increases, the concerns about current regulation regarding storage of personal data and the conciliation with the Blockchain’s model arises. As a consequence, this research aims to find out a practical way of making Blockchains compatible with GDPR and providing a solution, with the elaboration of a Proof of Concept, along with interviews to experts of Blockchain and GDPR’s fields with the purpose of obtaining results and drawing conclusions.A constante evolução que categoriza a tecnologia não pode, por vezes, evitar conflitos com a evolução paralela de regulamentos e de legislações envolventes. Esta dissertação destaca a discrepância entre a arquitetura inerente dos sistemas de Blockchain e a sua incompatibilidade aparente e inerente às diretrizes europeias assentes sobre o Regulamento Geral de Proteção de Dados, graças a uma das suas características mais importantes – imutabilidade. À medida que as soluções baseadas em Blockchain surgem e a sua adopção aumenta, surgem preocupações sobre a regulamentação atual em relação ao armazenamento de dados pessoais e a conciliação com o modelo da Blockchain. Consequentemente, esta pesquisa tem como objectivo descobrir uma maneira prática de tornar a tecnologia Blockchain compatível com o Regulamento Geral de Proteção de Dados e fornecer uma solução através da elaboração de uma Prova de Conceito, além de entrevistas com especialistas das áreas de Blockchain e Regulamento Geral de Proteção de Dados com o objetivo de obter resultados e tirar conclusões

Real-time high-performance computing for embedded control systems

The real-time control systems industry is moving towards the consolidation of multiple computing systems into fewer and more powerful ones, aiming for a reduction in size, weight, and power. The increasing demand for higher performance in other critical domains like autonomous driving has led the industry to recently include embedded GPUs for the implementation of advanced functionalities. The highly parallel architecture of GPUs could also be leveraged in the control systems industry to develop more advanced, energy-efficient, and scalable control systems. However, the closed-source and non-deterministic nature of GPUs complicates the resource provisioning analysis required for the implementation of critical real-time systems. On the other hand, there is no indication of the integration of GPUs in the traditional development cycle of control systems, which is oriented to the use of a model-based design approach. Recently, some model-based design tools vendors have extended their development frameworks with GPU code generation capabilities targeting hybrid computing platforms, so that the model-based design environment now enables the concurrent analysis of more complex and diverse functions by simulation and automating the deployment to the final target. However, there is no indication whether these tools are well-suited for the design and development of time-sensitive systems. Motivated by these challenges, in this thesis, we contribute to the state of the art of real-time control systems towards the adoption of embedded GPUs by providing tools to facilitate the resource provisioning analysis and the integration in the model-based design development cycle. First, we present a methodology and an automated tool to extract the properties of GPU memory allocators. This tool allows the computation of the real amount of memory used by GPU applications, facilitating a correct resource provisioning analysis. Then, we present a library which allows the characterization of the use of dynamic memory in GPU applications. We use this library to characterize GPU benchmarks and we identify memory allocation patterns that could be modified to improve performance and memory consumption when targeting embedded GPUs. Based on these results, we present a tool to optimize the use of dynamic memory in legacy GPU applications executed on embedded platforms. This tool allows us to minimize the memory consumption and memory management overhead of GPU applications without rewriting them. Afterwards, we analyze the timing of control algorithms executed in embedded GPUs and we identify techniques to achieve an acceptable real-time behavior. Finally, we evaluate model-based design tools in terms of integration with GPU hardware and GPU code generation, and we propose improvements for the model-based generated GPU code. Then, we present a source-to-source transformation tool to automatically apply the proposed improvements.La industria de los sistemas de control en tiempo real avanza hacia la consolidación de múltiples sistemas informáticos en menos y más potentes sistemas, con el objetivo de reducir el tamaño, el peso y el consumo. La creciente demanda de un mayor rendimiento en otros dominios críticos, como la conducción autónoma, ha llevado a la industria a incluir recientemente GPU embebidas para la implementación de funcionalidades avanzadas. La arquitectura altamente paralela de las GPU también podría aprovecharse en la industria de los sistemas de control para desarrollar sistemas de control más avanzados, eficientes energéticamente y escalables. Sin embargo, la naturaleza privativa y no determinista de las GPUs complica el análisis de aprovisionamiento de recursos requerido para la implementación de sistemas críticos en tiempo real. Por otro lado, no hay indicios de la integración de las GPU en el ciclo de desarrollo tradicional de los sistemas de control, que está orientado al uso de un enfoque de diseño basado en modelos. Recientemente, algunos proveedores de herramientas de diseño basado en modelos han ampliado sus entornos de desarrollo con capacidades de generación de código de GPU dirigidas a plataformas informáticas híbridas, de modo que el entorno de diseño basado en modelos ahora permite el análisis simultáneo de funciones más complejas y diversas mediante la simulación y la automatización de la implementación para el objetivo final. Sin embargo, no hay indicación de si estas herramientas son adecuadas para el diseño y desarrollo de sistemas sensibles al tiempo. Motivados por estos desafíos, en esta tesis contribuimos al estado del arte de los sistemas de control en tiempo real hacia la adopción de GPUs integradas al proporcionar herramientas para facilitar el análisis de aprovisionamiento de recursos y la integración en el ciclo de desarrollo de diseño basado en modelos. Primero, presentamos una metodología y una herramienta automatizada para extraer las propiedades de los asignadores de memoria en GPUs. Esta herramienta permite el cómputo de la cantidad real de memoria utilizada por las aplicaciones GPU, facilitando un correcto análisis del aprovisionamiento de recursos. Luego, presentamos una librería que permite la caracterización del uso de memoria dinámica en aplicaciones de GPU. Usamos esta librería para caracterizar una serie de benchmarks GPU e identificamos patrones de asignación de memoria que podrían modificarse para mejorar el rendimiento y el consumo de memoria al utilizar GPUs embebidas. Con base en estos resultados, presentamos también una herramienta para optimizar el uso de la memoria dinámica en aplicaciones de GPU heredadas al ser ejecutadas en plataformas embebidas. Esta herramienta nos permite minimizar el consumo de memoria y la sobrecarga de administración de memoria de las aplicaciones GPU sin necesidad de reescribirlas. Posteriormente, analizamos el tiempo de los algoritmos de control ejecutados en GPUs embebidas e identificamos técnicas para lograr un comportamiento de tiempo real aceptable. Finalmente, evaluamos las herramientas de diseño basadas en modelos en términos de integración con hardware GPU y generación de código GPU, y proponemos mejoras para el código GPU generado por las herramientas basadas en modelos. Luego, presentamos una herramienta de transformación de código fuente para aplicar automáticamente al código generado las mejoras propuestas.Postprint (published version

A pattern-based development of secure business processes

Iga andmeturbest huvitatud äriettevõte valib iseendale sobilikud turvameetmed, et vältida ootamatuid sündmusi ja õnnetusi. Nende turvameetmete esmane ülesanne on kaitsta selle äriettevõtte ressursse ja varasid. Äriettevõtetes aset leidvad õnnetused (vähemtähtsad või katastroofilised) on enamikel juhtudel oma olemuselt sarnased ning põhjustatud sarnaste turvariskide poolt. Paljudel andmeturbe spetsialistidel on raskusi leidmaks õiget lahendust konkreetsetele probleemidele, kuna eelmiste samalaadsete probleemide lahendused ei ole korrektselt dokumenteeritud. Selles kontekstis on turvalisuse mustrid (Security Patterns) kasulikud, kuna nad esitavad tõestatud lahendusi spetsiifiliste probleemide jaoks. Käesolevas väitekirjas arendasime välja kümme turvariskidele suunatud mustrit (SRP ehk Security Risk-oriented Patterns) ja defineerisime, kuidas kasutada neid mustreid vastumeetmetena turvariskidele äriprotsesside mudelite sees. Oma olemuselt on need mustrid sõltumatud modelleerimiskeelest. Lihtsustamaks nende rakendamist, on mudelid esitatud graafilises vormingus äriprotsesside modelleerimise keeles (BPMN). Me demonstreerime turvariskidele suunatud mustrite (SRP) kasutatavust kahe tööstusettevõtte ärimudeli näite põhjal. Esitame mustrite rakendamise kohta kvantitatiivsed analüüsid ja näitame, kuidas turvariskidele suunatud mustrid (SRP) aitavad demonstreerida andmeturbe nõrku kohti ärimudelites ning pakume välja lahendusi andmeturvalisusega seotud probleemidele. Selle uurimistöö tulemused võivad julgustada andmeturvalisusega tegelevaid analüütikuid jälgima mustritel-põhinevaid lähenemisi oma äriettevõtete kaitsmiseks, et aidata seeläbi kaasa ka infosüsteemide (Information Systems (IS)) kaitsmisele.Every security concerned enterprise selects its own security measures in order to avoid unexpected events and accidents. The main objective of these security measures is to protect the enterprise’s own resources and assets from damage. Most of the time, the accidents or disasters take place in enterprise are similar in nature, and are caused by similar kind of vulnerabilities. However, many security analysts find it difficult to select the right security measure for a particular problem because the previous proven solutions are not properly documented. In this context Security Patterns could be helpful since they present the proven solutions that potentially could be reused in the similar situations. In this thesis, we develop a set of ten Security Risk-oriented Patterns (SRP) and define the way how they could be used to define security countermeasures within the business process models. In principle, patterns are modelling language-independent. Moreover, to ease their application, we represent them in a graphical form using the Business Process Modelling Notation (BPMN) modelling approach. We demonstrate the usability of the Security Risk-oriented Patterns (SRP) by applying them on two industrial business models. We present the quantitative analysis of their application. We show that Security Risk-oriented Patterns (SRP) help to determine security risks in business models and suggest rationale for security solutions. The results of this research could potentially encourage the security analysts to follow pattern-based approach to develop secure business processes, thus, contributing to secure Information Systems (IS)