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Optimising Fault Tolerance in Real-time Cloud Computing IaaS EnvironmentMohammed, Bashir, Kiran, Mariam, Awan, Irfan U., Maiyama, Kabiru M. 22 August 2016 (has links)
Yes / Fault tolerance is the ability of a system to respond
swiftly to an unexpected failure. Failures in a cloud computing
environment are normal rather than exceptional, but fault
detection and system recovery in a real time cloud system is a
crucial issue. To deal with this problem and to minimize the risk
of failure, an optimal fault tolerance mechanism was introduced
where fault tolerance was achieved using the combination of the
Cloud Master, Compute nodes, Cloud load balancer, Selection
mechanism and Cloud Fault handler. In this paper, we proposed
an optimized fault tolerance approach where a model is designed
to tolerate faults based on the reliability of each compute node
(virtual machine) and can be replaced if the performance is not
optimal. Preliminary test of our algorithm indicates that the rate
of increase in pass rate exceeds the decrease in failure rate and it
also considers forward and backward recovery using diverse
software tools. Our results obtained are demonstrated through
experimental validation thereby laying a foundation for a fully
fault tolerant IaaS Cloud environment, which suggests a good
performance of our model compared to current existing
approaches. / Petroleum Technology Development Fund (PTDF)
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Fail Over Strategy for Fault Tolerance in Cloud Computing EnvironmentMohammed, Bashir, Kiran, Mariam, Maiyama, Kabiru M., Kamala, Mumtaz A., Awan, Irfan U. 04 April 2017 (has links)
Yes / Cloud fault tolerance is an important issue in cloud computing platforms and applications. In the event of an unexpected
system failure or malfunction, a robust fault-tolerant design may allow the cloud to continue functioning correctly
possibly at a reduced level instead of failing completely. To ensure high availability of critical cloud services, the
application execution and hardware performance, various fault tolerant techniques exist for building self-autonomous
cloud systems. In comparison to current approaches, this paper proposes a more robust and reliable architecture using
optimal checkpointing strategy to ensure high system availability and reduced system task service finish time. Using
pass rates and virtualised mechanisms, the proposed Smart Failover Strategy (SFS) scheme uses components such as
Cloud fault manager, Cloud controller, Cloud load balancer and a selection mechanism, providing fault tolerance via
redundancy, optimized selection and checkpointing. In our approach, the Cloud fault manager repairs faults generated
before the task time deadline is reached, blocking unrecoverable faulty nodes as well as their virtual nodes. This scheme
is also able to remove temporary software faults from recoverable faulty nodes, thereby making them available for future
request. We argue that the proposed SFS algorithm makes the system highly fault tolerant by considering forward and
backward recovery using diverse software tools. Compared to existing approaches, preliminary experiment of the SFS
algorithm indicate an increase in pass rates and a consequent decrease in failure rates, showing an overall good
performance in task allocations. We present these results using experimental validation tools with comparison to other
techniques, laying a foundation for a fully fault tolerant IaaS Cloud environment.
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Emulátor byte kódu jazyka Java vhodný pro detekci a analýzu malware / Java Byte Code Emulator Suitable for Malware Detection and AnalysisKubernát, Tomáš January 2013 (has links)
The goal of this thesis is to create a virtual machine that emulates a running programs written in Java programing language, which would be suitable for malware analysis and detection. The emulator is able to detect arguments of exploitable methods from Java standard classes, the order of calling these exploitable methods and also execution the test application. Overall functionality was tested on appropriate examples in which held its own measurements. At the end of the paper we describe testing of the emulator, which also contains tables and graphs for better results visualization.
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Verifikace metadat zvukových záznamů / Vefication of Metadata for Sound RecordingsPřerovský, Petr January 2012 (has links)
The work deals with verification of the metadata of audio recordings in an environment of mobile phones running Android. The text work is divided into three main parts. The first part is focused more on theoretical basis, where the main emphasis on the description of Android, application structure, description of the audio MP3 file and theoretical basis of Fourier transform in signal processing. The second part is devoted to solution design, analysis and implementation. The third part deals with testing.
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App enabling environment to Volvo CE platformsDuff, Gerard January 2014 (has links)
This thesis was submitted to the faculty of Innovation, Design and Technology, IDT, at Mälardalen university in Västerås, Sweden as a partial fulfillment of the requirements to obtain the M.Sc. in computer science, specializing in embedded systems. The work presented was carried out in the months January to June in 2014 partially in Volvo Construction Equipment, Volvo CE, Eskilstuna, and partially at Mälardalen university in Västerås. Federated Resilient Embedded Systems Technology for AUTOSAR, FRESTA, is a collaborative project between Volvo and the Swedish Institute of Computer Science, SICS, that aims to make it possible to add third party applications to vehicle’s computer systems without compromising system security and robustness. The mechanism is developed by SICS for AUTOSAR, AUTomotive Open System ARchitecture, an open standardized automotive software architecture for vehicles. The following report documents the efforts to study and port the FRESTA mechanism to the Volvo CE platform, and develop a Java application to test the porting. The investigation will aspire to determine if it is feasible to introduce Java based third party applications to resource constrained embedded systems, without causing a deterioration in the predictability and security of the system. / Avhandlingen lades fram för fakulteten för innovation, design och teknik, IDT, vid Mälardalens högskola i Västerås som en del av kraven för att erhålla M.Sc. i datavetenskap med inriktning mot inbyggda system. Arbetet genomfördes under månaderna januari till juni 2014 delvis i Volvo Construction Equipment, Volvo CE, Eskilstuna, och delvis vid Mälardalens högskola i Västerås. Federated Resilient Embedded Systems Technology for AUTOSAR, FRESTA, är ett samarbetsprojekt mellan Volvo och Svenska Institutet för datavetenskap, SICS, som syftar till att göra det möjligt att lägga tredjepartsapplikationer till fordonets datorsystem utan att äventyra systemets säkerhet och robusthet. Mekanismen är utvecklat av SICS för AUTOSAR, Automotive Open System Architecture, en öppen standardiserad fordons programvaruarkitektur för fordon. Följande rapport dokumenterar arbetet med att studera Fresta mekanismen till Volvo CE-plattformen, och utveckla ett Java-program för att testa portning. Undersökningen kommer att sträva efter att avgöra om det är genomförbart att införa en Java-baserad tredje part för att resursbegränsa inbyggda system, utan att orsaka en försämring av förutsägbarhet och säkerhet i systemet.
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Storage-Centric System Architectures for Networked, Resource-Constrained DevicesTsiftes, Nicolas January 2016 (has links)
The emergence of the Internet of Things (IoT) has increased the demand for networked, resource-constrained devices tremendously. Many of the devices used for IoT applications are designed to be resource-constrained, as they typically must be small, inexpensive, and powered by batteries. In this dissertation, we consider a number of challenges pertaining to these constraints: system support for energy efficiency; flash-based storage systems; programming, testing, and debugging; and safe and secure application execution. The contributions of this dissertation are made through five research papers addressing these challenges. Firstly, to enhance the system support for energy-efficient storage in resource-constrained devices, we present the design, implementation, and evaluation of the Coffee file system and the Antelope DBMS. Coffee provides a sequential write throughput that is over 92% of the attainable flash driver throughput, and has a constant memory footprint for open files. Antelope is the first full-fledged relational DBMS for sensor networks, and it provides two novel indexing algorithms to enable fast and energy-efficient database queries. Secondly, we contribute a framework that extends the functionality and increases the performance of sensornet checkpointing, a debugging and testing technique. Furthermore, we evaluate how different data compression algorithms can be used to decrease the energy consumption and data dissemination time when reprogramming sensor networks. Lastly, we present Velox, a virtual machine for IoT applications. Velox can enforce application-specific resource policies. Through its policy framework and its support for high-level programming languages, Velox helps to secure IoT applications. Our experiments show that Velox monitors applications' resource usage and enforces policies with an energy overhead below 3%. The experimental systems research conducted in this dissertation has had a substantial impact both in the academic community and the open-source software community. Several of the produced software systems and components are included in Contiki, one of the premier open-source operating systems for the IoT and sensor networks, and they are being used both in research projects and commercial products.
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Hur skyddar man sig mot malware?Fawaz, Ali January 2019 (has links)
Detta är sammanställning av en lista med åtgärder till helt vanliga datoranvändare för hur dessa ska skydda sig mot skadlig kod. Fokus ligger på misstag av den mänskliga faktorn och mitigering utifrån dessa. Arbetet innehåller en litteraturstudie och ett experiment. Experimentet är uppdelat så att flera åtgärder mot skadlig kod kunde testas. Litteraturstudien redogör för fakta om de olika typerna av skadlig kod. Med hjälp av experimentet kunde ett flertal åtgärder mot skadlig kod användas i listan som sammanställdes. Experimentet visar framförallt hur viktigt det är med enkla uppdateringar av antivirusprogram och operativsystem.
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Ambientes de execução para o modelo de atores em plataformas hierárquicas de memória compartilhada com processadores de múltiplos núcleos / Dealing with actor runtime environments on hierarchical shared memory multi-core platformsFrancesquini, Emilio de Camargo 16 May 2014 (has links)
O modelo de programação baseado em atores é frequentemente utilizado para o desenvolvimento de grandes aplicações e sistemas. Podemos citar como exemplo o serviço de bate-papo do Facebook ou ainda o WhatsApp. Estes sistemas dão suporte a milhares de usuários conectados simultaneamente levando em conta estritas restrições de desempenho e interatividade. Tais sistemas normalmente são amparados por infraestruturas de hardware com processadores de múltiplos núcleos. Normalmente, máquinas deste porte são baseadas em uma estrutura de memória compartilhada hierarquicamente (NUMA - Non-Uniform Memory Access). Nossa análise dos atuais ambientes de execução para atores e a pesquisa na literatura mostram que poucos estudos sobre a adequação deste ambientes a essas plataformas hierárquicas foram conduzidos. Estes ambientes de execução normalmente assumem que o espaço de memória é uniforme o que pode causar sérios problemas de desempenho. Nesta tese nós estudamos os desafios enfrentados por um ambiente de execução para atores quando da sua execução nestas plataformas. Estudamos particularmente os problemas de gerenciamento de memória, de escalonamento e de balanceamento de carga. Neste documento nós também analisamos e caracterizamos as aplicações baseadas no modelo de atores. Tal análise nos permitiu evidenciar o fato de que a execução de benchmarks e aplicações criam estruturas de comunicação peculiares entre os atores. Tais peculiaridades podem, então, ser utilizadas pelos ambientes de execução para otimizar o seu desempenho. A avaliação dos grafos de comunicação e a implementação da prova de conceito foram feitas utilizando um ambiente de execução real, a máquina virtual da linguagem Erlang. A linguagem Erlang utiliza o modelo de atores para concorrência com uma sintaxe clara e consistente. As modificações que nós efetuamos nesta máquina virtual permitiram uma melhora significativa no desempenho de certas aplicações através de uma melhor afinidade de comunicação entre os atores. O escalonamento e o balanceamento de carga também foram melhorados graças à utilização do conhecimento sobre o comportamento da aplicação e sobre a plataforma de hardware. / The actor model is present in several mission-critical systems, such as those supporting WhatsApp and Facebook Chat. These systems serve thousands of clients simultaneously, therefore demanding substantial computing resources usually provided by multi-processor and multi-core platforms. Non-Uniform Memory Access (NUMA) architectures account for an important share of these platforms. Yet, research on the suitability of the current actor runtime environments for these machines is very limited. Current runtime environments, in general, assume a flat memory space, thus not performing as well as they could. In this thesis we study the challenges hierarchical shared memory multi-core platforms present to actor runtime environments. In particular, we investigate aspects related to memory management, scheduling, and load-balancing. In this document, we analyze and characterize actor based applications to, in light of the above, propose improvements to actor runtime environments. This analysis highlighted the existence of peculiar communication structures. We argue that the comprehension of these structures and the knowledge about the underlying hardware architecture can be used in tandem to improve application performance. As a proof of concept, we implemented our proposal using a real actor runtime environment, the Erlang Virtual Machine (VM). Concurrency in Erlang is based on the actor model and the language has a consistent syntax for actor handling. Our modifications to the Erlang VM significantly improved the performance of some applications thanks to better informed decisions on scheduling and on load-balancing.
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Konsolidace serverů za použití virtualizace / Server consolidation and virtualizationRybák, Martin January 2007 (has links)
The thesis deals with the topic of complexity of current IT. As a result, the consolidation of servers using virtualization is the answer to permanently growing complexity of server infrastructure. The thesis summarizes the basic aspects of this issue, compares the contributions and tries to analyze problems which can emerge. Further, it points a way of consolidation journey, compares different types of virtualization and elaborates the contributions of virtualization for corporate IS/ICT and its flexibility of solution. It analyzes present state of the market with virtualization tools, describes and compares some products of the market key players and analyzes the new opportunities for virtualization, e. g. the virtual desktop infrastructure. At the end, it suggests an approach for consolidated project solution in practice and tries to show some basic steps which should not be omitted. Besides the complex view to the topic, the thesis also presents the contributions, risks and questions to be raised and, at least partly, answers these questions.
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Architectural Introspection and ApplicationsLitty, Lionel 30 August 2010 (has links)
Widespread adoption of virtualization has resulted in an increased interest in Virtual Machine (VM) introspection. To perform useful analysis of the introspected VMs, hypervisors must deal with the semantic gap between the low-level information available to them and the high-level OS abstractions they need. To bridge this gap, systems have proposed making assumptions derived from the operating system source code or symbol information. As a consequence, the resulting systems create a tight coupling between the hypervisor and the operating systems run by the introspected VMs. This coupling is undesirable because any change to the internals of the operating system can render the output of the introspection system meaningless. In particular, malicious software can evade detection by making modifications to the introspected OS that break these assumptions.
Instead, in this thesis, we introduce Architectural Introspection, a new introspection approach that does not require information about the internals of the introspected VMs. Our approach restricts itself to leveraging constraints placed on the VM by the hardware and the external environment. To interact with both of these, the VM must use externally specified interfaces that are both stable and not linked with a specific version of an operating system. Therefore, systems that rely on architectural introspection are more versatile and more robust than previous approaches to VM introspection.
To illustrate the increased versatility and robustness of architectural introspection, we describe two systems, Patagonix and P2, that can be used to detect rootkits and unpatched software, respectively. We also detail Attestation Contracts, a new approach to attestation that relies on architectural introspection to improve on existing attestation approaches. We show that because these systems do not make assumptions about the operating systems used by the introspected VMs, they can be used to monitor both Windows and Linux based VMs. We emphasize that this ability to decouple the hypervisor from the introspected VMs is particularly useful in the emerging cloud computing paradigm, where the virtualization infrastructure and the VMs are managed by different entities. Finally, we show that these approaches can be implemented with low overhead, making them practical for real world deployment.
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