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.

Yes / There is increasing evidence that the Cloud Computing services have become a strategic direction for governments' IT work by the dawn of the third-millennium. The inevitability of this computing technology has been recognized not only in the developed countries like the UK, USA and Japan, but also in the developing countries like the Middle East region and Malaysia, who have launched migrations towards Cloud platforms for more flexible, open, and collaborative public services. In Jordan, the cloud-based e-government project has been deemed as one of the high priority areas for the government agencies. In spite of its phenomenal evolution, various governmental cloud-based services still facing adoption challenges of e-government projects like technological, human-aspects, social, and financial which need to be treated and considered carefully by any government agency contemplating its implementation. While there have been extensive efforts to investigate the e-government adoption from the citizens' perspective using different theories and models, none have paid adequate attention to the security issues. This paper explores the different perspectives of the extent in which these challenges inhibit the acceptance and use of cloud computing in Jordanian public sector. In addition to examining the effect of these challenges on the participants’ security perception. The empirical evidence provided a total of 220 valid responses to our online questionnaire from Jordanian citizens including IT- staff from different government sectors. Based on the data analysis some significant challenges were identified. The results can help the policy makers in the public sector to guide successful acceptance and adoption of cloud-based e-government services in Jordan. / Mutah University - Jordan

Yes / Wireless capsule endoscopy (WCE) has great advantages over traditional endoscopy because it is portable and easy to use, especially in remote monitoring health-services. However, during the WCE process, the large amount of captured video data demands a significant deal of computation to analyze and retrieve informative video frames. In order to facilitate efficient WCE data collection and browsing task, we present a resource- and bandwidth-aware WCE video summarization framework that extracts the representative keyframes of the WCE video contents by removing redundant and non-informative frames. For redundancy elimination, we use Jeffrey-divergence between color histograms and inter-frame Boolean series-based correlation of color channels. To remove non-informative frames, multi-fractal texture features are extracted to assist the classification using an ensemble-based classifier. Owing to the limited WCE resources, it is impossible for the WCE system to perform computationally intensive video summarization tasks. To resolve computational challenges, mobile-cloud architecture is incorporated, which provides resizable computing capacities by adaptively offloading video summarization tasks between the client and the cloud server. The qualitative and quantitative results are encouraging and show that the proposed framework saves information transmission cost and bandwidth, as well as the valuable time of data analysts in browsing remote sensing data. / Supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013R1A1A2012904).

2023 / In the last decade, Function-as-a-Service (FaaS) became one of the popular choices for building and deploying cloud applications. Compared to Infrastructure-as-a-Service (IaaS), FaaS offers an abstraction of backend management, an easy programming model, low cold starts, and a true “pay as you go” pricing model. While efficient and relatively simpler, the cost and performance of an application, when deployed using FaaS, can be adversely affected if not properly managed and configured. Previous approaches have advocated the limited use of FaaS while scaling out the virtual machine (VM) based resources to avoid Service-Level-Objective (SLO) violations. However, these approaches miss out on potential long-term cost savings by employing FaaS consistently. Similarly, to manage a FaaS deployment, various machine learning and optimization techniques have been suggested but these techniques either have high costs or fall short as they fail to adapt to the dynamic nature of FaaS platforms. To this end, we present Thrifty, a hybrid approach to leveraging FaaS in conjunction with other cloud services to optimize both cost and performance. Thrifty consists of two main components: 1) LIBRA: a load-balancing framework to utilize IaaS and FaaS resources efficiently. Based on the demand, it decides to use either FaaS, IaaS, or both to maximize cost savings while meeting the SLOs; 2) xCOSE: a resource configuration and placement technique for FaaS deployments. It addresses the performance variability of FaaS platforms and meets the SLO by adapting the resource configurations with minimal sampling cost. It can configure single- and multi-function (service graph) applications. We evaluate Thrifty in extensive simulations and on the Amazon Web Services (AWS) cloud platform using real applications. Our evaluations show that consistent and opportunistic usage of FaaS through LIBRA can reduce SLO violations by up to 85% and cost by up to 53% when compared to other approaches to deploying cloud applications. Furthermore, xCOSE has the ability to configure simple and complex FaaS applications with minimal sampling cost.

Das Interuniversitäre Doktorandenseminar Wirtschaftsinformatik ist eine regelmäßige Veranstaltung, in deren Rahmen Doktoranden der Universitäten Chemnitz, Dresden, Freiberg, Halle, Ilmenau, Jena und Leipzig ihr Promotionsprojekt präsentieren und sich den kritischen Fragen der anwesenden Professoren und Doktoranden aller beteiligten Universitäten stellen. Auf diese Weise erhalten die Promovierenden wertvolles Feedback zu Vorgehen, Methodik und inhaltlichen Aspekten ihrer Arbeit, welches sie für ihre Promotion nutzen können. Darüber hinaus bietet das Interuniversitäre Doktorandenseminar Wirtschaftsinformatik eine Plattform für eine fachliche Auseinandersetzung mit aktuellen Themen und sich ankündigenden Trends in der Forschung der Wirtschaftsinformatik. Zudem wird ein akademischer Diskurs über die Grenzen der jeweils eigenen Schwerpunkte der Professur hinaus ermöglicht. Das nunmehr 20. Jubiläum des Doktorandenseminars fand in Chemnitz statt. Der daraus entstandene Tagungsband enthält fünf ausgewählte Beiträge zu den Themenfeldern Service Engineering, Cloud-Computing, Geschäftsprozessmanagement, Requirements Engineering, Analytics und Datenqualität und zeigt damit anschaulich die Aktualität und Relevanz, aber auch die thematische Breite der gegenwärtigen Forschung im Bereich Wirtschaftsinformatik. / The inter-university PhD seminar Business Information Systems (“Interuniversitäres Doktorandenseminar Wirtschaftsinformatik”) is an annual one-day event which is organized by the Business Information Systems chairs of the universities of Chemnitz, Dresden, Freiberg, Halle, Ilmenau, Jena and Leipzig. It serves as a platform for PhD students to present their PhD topic and the current status of the thesis. Therefore, the seminar is a good opportunity to gain further knowledge and inspiration based on the feedback and questions of the participating professors and students. The 20th Interuniversitäre Doktorandenseminar Wirtschaftsinformatik took place in Chemnitz in October 2016. The resulting proceedings include five selected articles within the following topic areas: service engineering, cloud computing, business process management, requirements engineering, analytics und data quality. They illustrate the relevance as well as the broad range of topics in current business information systems research. In case of questions and comments, please use the contact details at the end of the articles.

This diploma work is focused on the Cloud Computing and its possible applications in the Czech Republic. The first part of the work is theoretical and describes accessible sources analysis related to its topic. Historical circumstances are given in the relation to the evolution of this technology. Also few definitions are quoted, followed by the Cloud Computing basic taxonomy and common models of use. The chapter named Cloud Computing Architecture covers the generally accepted model of this technology in details. In the part focused on theory are mentioned some of the services opearating on this technology. At the end the theoretical part brings possibility of the Cloud Computing usage from the customer's and supplier's perspective. The practical part of the diploma work is divided into sections. The first one brings results of the questionnare research, performed by the author in the Czech Republic, focused on the usage of the Cloud Computing and virtualization services. In the sekond section is pre-feasibility study. The study is focused on the providing SaaS Services in the area of long-term and safe digital data store. Lastly there is an author's view on the Cloud Computing technology future and possible evolution.

Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-02-01T13:15:39Z No. of bitstreams: 1 LUIS PAULO GONCALVES PIRES.pdf: 3166033 bytes, checksum: 043d546bf3a8212c07798369bfcc2f7f (MD5) / Made available in DSpace on 2017-02-01T13:15:39Z (GMT). No. of bitstreams: 1 LUIS PAULO GONCALVES PIRES.pdf: 3166033 bytes, checksum: 043d546bf3a8212c07798369bfcc2f7f (MD5) Previous issue date: 2016-12-15 / Pontif?cia Universidade Cat?lica de Campinas ? PUC Campinas / While there is considerable enthusiasm for the migration of on-premise data centers to cloud computing services, there is still some concern about the availability of these same services. This is due, for example, to historical incidents such as that in 2011, when a crash on Amazon's servers caused sites of several of its customers to go down for almost 36 hours. In view of this, it becomes necessary to develop strategies to guarantee the availability offered by the providers. In the present work, a solution is proposed, which implements high availability in Multi-Cloud environments, through the distribution of DNS access and the use of reverse proxy. A financial analysis was also carried out, taking into account market values in Cloud Computing services, which showed that the proposed solution may even be advantageous with respect to the traditional one. Specifically, a Multi-Cloud system, consisting of two Clouds with 99.90% availability each, provides total availability of 99.999%, and it costs 34% less than a single Cloud with 99.95% availability. The simulation results, obtained in a virtualized environment, using two Clouds, with availability of 99.49% and 99.43%, showed a system availability of 99.9971%. In this way, using Multi-Cloud systems it is possible to obtain high availability systems, from lower availability Clouds, according to user?s needs, besides saving with provider services costs. / A despeito de haver consider?vel entusiasmo quanto ? migra??o de data-centers on-primese para servi?os de Cloud Computing, ainda existe certo receio no que se refere ? disponibilidade destes mesmos servi?os. Isso se deve, por exemplo, a incidentes hist?ricos como o ocorrido em 2011, quando uma falha nos servidores da Amazon fez com que sites de v?rios de seus clientes ficassem fora do ar por quase 36 horas. Em vista disso, torna-se necess?rio desenvolver estrat?gias para garantir a disponibilidade oferecida pelos provedores. No presente trabalho, descreve-se uma solu??o que implementa alta disponibilidade em ambientes Multi-Cloud, mediante a distribui??o de acesso por DNS e a utiliza??o de proxy reverso. Realizou-se tamb?m uma an?lise financeira, levando-se em conta valores de mercado em servi?os de Cloud Computing, o que mostrou que a solu??o proposta pode ser mesmo vantajosa com a rela??o ? solu??o tradicional. Especificamente, um sistema Multi-Cloud, composto por duas Clouds com disponibilidade de 99,90%, que prov? disponibilidade total de 99,999%, custa 34% menos do que uma ?nica Cloud com disponibilidade de 99,95%. Os resultados de simula??o, obtidos em ambiente virtualizado, utilizando-se duas Clouds, com disponibilidades de 99,49% e 99,43%, alcan?aram disponibilidade 99,9971%. Desta forma, utilizando-se sistemas Multi-Cloud ? poss?vel se obter sistemas de alta disponibilidade, de acordo necessidade do usu?rio, a partir de Clouds de mais baixa disponibilidade, al?m de ser poss?vel economizar com os custos dos servi?os do provedor.

L'élasticité est une propriété qui permet aux systèmes Cloud de s'auto-adapter à leur charge de travail en provisionnant et en libérant des ressources informatiques, de manière autonomique, lorsque la demande augmente et diminue. En raison de la nature imprévisible de la charge de travail et des nombreux facteurs déterminant l'élasticité, fournir des plans d'action précis pour gérer l'élasticité d'un système cloud, tout en respectant des politiques de haut niveau (performances, cout, etc.) est une tâche particulièrement difficile.Les travaux de cette thèse visent à proposer, en utilisant le formalisme des bigraphes comme modèle formel, une spécification et une implémentation des systèmes Cloud Computing élastiques sur deux aspects : structurel et comportemental.Du point de vue structurel, le but est de définir et de modéliser une structure correcte des systèmes Cloud du côté " backend ". Cette partie est supportée par les capacités de spécification fournies par le formalisme des Bigraphes, à savoir : le principe de "sorting" et de règles de construction permettant de définir les desiderata du concepteur. Concernant l'aspect comportemental, il s'agit de modéliser, valider et implémenter des stratégies génériques de mise à l'échelle automatique en vue de décrire les différents mécanismes d'auto-adaptation élastiques des systèmes cloud (mise à l'échelle horizontale, verticale, migration, etc.), en multi-couches (i.e., aux niveaux service et infrastructure). Ces tâches sont prises en charge par les aspects dynamiques propres aux Systèmes Réactifs Bigraphiques (BRS) notamment par le biais des règles de réaction.Les stratégies d'élasticité introduites visent à guider le déclenchement conditionnel des différentes règles de réaction définies, afin de décrire les comportements d'auto-adaptation des systèmes Cloud au niveau service et infrastructure. L'encodage de ces spécifications et leurs implémentations sont définis en logique de réécriture via le langage Maude. Leur bon fonctionnement est vérifié formellement à travers une technique de model-checking supportée par la logique temporelle linéaire LTL.Afin de valider ces contributions d'un point de vue quantitatif, nous proposons une approche à base de file d'attente pour analyser, évaluer et discuter les stratégies d'élasticité d'un système Cloud à travers différents scénarios simulés. Dans nos travaux, nous explorons la définition d'une "bonne" stratégie en prenant en compte une étude de cas qui repose sur la nature changeante de la charge de travail. Nous proposons une manière originale de composer plusieurs stratégies d'élasticité à plusieurs niveaux afin de garantir différentes politiques de haut-niveau. / Elasticity property allows Cloud systems to adapt to their incoming workload by provisioning and de-provisioning computing resources in an autonomic manner, as the demand rises and drops. Due to the unpredictable nature of the workload and the numerous factors that impact elasticity, providing accurate action plans to insure a Cloud system's elasticity while preserving high level policies (performance, costs, etc.) is a particularly challenging task. This thesis aims at providing a thorough specification and implementation of Cloud systems, by relying on bigraphs as a formal model, over two aspects: structural and behavioral.Structurally, the goal is to define a correct modeling of Cloud systems' "back-end" structure. This part is supported by the specification capabilities of Bigraph formalism. Specifically, via "sorting" mechanisms and construction rules that allow defining the designer's desiderata. As for the behavioral part, it consists of model, implement and validate generic elasticity strategies in order to describe Cloud systems' auto-adaptive behaviors (i.e., horizontal and vertical scaling, migration, etc.) in a cross-layer manner (i.e., at service and infrastructure levels). These tasks are supported by the dynamic aspects of Bigraphical Reactive Systems (BRS) formalism (through reaction rules).The introduced elasticity strategies aim at guiding the conditional triggering of the defined reaction rules, to describe Cloud systems' auto-scaling behaviors in a cross-layered manner. The encoding of these specifications and their implementation are defined in Rewrite Logic via Maude language. Their correctness is formally verified through a model-checking technique supported by the linear temporal logic LTL.In order to quantitatively validate these contributions, we propose a queuing-based approach in order to evaluate, analyze and discuss elasticity strategies in Cloud systems through different simulated execution scenarios. In this work, we explore the definition of a “good” strategy through a case study which considers the changing nature of the input workload. We propose an original way de compose different cross-layer elasticity strategies to guarantee different high-level policies.

The thesis introduces a study about the vulnerabilities that a company as Scania IT faces towards vendor lock-in in the transition to a cloud computing platform. Cloud computing is a term that refers to anetwork of remote servers hosted on the internet to store, manage and process data, rather than on a local server or a personal computer. Vendor lock-in is an outcome that causes companies to pay a significant cost to move between cloud providers. The effects that cause vendor lock-in that will be described are portability, interoperability and federation are called the lock-in effects. The goal of the research is to help Scania IT understand the vendor lock-in and the vulnerabilities they can face in the transition to the cloud as well as to clarify the concern that they may have against falling in vendor lock-in. The main purpose of the research is to present the various lock-in effects that are related to the transition from one cloud provider to another and the vulnerabilities that cause companies to fall in vendor lock-in. The thesis presents the reasons that motivates why Scania IT would consider using the cloud and the concerns that they may have against usage of a cloud computing platform. The results will be based on a case study of a similar company that has moved to a cloud provider and specifically Microsoft Azure and an interview of Microsoft Azure point of view with the risk of vendor lock-in. Finally, a process of interviews with different people from Scania IT to extract the current bottleneck in the development process that caused the company to think of a cloud computing platform. The results show that companies should consider many risks and factors while moving to the cloud, as vendor lock-in, cloud maturity index and their IT strategies. As a result, the thesis gives recommendations of the steps needed to minimize the risks of the cloud while maintaining the positivity of the cloud. / Uppsatsen presenterar en studie om de sårbarheter som ett företag som Scania IT har mot inlåsning i övergången till molntjänster. Molntjänster är en term som hänvisar till ett nätverk av servrar som finns på internet för att lagra, hantera och processa data, istället för på en lokal server eller en persondator. Inlåsning är ett resultat i vilket orsakar att företagen behöver betala en betydande kostnad för att flytta mellan molnleverantörer. De effekter som orsakar inlåsning vilket kommer att beskrivas är portabilitet, interoperabilitet och federation, dessa kallas inlåsningseffekter. Målet med forskningen är att hjälpa Scania IT att förstå inlåsning och sårbarheter som de kan möta i övergången till molnet. Dessutom är målet att klarlägga riskerna som de kan ha mot att falla i inlåsning. Det huvudsakliga syftet med forskningen är att presentera de olika inlåsningseffekter som är relaterade till övergången från en molnleverantör till en annan samt de sårbarheter som orsakar företagen att falla i inlåsning. Uppsatsen presenterar skäl som motiverar varför Scania IT ska överväga att använda molnet samt den oro som de kan ha mot användning av en molnleverantör. Resultaten kommer att baseras på en fallstudie av ett liknande företag som har flyttat till en molnleverantör och specifikt Microsoft Azure samt en intervju av Microsoft Azure synvinkel med risken för inlåsning. Slutligen, en rad av intervjuer med olika personer från Scania IT för att extrahera den nuvarande flaskhalsen i utvecklingsprocessen som orsakade företaget att tänka på molntjänster. Resultaten visar att företagen bör överväga många risker och faktorer när de flyttar till molnet, som exempelvis inlåsning, cloud maturity index och deras IT-strategier. Som ett resultat ger examensarbetet nödvändiga rekommendationer för att minimera riskerna för molnet samtidigt som positivitet av molnet.

<p>Cloud computing is a new buzzword within the IT-industry, and introduces a whole new way of working with IT. The technique delivers web based services, which results in that the user no longer needs to install an application locally on a computer. Since the application no longer needs to run on a local entity, but in a datacenter located on a service provider, the users no longer need any specific hardware more than a computer with an internet connection. Cloud computing also offers IT-infrastructure and development environments as services, these three service types is better known as cloud services. Through the usage of different types of cloud services, the need for maintenance and hardware is significantly reduced. Therefore, the need for IT-competence in a company is reduced, which offers the company to focus on their core business strategy. A problem with cloud computing is that because it is such a new phenomenon, there is no established definition. This makes the subject hard to understand and easily misunderstood.</p><p>Cloud computing surely seems to solve many of the problems with reliability of systems and hardware that companies struggle with on a daily basis, but is it really that simple? The purpose of this thesis is to understand which types of company preconditions that affect the integration of cloud services in a company. We will also clarify the concept of Cloud computing by divide and describe its different components.</p><p>To investigate the different types of company preconditions and there approach to cloud services we have performed interviews at different companies in associations with our case study.</p><p>The result shows that a cloud service only can be integrated to an organization as long as the organization possesses the right preconditions. We think that cloud services can bring great advantages to organizations that meet these preconditions and that cloud services has the potential to ease the way of work for organizations in the future.</p> / <p>Cloud computing är ett nytt trendord inom IT-branschen och innebär ett nytt sätt att arbeta med IT. Tekniken bygger på att användare av en applikation inte behöver installera en applikation på sin lokala dator utan applikationen förmedlas som en tjänst genom Internet. Då applikationen inte körs på någon lokal enhet utan i en datorhall hos tjänsteleverantören behöver inte användaren ha någon mer specifik hårdvara utöver en dator och en Internetanslutning för att ta del av tjänsten. Även IT-infrastruktur och utvecklingsmiljö som tjänst erbjuds på samma sätt inom Cloud computing, dessa tre typer av tjänster kallas för molntjänster. Genom att använda olika typer av molntjänster minskar den interna driften av system, underhåll av hårdvara och således behövs minmal IT-kompetens inom företag, detta tillåter företag att fokusera på sin kärnverksamhet. Då Cloud computing är ett nytt fenomen finns det ingen erkänd definition av begreppet ännu, detta resulterar i att ämnet blir svårförstått och misstolkas lätt.</p><p>Cloud computing verkar onekligen lösa problematiken med driftsäkerhet som företag tvingas att handskas med dagligen, men är de verkligen så enkelt? Syftet med uppsatsen är att redogöra för vilka förutsättningar som företag besitter som påverkar hur bra olika typer av molntjänster kan integreras i företagets verksamhet. Uppsatsen ska även redogöra för begreppet Cloud computing genom att dela upp och beskriva de olika delar som begreppet består utav.</p><p>För att utreda detta har vi bedrivit en fallstudie genom intervjuer hos utvalda företag för att undersöka företagens förutsättningar och förhållningssätt gentemot olika typer av molntjänster.</p><p>Resultatet visar att de rätta förutsättningarna krävs för att ett företag ska kunna integrera molntjänster i sin verksamhet. Vi anser att molntjänster kan medföra stora fördelar för de företagen som besitter dessa förutsättningar, och att molntjänster har potential att underlätta verksamheten för många organisationer i framtiden.</p>