758 resultados para cloud computing.


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It has been shown that cloud computing brings cost benefits and promotes efficiency in the operations of the organizations, no matter what their type or size. However, few public organizations are benefiting from this new paradigm shift in the way the organizations consume and manage computational resources. The objective of this thesis is to analyze both internal and external factors that may influence the adoption of cloud computing by public organizations and propose possible strategies that can assist these organizations in their path to cloud usage. In order to achieve this objective, a SWOT analysis has been conducted, detecting internal factors (strengths and weaknesses) and external factors (opportunities and threats) that can influence the adoption of a governmental cloud. With the application of a TOWS matrix, by combining the internal and external factors, a list of possible strategies have been formulated to be used as a guide to decision-making related to the transition to a cloud environment.

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The development of applications as well as the services for mobile systems faces a varied range of devices with very heterogeneous capabilities whose response times are difficult to predict. The research described in this work aims to respond to this issue by developing a computational model that formalizes the problem and that defines adjusting computing methods. The described proposal combines imprecise computing strategies with cloud computing paradigms in order to provide flexible implementation frameworks for embedded or mobile devices. As a result, the imprecise computation scheduling method on the workload of the embedded system is the solution to move computing to the cloud according to the priority and response time of the tasks to be executed and hereby be able to meet productivity and quality of desired services. A technique to estimate network delays and to schedule more accurately tasks is illustrated in this paper. An application example in which this technique is experimented in running contexts with heterogeneous work loading for checking the validity of the proposed model is described.

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Dissertação apresentada ao Instituto Politécnico de Castelo Branco para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Desenvolvimento de Software e Sistemas Interactivos, realizada sob a orientação científica do Doutor Osvaldo Arede dos Santos, Professor Adjunto da Unidade Técnico Científica de Informática da Escola Superior de Tecnologia do Instituto Politécnico de Castelo Branco.

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This thesis presents the formal definition of a novel Mobile Cloud Computing (MCC) extension of the Networked Autonomic Machine (NAM) framework, a general-purpose conceptual tool which describes large-scale distributed autonomic systems. The introduction of autonomic policies in the MCC paradigm has proved to be an effective technique to increase the robustness and flexibility of MCC systems. In particular, autonomic policies based on continuous resource and connectivity monitoring help automate context-aware decisions for computation offloading. We have also provided NAM with a formalization in terms of a transformational operational semantics in order to fill the gap between its existing Java implementation NAM4J and its conceptual definition. Moreover, we have extended NAM4J by adding several components with the purpose of managing large scale autonomic distributed environments. In particular, the middleware allows for the implementation of peer-to-peer (P2P) networks of NAM nodes. Moreover, NAM mobility actions have been implemented to enable the migration of code, execution state and data. Within NAM4J, we have designed and developed a component, denoted as context bus, which is particularly useful in collaborative applications in that, if replicated on each peer, it instantiates a virtual shared channel allowing nodes to notify and get notified about context events. Regarding the autonomic policies management, we have provided NAM4J with a rule engine, whose purpose is to allow a system to autonomously determine when offloading is convenient. We have also provided NAM4J with trust and reputation management mechanisms to make the middleware suitable for applications in which such aspects are of great interest. To this purpose, we have designed and implemented a distributed framework, denoted as DARTSense, where no central server is required, as reputation values are stored and updated by participants in a subjective fashion. We have also investigated the literature regarding MCC systems. The analysis pointed out that all MCC models focus on mobile devices, and consider the Cloud as a system with unlimited resources. To contribute in filling this gap, we defined a modeling and simulation framework for the design and analysis of MCC systems, encompassing both their sides. We have also implemented a modular and reusable simulator of the model. We have applied the NAM principles to two different application scenarios. First, we have defined a hybrid P2P/cloud approach where components and protocols are autonomically configured according to specific target goals, such as cost-effectiveness, reliability and availability. Merging P2P and cloud paradigms brings together the advantages of both: high availability, provided by the Cloud presence, and low cost, by exploiting inexpensive peers resources. As an example, we have shown how the proposed approach can be used to design NAM-based collaborative storage systems based on an autonomic policy to decide how to distribute data chunks among peers and Cloud, according to cost minimization and data availability goals. As a second application, we have defined an autonomic architecture for decentralized urban participatory sensing (UPS) which bridges sensor networks and mobile systems to improve effectiveness and efficiency. The developed application allows users to retrieve and publish different types of sensed information by using the features provided by NAM4J's context bus. Trust and reputation is managed through the application of DARTSense mechanisms. Also, the application includes an autonomic policy that detects areas characterized by few contributors, and tries to recruit new providers by migrating code necessary to sensing, through NAM mobility actions.

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Евгений Николов, Димитрина Полимирова - Докладът представя текущото състояние на “облачните изчисления” и “облачните информационни атаки” в светлината на компютърната вирусология и информационната сигурност. Обсъдени са категориите “облачни възможни информационни атаки” и “облачни успешни информационни атаки”. Коментирана е архитектурата на “облачните изчисления” и основните компоненти, които изграждат тяхната инфраструктура, съответно “клиенти” (“clients”), „центрове за съхранение на данни“ (“datacenters”) и „разпределени сървъри“ (“dirstributed servers”). Коментирани са и услугите, които се предлагат от “облачните изчисления” – SaaS, HaaS и PaaS. Посочени са предимствата и недостатъците на компонентите и услугите по отношение на “облачните информационни атаки”. Направен е анализ на текущото състояние на “облачните информационни атаки” на територията на България, Балканския полуостров и Югоизточна Европа по отношение на компонентите и на услугите. Резултатите са представени под формата на 3D графични обекти. На края са направени съответните изводи и препоръки под формата на заключение.

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Report published in the Proceedings of the National Conference on "Education and Research in the Information Society", Plovdiv, May, 2015

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Specification of the non-functional requirements of applications and determining the required resources for their execution are activities that demand a great deal of technical knowledge, frequently resulting in an inefficient use of resources. Cloud computing is an alternative for provisioning of resources, which can be done using either the provider's own infrastructure or the infrastructure of one or more public clouds, or even a combination of both. It enables more flexibly/elastic use of resources, but does not solve the specification problem. In this paper we present an approach that uses models at runtime to facilitate the specification of non-functional requirements and resources, aiming to facilitate dynamic support for application execution in cloud computing environments with shared resources. © 2013 IEEE.

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Napjaink informatikai világának talán legkeresettebb hívó szava a cloud computing, vagy magyar fordításban, a számítási felhő. A fordítás forrása az EU-s (Digitális Menetrend magyar változata, 2010) A számítási felhő üzleti modelljének részletes leírását adja (Bőgel, 2009). Bőgel György ismerteti az új, közműszerű informatikai szolgáltatás kialakulását és gazdasági előnyeit, nagy jövőt jósolva a számítási felhőnek az üzleti modellek versenyében. A szerző – a számítási felhő üzleti előnyei mellett – nagyobb hangsúlyt fektet dolgozatában a gyors elterjedést gátló tényezőkre, és arra, hogy mit jelentenek az előnyök és a hátrányok egy üzleti, informatikai vagy megfelelőségi vezető számára. Nem csökkentve a cloud modell gazdasági jelentőségét, fontosnak tartja, hogy a problémákról és a kockázatokról is szóljon. Kiemeli, hogy a kockázatokban – különösen a biztonsági és adatvédelmi kockázatokban – lényeges különbségek vannak az Európai Gazdasági Térség és a világ többi része, pl. az Amerikai Egyesült Államok között. A cikkben rámutat ezekre a különbségekre, és az olvasó magyarázatot kap arra is, hogy miért várható a számítási felhő lassabb terjedése Európában, mint a világ más részein. Bemutatja az EU erőfeszítéseit is a számítási felhő európai terjedésének elősegítésére, tekintettel a modell versenyképességet növelő hatására. / === / One of the most popular concept of the recent web searches is cloud computing. Several authors present detailed description of the new service model and it's business benefits and cite the optimistic prognoses of the cloud experts regarding the competition of information system service models. The author analyses the operational benefits of the cloud application and give a detailed description of the inhibitors of the fast expansion of the service modell. He also analyses the pros and cons of the cloud for a business manager, an information and a compliance officer. When understanding the advantages of the cloud, it is equally important to review the problems and risks associated with the model. The paper gives a list of the expected cloud-specific risks. It also explains the differences in security and data protection approach between the European Economic Area and the rest of the world, including the USA. The explains why slower expansion of the cloud modell is expected in Europe than in the rest of the world. The efforts of the EU Committee in helping to spread the cloud model is also presented, as the EU's officers consider the model as an important element of competitiveness.

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Néhány éve vonult be a köztudatba a cloud computing fogalom, mely ma már a szakirodalomban és az informatikai alkalmazásokban is egyre nagyobb teret foglal el. Ez az új IT-technológia a számítási felhő számítástechnikai szolgáltatásaihoz kapcsolódó ERP-rendszerek szabványosítását, elterjedését eredményezi. A szerzők cikkükben áttekintést adnak a cloud computing mai helyzetéről és a számítási felhőben működő adatfeldolgozó rendszerekkel (kiemelten ERP) kapcsolatos felhasználói elvárásokról, illetve kezdeti, németországi alkalmazási tapasztalatokról. Külön tárgyalják az ERP-rendszerek új kiválasztási céljait és kritériumait, melyek a felhőkörnyezet speciális lehetőségei miatt alakultak ki. _____ The concept of ‘Cloud’ as an IT notion emerged in the past years and proliferated within the business and IT professional community. The concept of cloud gained awareness both in the professional and scientific literature and in the practice of IT/IS world. The cloud has a profound impact on the Business Information Systems, especially on ERP systems. Indirectly, the cloud leads to a massive standardization on ERP systems and their services. In this paper, the authors provide a literature overview about the current situation of Cloud Computing and the requirements established by end-users against the other data processing facilities and systems, outstandingly the ERP systems. The majority of investigated cases are based on samples from Germany. Furthermore, the initial experiences of application are discussed. Separately, the recent selection objectives and criteria for ERP systems are investigated that came into existence because the appearance of Cloud in the IT environment.

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Cloud computing realizes the long-held dream of converting computing capability into a type of utility. It has the potential to fundamentally change the landscape of the IT industry and our way of life. However, as cloud computing expanding substantially in both scale and scope, ensuring its sustainable growth is a critical problem. Service providers have long been suffering from high operational costs. Especially the costs associated with the skyrocketing power consumption of large data centers. In the meantime, while efficient power/energy utilization is indispensable for the sustainable growth of cloud computing, service providers must also satisfy a user's quality of service (QoS) requirements. This problem becomes even more challenging considering the increasingly stringent power/energy and QoS constraints, as well as other factors such as the highly dynamic, heterogeneous, and distributed nature of the computing infrastructures, etc. ^ In this dissertation, we study the problem of delay-sensitive cloud service scheduling for the sustainable development of cloud computing. We first focus our research on the development of scheduling methods for delay-sensitive cloud services on a single server with the goal of maximizing a service provider's profit. We then extend our study to scheduling cloud services in distributed environments. In particular, we develop a queue-based model and derive efficient request dispatching and processing decisions in a multi-electricity-market environment to improve the profits for service providers. We next study a problem of multi-tier service scheduling. By carefully assigning sub deadlines to the service tiers, our approach can significantly improve resource usage efficiencies with statistically guaranteed QoS. Finally, we study the power conscious resource provision problem for service requests with different QoS requirements. By properly sharing computing resources among different requests, our method statistically guarantees all QoS requirements with a minimized number of powered-on servers and thus the power consumptions. The significance of our research is that it is one part of the integrated effort from both industry and academia to ensure the sustainable growth of cloud computing as it continues to evolve and change our society profoundly.^

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Cloud computing realizes the long-held dream of converting computing capability into a type of utility. It has the potential to fundamentally change the landscape of the IT industry and our way of life. However, as cloud computing expanding substantially in both scale and scope, ensuring its sustainable growth is a critical problem. Service providers have long been suffering from high operational costs. Especially the costs associated with the skyrocketing power consumption of large data centers. In the meantime, while efficient power/energy utilization is indispensable for the sustainable growth of cloud computing, service providers must also satisfy a user's quality of service (QoS) requirements. This problem becomes even more challenging considering the increasingly stringent power/energy and QoS constraints, as well as other factors such as the highly dynamic, heterogeneous, and distributed nature of the computing infrastructures, etc. In this dissertation, we study the problem of delay-sensitive cloud service scheduling for the sustainable development of cloud computing. We first focus our research on the development of scheduling methods for delay-sensitive cloud services on a single server with the goal of maximizing a service provider's profit. We then extend our study to scheduling cloud services in distributed environments. In particular, we develop a queue-based model and derive efficient request dispatching and processing decisions in a multi-electricity-market environment to improve the profits for service providers. We next study a problem of multi-tier service scheduling. By carefully assigning sub deadlines to the service tiers, our approach can significantly improve resource usage efficiencies with statistically guaranteed QoS. Finally, we study the power conscious resource provision problem for service requests with different QoS requirements. By properly sharing computing resources among different requests, our method statistically guarantees all QoS requirements with a minimized number of powered-on servers and thus the power consumptions. The significance of our research is that it is one part of the integrated effort from both industry and academia to ensure the sustainable growth of cloud computing as it continues to evolve and change our society profoundly.

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Individuals and corporate users are persistently considering cloud adoption due to its significant benefits compared to traditional computing environments. The data and applications in the cloud are stored in an environment that is separated, managed and maintained externally to the organisation. Therefore, it is essential for cloud providers to demonstrate and implement adequate security practices to protect the data and processes put under their stewardship. Security transparency in the cloud is likely to become the core theme that underpins the systematic disclosure of security designs and practices that enhance customer confidence in using cloud service and deployment models. In this paper, we present a framework that enables a detailed analysis of security transparency for cloud based systems. In particular, we consider security transparency from three different levels of abstraction, i.e., conceptual, organisation and technical levels, and identify the relevant concepts within these levels. This allows us to provide an elaboration of the essential concepts at the core of transparency and analyse the means for implementing them from a technical perspective. Finally, an example from a real world migration context is given to provide a solid discussion on the applicability of the proposed framework.

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Aim of the study: To introduce and describe FlorNExT®, a free cloud computing application to estimate growth and yield of maritime pine (Pinus pinaster Ait.) even-aged stands in the Northeast of Portugal (NE Portugal). Area of study: NE Portugal. Material and methods: FlorNExT® implements a dynamic growth and yield modelling framework which integrates transition functions for dominant height (site index curves) and basal area, as well as output functions for tree and stand volume, biomass, and carbon content. Main results: FlorNExT® is freely available from any device with an Internet connection at: http://flornext.esa.ipb.pt/. Research highlights: This application has been designed to make it possible for any stakeholder to easily estimate standing volume, biomass, and carbon content in maritime pine stands from stand data, as well as to estimate growth and yield based on four stand variables: age, density, dominant height, and basal area. FlorNExT® allows planning thinning treatments. FlorNExT® is a fundamental tool to support forest mobilization at local and regional scales in NE Portugal. Material and methods: FlorNExT® implements a dynamic growth and yield modelling framework which integrates transition functions for dominant height (site index curves) and basal area, as well as output functions for tree and stand volume, biomass, and carbon content. Main results: FlorNExT® is freely available from any device with an Internet connection at: http://flornext.esa.ipb.pt/. Research highlights: This application has been designed to make it possible for any stakeholder to easily estimate standing volume, biomass, and carbon content in maritime pine stands from stand data, as well as to estimate growth and yield based on four stand variables: age, density, dominant height, and basal area. FlorNExT® allows planning thinning treatments. FlorNExT® is a fundamental tool to support forest mobilization at local and regional scales in NE Portugal.