Infrastructure as a service (IaaS) Cloud platforms are increasingly used in the IT industry. IaaS platforms are providers of virtual resources from a catalogue of predefined types. Improvements in virtualization technology make it possible to create and destroy virtual machines on the fly, with a low overhead. As a result, the great benefit of IaaS platforms is the ability to scale a virtual platform on the fly, while only paying for the used resources. From a research point of view, IaaS platforms raise new questions in terms of making efficient virtual platform scaling decisions and then efficiently scheduling applications on dynamic platforms. The current thesis is a step forward towards exploring and answering these questions. The first contribution of the current work is focused on resource management. We have worked on the topic of automatically scaling cloud client applications to meet changing platform usage. There have been various studies showing self-similarities in web platform traffic which implies the existence of usage patterns that may or may not be periodical. We have developed an automatic platform scaling strategy that predicted platform usage by identifying non-periodic usage patterns and extrapolating future platform usage based on them. Next we have focused on extending an existing grid platform with on-demand resources from an IaaS platform. We have developed an extension to the DIET (Distributed Interactive Engineering Toolkit) middleware, that uses a virtual market based approach to perform resource allocation. Each user is given a sum of virtual currency that he will use for running his tasks. This mechanism help in ensuring fair platform sharing between users. The third and final contribution targets application management for IaaS platforms. We have studied and developed an allocation strategy for budget-constrained workflow applications that target IaaS Cloud platforms. The workflow abstraction is very common amongst scientific applications. It is easy to find examples in any field from bioinformatics to geology. In this work we have considered a general model of workflow applications that comprise parallel tasks and permit non-deterministic transitions. We have elaborated two budget-constrained allocation strategies for this type of workflow. The problem is a bi-criteria optimization problem as we are optimizing both budget and workflow makespan. This work has been practically validated by implementing it on top of the Nimbus open source cloud platform and the DIET MADAG workflow engine. This is being tested with a cosmological simulation workflow application called RAMSES. This is a parallel MPI application that, as part of this work, has been ported for execution on dynamic virtual platforms. Both theoretical simulations and practical experiments have shown encouraging results and improvements.

Magistro baigiamajame darbe yra analizuojama įmonės perėjimo į debesų kompiuteriją nauda, aprašomi migracijos procesai ir su jais susijusios rizikos. Siekiant patvirtinti arba paneigti debesų kompiuterijos naudą, aprašomas bei pritaikomas debesų kompiuterijos atsiperkamumo modelis. Problemos analizės skyriuje pateikiami moksliniai metodai, kuriais remiantis atliekamas tyrimas, pateikiamas debesų kompiuterijos aprašymas ir supažindinama su debesų kompiuterijos rūšimis bei diegimo moduliais. Taip pat įvertinama debesų kompiuterijos rizika, analizuojamas kainų skirtumas, perėjus iš paprastos sistemos bei supažindinama su reikalavimais techninei įrangai. Be to aprašomas debesų kompiuterijos atsiperkamumo įvertinimo modelis. Teorinių bei eksperimentinių tyrimų skyriuje atskirties analizės pagalba pateikiami įmonėje vykstantys procesai prieš ir po įmonės perėjimo į debesų kompiuteriją. Apskaičiuojami kaštai būtini norint įsirengti nuosavą IT infrastruktūrą ir lyginama su debesų kompiuterijos infrastruktūros kaštais. Pritaikomas investicijų į debesų kompiuteriją atsiperkamumo įvertinimo modelis, kurio pagalba apskaičiuojami įmonės finansiniai rodikliai, tiek įprastoje IT infrastruktūroje, tiek debesų kompiuterijos infrastruktūroje. Darbo pabaigoje pateikiamos išvados, kurios rodo, jog debesų kompiuterijos rizikos yra nereikšmingos, todėl naudingumo sprendimas yra akivaizdus. / Master's thesis analyzes the company's transition to cloud computing benefits, a description of the migration processes and the associated risks. In order to confirm or refute the benefits of cloud computing, there is described and applied cloud computing valuation model for return on investment. In first section of master‘s thesis are described scientific methods by which the study is conducted, presented description of cloud computing and an introduction to cloud computing and the types of deployment modules. There is evaluated cloud computing risks, analyzed difference in prices after transition from usual IT infrastructure and introduces the requirements of the hardware. Also describes the cloud computing valuation model for return on investment. In theoretical and experimental section, with GAP analysis help are provided processes before and after the company's transition to cloud computing. Calculated the costs necessary to install its own IT infrastructure, and compared with the cloud infrastructure costs. After that, there is applied investment in cloud computing payback evaluation model that express the company's financial performance in the normal IT infrastructure and in cloud computing infrastructure. In the end are provided conclusions, which shows that the cloud risk is negligible, so the solution is obvious.

Never before in the history of humanity has so much content been created. According to Eric Schmidt, Google CEO, every two days now we create as much information as we did from the dawn of civilization up until 2003. Most of this information will either live entirely or partially on the digital realm, according to, in the next 8 years, more than one-third of all digital information created annually will either live in or pass through the cloud. A series of problems emerge when a persons needs to deal with all of this data like, photos, songs, videos, blog posts, emails, their virtual possessions. They are not limited by space and are difficult to curate; It is difficult to create the sense of value on virtual things; They lack uniqueness; and last, but not least; the main tools used to manage this data are still based on metaphors made popular by Microsoft MS-DOS in the 80’s: Files and Directories. In my degree project, I have explored possible alternatives for maintaining and bequeathing virtual possessions. The project was conducted in 24 weeks (51-22) using a Goal-Directed Design (GDD) process with strong focus on Design Ethnography, Prototyping and an extra bit of Philosophy.

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No description available.

Cloud computing is a general term for system architectures that involves delivering hosted services over the Internet, made possible by significant innovations in virtualization and distributed computing, as well as improved access to high-speed Internet. A cloud service differs from traditional hosting in three principal aspects. First, it is provided on demand, typically by the minute or the hour; second, it is elastic since the user can have as much or as little of a service as they want at any given time; and third, the service is fully managed by the provider -- user needs little more than computer and Internet access. Typically a contract is negotiated and agreed between a customer and a service provider; the service provider is required to execute service requests from a customer within negotiated quality of service (QoS) requirements for a given price. Due to dynamic nature of cloud environments, diversity of user's requests, resource virtualization, and time dependency of load, provides expected quality of service while avoiding over-provisioning is not a simple task. To this end, cloud provider must have efficient and accurate techniques for performance evaluation of cloud computing centers. The development of such techniques is the focus of this thesis. This thesis has two parts. In first part, Chapters 2, 3 and 4, monolithic performance models are developed for cloud computing performance analysis. We begin with Poisson task arrivals, generally distributed service times, and a large number of physical servers. Later on, we extend our model to include finite buffer capacity, batch task arrivals, and virtualized servers with a large number of virtual machines in each physical machine. However, a monolithic model may suffer from intractability and poor scalability due to large number of parameters. Therefore, in the second part of the thesis (Chapters 5 and 6) we develop and evaluate tractable functional performance sub-models for different servicing steps in a complex cloud center and the overall solution obtains by iteration over individual sub-model solutions. We also extend the proposed interacting analytical sub-models to capture other important aspects including pool management, power consumption, resource assigning process and virtual machine deployment of nowadays cloud centers. Finally, a performance model suitable for cloud computing centers with heterogeneous requests and resources using interacting stochastic models is proposed and evaluated.

A large number of personal cloud storage systems have emerged in recent years, such as Dropbox, iCloud, Google Drive etc. A common limitation of these system is that the users have to trust the cloud provider not to be malicious. Now we have a Unity block store, which can solve the problem and provide a secure and durable cloud-based block store. However, the base Unity system does not have the concept of file on top of its block device, thus the concurrent operations to different files can cause false sharing problem. In this thesis, we propose UnityFS, a file system built on top of the base Unity system. We design and implement the file system that maintains a mapping between files and a group of data blocks, such that the whole Unity system can support concurrent file operations to different files from multiple user devices in the personal cloud.

A large number of personal cloud storage systems have emerged in recent years, such as Dropbox, iCloud, Google Drive etc. A common limitation of these system is that the users have to trust the cloud provider not to be malicious. Now we have a Unity block store, which can solve the problem and provide a secure and durable cloud-based block store. However, the base Unity system does not have the concept of file on top of its block device, thus the concurrent operations to different files can cause false sharing problem. In this thesis, we propose UnityFS, a file system built on top of the base Unity system. We design and implement the file system that maintains a mapping between files and a group of data blocks, such that the whole Unity system can support concurrent file operations to different files from multiple user devices in the personal cloud.

The growing popularity of mobile platforms is changing the Internet user’s computing experience. Current studies suggest that the traditional ubiquitous computing landscape is shifting towards more enhanced and broader mobile computing platform consists of large number of heterogeneous devices. Smartphones and tablets begin to replace the desktop as the primary means of interacting with IT resources. While mobile devices facilitate in consuming web resources in the form of web services, the growing demand for consuming services on mobile device is introducing a complex ecosystem in the mobile environment. This research addresses the communication challenges involved in mobile distributed networks and proposes an event-driven communication approach for information dissemination. This research investigates different communication techniques such as synchronous and asynchronous polling and long-polling, server-side push as mechanisms between client-server interactions and the latest web technologies namely HTML5 standard WebSocket as communication protocol within a publish/subscribe paradigm. Finally, this research introduces and evaluates a framework that is hybrid of REST and event-based publish/subscribe for operating in the mobile environment.

Herschel and JCMT surveys of nearby star-forming regions have provided excellent images of cold dust emission across several wavelengths with unprecedented dynamic range and resolutions. Here we present spectral emissivity index and temperature maps of dust in the star-forming clumps of the Perseus molecular cloud determined from fitting SEDs to the combined Herschel and JCMT observations in the 160 μm, 250 μm, 350 μm, 500 μm, and 850 μm bands, employing the technique developed by Sadavoy et al. (2013). In NGC1333, the most complex and active star-forming clump in Perseus, we demonstrate that CO line contamination in the JCMT SCUBA-2 850 μm band is typically insignificant. The derived spectral emissivity index, β, and dust temperature, T, ranges between 0.8 - 3.0 and 7 - 50 K, respectively. Throughout Perseus, we see indications of heating from B stars and embedded protostars, and smooth β variations on the smaller scales. The distribution of β values seen in each clump differs from one clump to another, and is in general different from the diffuse ISM values (i.e., ~2), suggesting that dust grain evolution is significant in star-forming clumps. We also found coincidences between low β regions and local temperature peaks as well as locations of outflows, which may provide hints to the origins of these low β value grains, and dust grain evolution in star-forming clumps in general. / Graduate / mcychen@uvic.ca