• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1674
  • 332
  • 250
  • 173
  • 127
  • 116
  • 53
  • 52
  • 44
  • 44
  • 25
  • 20
  • 19
  • 18
  • 11
  • Tagged with
  • 3354
  • 1656
  • 730
  • 505
  • 439
  • 422
  • 399
  • 337
  • 325
  • 320
  • 317
  • 315
  • 306
  • 265
  • 259
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Efficient Data Access in Cloudlet-based Mobile Cloud Computing

Hou, Zhijun 14 August 2018 (has links)
The growth in mobile devices and applications has leveraged the emergence of mobile cloud computing, which allows the access to services at any place and extends mobile computing. Usually, the current mobile network consists of a restricting factor in supporting such access because, from a global perspective, cloud servers are distant from most mobile users, which introduces signi cant latency and results in considerably delays on applications in mobile devices. On the other hand, Cloudlet are usually on the edge of Mobile Networks and can serve content to mobile users with high availability and high performance. This thesis reviews both the traditional mobile cloud computing and the Cloudlet architecture. A taxonomy on the Cloudlet architecture is introduced and three related technologies are discussed. Based on the user needs in this environment, personal model which is used to predict individual behaviour and group model which considers caching popular data for several users are proposed. Making use of these two models and the Cloudlet architecture, two data access schemes are designed based on model distribution and data pre-distribution. We have conducted experiments and analysis for both the models and data access schemes. For the models, model efficiency and comparisons among different technologies are analysed. Simulation results for the data access schemes show that the proposed schemes outperform the existing method from both battery consumption and performance aspects.
22

A cloud chamber study of pair production

Wolfe, Harry Bernard January 1951 (has links)
The present status of the Bethe-Heitler theory of pair production is analysed, and results are given which can be compared with experiment. The main points of interest in the pair formation process are the cross-section, energy and angular distribution of the electrons, the momentum imparted to the nucleus, and the manner in which these factors vary with photon energy and atomic number. Although the assumptions involved, such as the Born Approximation, appear to be justified, a review of the literature shows that experimental results have not always been in entire agreement with theory. For instance, the experimental distribution of Ē₊-Ē₋ follows neither the Bethe-Heitler nor the Jaeger-Hulme theory. The proposed experiment is to be carried out with a cloud chamber using Xenon as the gas, and ThC" as the γ-ray source. The errors involved in the method are discussed. To minimize scattering error a new method of analysis of cloud chamber tracks is suggested, in which the angle between successive equidistant chords is measured. The nine inch chamber is of the rubber diaphragm type. The operation of the chamber and camera has been made entirely automatic. The magnetic field is obtained by a pair of Helmholz coils. Two General Electric F.T. 126 flash lamps provide sufficient light for photography. Stereoscopic pictures are obtained by the double mirror method. A great number of difficulties had to be overcome, especially in the functioning of the expansion valves, in order to get good electron tracks and consistent operation. It has been found that it is very important to use correct procedure in filling the chamber and "cleaning" it out for the production of tracks. Very nice electron tracks have been obtained with a ThC" source and Argon in the chamber. Preliminary observations indicate that the source may need to be shuttered, and that the chamber will need a thin window. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
23

A cloud chamber study of the radiations from zinc65

Parry, Kenneth John January 1949 (has links)
The primary object of this research project has been to construct a Wilson cloud chamber for nuclear physics investigations, in particular, suitable for use with the high voltage Van de Graeff generator now being erected in the Physics Department of the University of British Columbia. The chamber design is based on drawings obtained from the Chalk River Laboratories of the National Research Council, and is basically similar to the design developed by various people through the period 1935 - 1940 at the Cavendish Laboratory, Cambridge. The control unit design is essentially the same as that developed at the Chalk River Laboratories, N. R. C., and provides for automatic operation of the chamber. The whole unit has been assembled on a movable trolley so that the chamber may be used in conjunction with the ion beam from the electrostatic generator. The whole of the machine and assembly work was carried out in the Physics Department at U. B. C., using castings obtained from a local Vancouver firm. It was intended had time permitted to check carefully the performance of the chamber by conducting a brief experiment involving the photographing of numerous electron tracks. To this end a source of Zinc⁶⁵ was obtained, which is a positron emmitter, but only a very preliminary examination of the radiations from it has so far been possible. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
24

Cloud Computing Service Discovery Framework for IaaS and PaaS Models

Firozbakht, Farzad January 2016 (has links)
Cloud service discovery is a new challenge which requires a dedicated framework in order to approach it. Over the past few years, several methods and frameworks have been developed for cloud service discovery but they are mostly designed for all cloud computing models in general which are not optimal. The three cloud computing models are Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS), each computing model has its own set of resources. Having one single discovery framework for all three is not very efficient and the implementation of such a framework is complex with lots of overhead. The existing frameworks for cloud service discovery are mostly semantic-based and there are a few syntax-based frameworks that are using the filter by Attribute method as their solution. This research proposes a cloud service discovery framework focusing on IaaS and PaaS cloud computing models. Our framework is using a syntax-based query engine at its core and uses Extensible Markup Language (XML) for storing cloud service information. We eventually test the framework from the user point of view with IaaS and PaaS cloud services from real cloud service providers. Such a framework could be a good solution for IaaS and PaaS since it is accurate enough for service discovery and easy to update.
25

Multifractal analysis of cloud radiances from 5000 km to 1 km

Stanway, John David January 2000 (has links)
No description available.
26

Zenith measurements of cloud emissivity in the 8-13 micron waveland.

Allen, John Robin January 1969 (has links)
No description available.
27

Cloud Computing and Decision-Making : Determinants, Modelling and Impacts / Cloud computing et la décision : déterminants, modélisation et impacts

Cheng, Xiaolin 20 November 2017 (has links)
Cette thèse cherche à traiter des sujets de l’adoption de cloud et la décision de cloud. Elle analyse des déterminants de l’adoption, discute des services de cloud et compare des fournisseurs de cloud. Cloud computing a des dimensions à la fois techniques et organisationnelles. Jusqu’à présent, la dimension organisationnelle a reçu peu d’attention, et cloud computing a été essentiellement considéré d’un point de vue technique. Cependant, la “cloudification” des systèmes d’information pose de nombreuses questions économiques et managériales qui doivent être évaluées. Il est donc important d’enrichir notre compréhension des phénomènes liés à la "virtualization" de l’information, à travers un examen de leurs caractéristiques multidimensionnelles. En général, cette thèse démontre que l’utilité perçue, la facilité d’utilisation perçue, la complexité et la compatibilité sont des facteurs clés de l’adoption du cloud, le savoir-faire informatique joue également un rôle important dans le processus de la décision ; la plupart des petits fournisseurs de cloud ont des performances plus stables et plus performantes que les grands fournisseurs de cloud, la performance du processeur ayant un impact significatif sur le prix. Cette thèse contribue beaucoup aux dimensions théoriques et managériales de la recherche sur cloud, mais il y a plus de travail de recherche à faire du point de vue de l’adoption de cloud et de la prise de décision dans le cloud. La recherche future se concentrera sur les limites de la recherche. / This dissertation addresses cloud computing adoption and decision-making issues. It analyzes adoption determinants, discusses cloud services, and compares cloud providers. Cloud computing has both technical and organizational dimensions. Until recently the organizational dimension has received little attention, and cloud computing has essentially been considered from a technical perspective. However, the "cloudification" of information systems poses many economic and managerial questions that need to be evaluated. It is therefore important to enrich our understanding of phenomena related to the "virtualization" of information, through an examination of their multidimensional characteristics. Overall, this dissertation finds that perceived usefulness, perceived ease of use, complexity and compatibility are key factors for cloud adoption, It know-how plays also an important role in the decision process; most small cloud providers have more stable and better computing performance than large cloud providers, the performance of CPU impact price significantly. This dissertation contributes a lot to the theoretical and managerial dimensions of cloud computing research, however, there exists more research work to do as the aforementioned research limitations from the perspective of cloud adoption and cloud decision-making. Future research will focus on the limitions of the research.
28

Scientific High Performance Computing (HPC) Applications On The Azure Cloud Platform

Agarwal, Dinesh 10 May 2013 (has links)
Cloud computing is emerging as a promising platform for compute and data intensive scientific applications. Thanks to the on-demand elastic provisioning capabilities, cloud computing has instigated curiosity among researchers from a wide range of disciplines. However, even though many vendors have rolled out their commercial cloud infrastructures, the service offerings are usually only best-effort based without any performance guarantees. Utilization of these resources will be questionable if it can not meet the performance expectations of deployed applications. Additionally, the lack of the familiar development tools hamper the productivity of eScience developers to write robust scientific high performance computing (HPC) applications. There are no standard frameworks that are currently supported by any large set of vendors offering cloud computing services. Consequently, the application portability among different cloud platforms for scientific applications is hard. Among all clouds, the emerging Azure cloud from Microsoft in particular remains a challenge for HPC program development both due to lack of its support for traditional parallel programming support such as Message Passing Interface (MPI) and map-reduce and due to its evolving application programming interfaces (APIs). We have designed newer frameworks and runtime environments to help HPC application developers by providing them with easy to use tools similar to those known from traditional parallel and distributed computing environment set- ting, such as MPI, for scientific application development on the Azure cloud platform. It is challenging to create an efficient framework for any cloud platform, including the Windows Azure platform, as they are mostly offered to users as a black-box with a set of application programming interfaces (APIs) to access various service components. The primary contributions of this Ph.D. thesis are (i) creating a generic framework for bag-of-tasks HPC applications to serve as the basic building block for application development on the Azure cloud platform, (ii) creating a set of APIs for HPC application development over the Azure cloud platform, which is similar to message passing interface (MPI) from traditional parallel and distributed setting, and (iii) implementing Crayons using the proposed APIs as the first end-to-end parallel scientific application to parallelize the fundamental GIS operations.
29

Cloud computing in the 3PL industry. A profound insight into the benefits & challenges of cloud-based services: A two fold approach

Gantzia, Danai, Sklatinioti, Maria Eleni January 2014 (has links)
Problem: Practical industry advancements associated with cloud computing in the contextof supply chain rapidly proliferate. However, there is a lack of academic research that investigatesthe application of this technology from a theoretical standpoint. A significantpart of the literature explores the perceived advantages and disadvantages related to the decision-making process of the adoption of the specific technology, rather than the perceivedbenefits and challenges when the cloud has been already adopted and used. Furthermore,absent from the literature is a thorough understanding of the cloud-based applications inthe industry of 3PLs, and the perceived benefits and challenges not only from the userχsside but from the supply side as well. The research is limited referring to critical aspects ofcloud computing applied on 3PLs within a theoretical basis. Thus, in this study, the authorsaim at filling these gaps by exploring what types of cloud-based services are applied on3PLs, what are the perceived benefits and challenges from the 3PLs perspective as well asfrom their cloud providers/IT companies. Purpose: The purpose of this thesis is to investigate what cloud-based services are used inthe 3PL industry as well as the challenges and benefits perceived by the cloud providers of3PL firms and by the 3PL firms that use this technology. In order to gain a thorough understandingof this usage and grasp the full picture within the focal industry, the research isfocusing on the perspectives of three cloud providers and three 3PLs that use and/or providecloud based services. Method: : This is a qualitative study. The authors are making use of a case study strategywith six investigated companies. The majority of the data is gathered from semi-structuredinterviews, while documentary secondary data concerning basic companiesχ information,have been collected as well. The analysis of the findings is based on the revision of the settedapriori codes by the authors. A cross-analysis between 3PLs and cloud providers ofthose firms is being conducted in order to identify the perceived challenges and benefits ofcloud by both, within the 3PL industry. Conclusion: The findings of this thesis demonstrate Software as a Service (SaaS) and moreprecisely, transportation administration (TA) software, as the most prevailing cloud-basedsystem applied in the 3PL industry nowadays. It has been revealed that 3PLs benefit fromcloud technology in terms of cost savings, strategic flexibility, access to leading-edge IT resourcesand security, whereas the challenges faced are related to performance and strategicaspect. Furthermore, the authors identify and propose the different phases of cloud computingimplementation in the 3PL sector. Lastly, a model of perceived challenges and benefitsof cloud in 3PLs firms has been compiled and presented.
30

Adoption of Cloud Computing Services in an Illinois-Based Insurance Company

Polk, Nekerral 01 January 2019 (has links)
The decision to adopt cloud computing services should involve business units of an insurance company as well as information technology (IT) because cloud computing services are viewed as both a technology offering and business alternative. The purpose of this qualitative exploratory case study was to explore the strategies used by IT architects of an Illinois-based insurance company when adopting cloud computing services. The theory supporting this study was the technology acceptance model. The study's population consisted of IT architects from an Illinois-based insurance company that have used strategies to adopt cloud computing services. This study's data collection included semistructured interviews and review of organizational documents. Member checking with each participant increased the validity of this study's findings. Four major themes emerged from this study: strategies to adopt cloud computing services, strategies to adopt cloud services models, strategies to adopt cloud computing models, and concerns affecting the strategies to adopt cloud computing services. The study findings may assist IT architects in developing effective strategies to adopt cloud computing services for their respective business unit. This study might serve as a foundation for positive social change by decreasing customer concerns regarding critical information being compromised when adopting cloud computing services.

Page generated in 0.0275 seconds