33 research outputs found

    SLA-based trust model for secure cloud computing

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    Cloud computing has changed the strategy used for providing distributed services to many business and government agents. Cloud computing delivers scalable and on-demand services to most users in different domains. However, this new technology has also created many challenges for service providers and customers, especially for those users who already own complicated legacy systems. This thesis discusses the challenges of, and proposes solutions to, the issues of dynamic pricing, management of service level agreements (SLA), performance measurement methods and trust management for cloud computing.In cloud computing, a dynamic pricing scheme is very important to allow cloud providers to estimate the price of cloud services. Moreover, the dynamic pricing scheme can be used by cloud providers to optimize the total cost of cloud data centres and correlate the price of the service with the revenue model of service. In the context of cloud computing, dynamic pricing methods from the perspective of cloud providers and cloud customers are missing from the existing literature. A dynamic pricing scheme for cloud computing must take into account all the requirements of building and operating cloud data centres. Furthermore, a cloud pricing scheme must consider issues of service level agreements with cloud customers.I propose a dynamic pricing methodology which provides adequate estimating methods for decision makers who want to calculate the benefits and assess the risks of using cloud technology. I analyse the results and evaluate the solutions produced by the proposed scheme. I conclude that my proposed scheme of dynamic pricing can be used to increase the total revenue of cloud service providers and help cloud customers to select cloud service providers with a good quality level of service.Regarding the concept of SLA, I provide an SLA definition in the context of cloud computing to achieve the aim of presenting a clearly structured SLA for cloud users and improving the means of establishing a trustworthy relationship between service provider and customer. In order to provide a reliable methodology for measuring the performance of cloud platforms, I develop performance metrics to measure and compare the scalability of the virtualization resources of cloud data centres. First, I discuss the need for a reliable method of comparing the performance of various cloud services currently being offered. Then, I develop a different type of metrics and propose a suitable methodology to measure the scalability using these metrics. I focus on virtualization resources such as CPU, storage disk, and network infrastructure.To solve the problem of evaluating the trustworthiness of cloud services, this thesis develops a model for each of the dimensions for Infrastructure as a Service (IaaS) using fuzzy-set theory. I use the Takagi-Sugeno fuzzy-inference approach to develop an overall measure of trust value for the cloud providers. It is not easy to evaluate the cloud metrics for all types of cloud services. So, in this thesis, I use Infrastructure as a Service (IaaS) as a main example when I collect the data and apply the fuzzy model to evaluate trust in terms of cloud computing. Tests and results are presented to evaluate the effectiveness and robustness of the proposed model

    SLA-Based Trust Model for Cloud Computing

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    Cloud computing is a new form of technology, which infrastructure, developing platform, software, and storage can be delivered as a service in a pay as you use cost model. However, for critical business application and more sensitive information, cloud providers must be selected based on high level of trustworthiness. In this paper, we present a trust model to evaluate cloud services in order to help cloud users select the most reliable resources. We integrate our previous work “conceptual SLA framework for cloud computing” with the proposed trust management model to present a new solution of defining the reliable criteria for the selection process of cloud providers

    Conceptual SLA Framework for Cloud Computing

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    Cloud computing has been a hot topic in the research community since 2007. In cloud computing the online services are conducted to be pay as you use. Services need not to be in a long term contract with service providers. Service level agreements (SLAs) are agreements signed between a service provider and other party like a service consumer, broker agent, or monitoring agent. Because cloud computing is recent technology providing many services for critical business applications, the need for reliable and flexible mechanisms to manage online contracts is very important. This paper presents the main criteria which should be considered at the stage of designing SLA in cloud computing. Also, we investigate the negotiation strategies between cloud provider and cloud consumer and propose our method to maintain the trust and reliability between each party which is involved in the negotiation processes

    Response time for cloud computing providers

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    Cloud services are becoming popular in terms of distributed technology because they allow cloud users to rent well-specified resources of computing, network, and storage infrastructure. Users pay for their use of services without needing to spend massive amounts for integration, maintenance, or management of the IT infrastructure. This creates the need for a reliable measurement methodology of the scalability for this type of new paradigm of services. In this paper, we develop performance metrics to measure and compare the scalability of the resources of virtualization on the cloud data centres. First, we discuss the need for a reliable method to compare the performance of cloud services among a number of various services being offered. Second, we develop a different type of metrics and propose a suitable methodology to measure the scalability using these types of metrics. We focus on the visualization resources such as CPU, storage disk, and network infrastructure. Finally, we compare well-known cloud providers using the proposed approach and conclude the recommendations. This type of research will help cloud consumers, before signing any official contract to use the desired services, to ascertain the ability and capacity of the cloud providers to deliver a particular service

    The association of preoperative cardiac stress testing with 30-day death and myocardial infarction among patients undergoing kidney transplantation

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    BACKGROUND:Although periodic cardiac stress testing is commonly used to screen patients on the waiting list for kidney transplantation for ischemic heart disease, there is little evidence to support this practice. We hypothesized that cardiac stress testing in the 18 months prior to kidney transplantation would not reduce postoperative death, total myocardial infarction (MI) or fatal MI. METHODS:Using the United States Renal Data System, we identified ESRD patients ≄40 years old with primary Medicare insurance who received their first kidney transplant between 7/1/2006 and 11/31/2013. Propensity matching created a 1:1 matched sample of patients with and without stress testing in the 18 months prior to kidney transplantation. The outcomes of interest were death, total (fatal and nonfatal) MI or fatal MI within 30 days of kidney transplantation. RESULTS:In the propensity-matched cohort of 17,304 patients, death within 30 days occurred in 72 of 8,652 (0.83%) patients who underwent stress testing and in 65 of 8,652 (0.75%) patients who did not (OR 1.07; 95% CI: 0.79-1.45; P = 0.66). MI within 30 days occurred in 339 (3.9%) patients who had a stress test and in 333 (3.8%) patients who did not (OR 1.03; 95% CI: 0.89-1.21; P = 0.68). Fatal MI occurred in 17 (0.20%) patients who underwent stress testing and 15 (0.17%) patients who did not (OR 0.97; 95% CI: 0.71-1.32; P = 0.84). CONCLUSION:Stress testing in the 18 months prior to kidney transplantation is not associated with a reduction in death, total MI or fatal MI within 30 days of kidney transplantation

    Evaluation of an intensive education program on the treatment of tobacco-use disorder for pharmacists: A study protocol for a randomized controlled trial

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    Background: Tobacco use is presently responsible for the death of over seven million people across the world. In Qatar, it is one of the main causes of premature deaths and preventable diseases. To reduce tobacco use, Qatar has ratified the World Health Organization (WHO)'s Framework Convention on Tobacco Control (FCTC) and has implemented many tobacco-control initiatives. In spite of these measures, tobacco use is still considered a public health threat in Qatar. Pharmacists practicing in retail/community pharmacy settings are often the first port of call for individuals requiring general health advice. Evidence has proven that they have a pivotal role in health promotion and disease prevention including tobacco cessation. However, pharmacists in Qatar are not actively involved in tobacco control and many have not received any education or training about smoking cessation counseling in the past. In an effort to build the capacity of pharmacists towards tobacco control in Qatar, the aim of the proposed study is to design, implement, and evaluate an intensive education program on tobacco dependence treatment for pharmacists in Qatar. Methods/design: The study will be a prospective randomized controlled trial comparing an intensive tobacco-related education program versus non-tobacco-related training on pharmacists' tobacco-use-related knowledge, attitudes, self-efficacy, and skills. Community pharmacists practicing in Qatar will be eligible for participation in the study. A random sample of pharmacists will be selected for participation. Consenting participants will be randomly allocated to intervention or control groups. Participants in the intervention group will receive an intensive education program delivered by a multi-disciplinary group of educators, researchers, and clinicians with expertise in tobacco cessation. A short didactic session on a non-tobacco-related topic will be delivered to pharmacists in the control group. The study has two primary outcomes: post-intervention tobacco-related knowledge and post-intervention skills for tobacco cessation assessed using a multiple-choice-based evaluation instrument and an Objective Structured Clinical Examination (OSCE), respectively. The secondary study outcomes are post-intervention attitudes towards tobacco cessation and self-efficacy in tobacco-cessation interventions assessed using a survey instrument. An additional secondary study outcome is the post-intervention performance difference in relation to tobacco-cessation skills in the practice setting assessed using the simulated client approach. Discussion: If demonstrated to be effective, this education program will be considered as a model that Qatar and the Middle East region can apply to overcome the burden of tobacco-use disorder. Trial registration: ClinicalTrials.gov, ID: NCT03518476. Registered on 8 May 2018. Version 1/22 June 2018. 2019 The Author(s).ASHP: American Society of Health-System Pharmacists; ATTUD: Association for the Treatment of Tobacco use and Dependence; CE: Continuous education; CPG: Clinical practice guidelines; FCTC: Framework Convention on Tobacco Control; FIP: International Pharmaceutical Federation; GATS: Global Adult Tobacco Survey; GYTS: Global Youth Tobacco Survey; HMC: Hamad Medical Corporation; MCQ: Multiple choice question; ME: Middle East; NRT: Nicotine replacement therapy; OSCE: Objective Structured Clinical Examination; PBL: Problem-based learning; QCHP: Qatar Council for Healthcare Practitioners; QU: Qatar University; SPIRIT: Standard Protocol Items: Recommendations for Interventional Trials; SPSS: Statistical Package of Social Sciences; TTM: Transtheoretical model; WHO: World Health OrganizationScopu

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    A survey on SLA and performance measurement in cloud computing

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    Cloud computing has changed the strategy used for providing distributed services to many business and government agents. Cloud computing delivers scalable and on-demand services to most users in different domains. However, this new technology has also created many challenges for service providers and customers, especially for those users who already own complicated legacy systems. This paper reviews the challenges related to the concepts of trust, SLA management, and cloud computing. We begin with a survey of cloud computing architecture. Then, we discuss existing frameworks of service level agreements in different domains such as web services and grid computing. In the last section, we discuss the advantages and limitations of current performance measurement models for SOA, distributed systems, grid computing, and cloud services. Finally, we summarize and conclude our work

    Service level agreement for distributed services: a review

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    Cloud computing has change the strategy of the way of providing distributed services for many business and government agents. Cloud computing delivers a scalable and on demand services for most users in different domains. This new technology brings many challenges to service providers and customers especially for users who already own complicated legacy systems. This paper examines challenges related to the concepts of trust, SLA management, and cloud computing. We focus on SLA definition in cloud computing to achieve the aim of presenting a clear structure of SLA for cloud users and improve the way of building trustworthy relationship between service provider and customer. In this paper, we start with the presenting the importance of cloud computing and the need of SLA for cloud computing. Then, survey of cloud computing architecture is provided. Then, we discuss existing frameworks of service level agreements in different domains such as web services and grid computing. The last part of literature review discusses advantages and limitations of performance measurement models in SOA, distributed systems, grid computing, and cloud services. Finally, we summarize and conclude our work
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