Data centre optimisation enhanced by software defined networking

Contemporary Cloud Computing infrastructures are being challenged by an increasing demand for evolved cloud services characterised by heterogeneous performance requirements including real-time, data-intensive and highly dynamic workloads. The classical way to deal with dynamicity is to scale computing and network resources horizontally. However, these techniques must be coupled effectively with advanced routing and switching in a multi-path environment, mixed with a high degree of flexibility to support dynamic adaptation and live-migration of virtual machines (VMs). We propose a management strategy to jointly optimise computing and networking resources in cloud infrastructures, where Software Defined Networking (SDN) plays a key enabling role

Elastic admission control for federated cloud services

This paper presents a technique for admission control of a set of horizontally scalable services, and their optimal placement, into a federated Cloud environment. In the proposed model, the focus is on hosting elastic services whose resource requirements may dynamically grow and shrink, depending on the dynamically varying number of users and patterns of requests. The request may also be partially accommodated in federated external providers, if needed or more convenient. In finding the optimum allocation, the presented mechanism uses a probabilistic optimization model, which takes into account eco-efficiency and cost, as well as affinity and anti-affinity rules possibly in place for the components that comprise the services. In addition to modelling and solving the exact optimization problem, we also introduce a heuristic solver that exhibits a reduced complexity and solving time. We show evaluation results for the proposed technique under various scenarios

QoS probability distribution estimation for web services and service compositions

In this paper, we propose an approach to model the probability density function (PDF) of the QoS of a web service (QoWS) based on non-parametric statistical method. Mathematical formulas are designed to calculate the QoS distributions for service compositions (QoCS). Experiment has been done to show that the proposed QoWS distribution modeling approach is much more accurate than exiting methods. An accurate PDF estimation can be obtained for the QoCS if the PDF of the component QoWSs are modeled by the proposed method.8 page(s

The knowledge management in small and medium enterprises and the quality management approaches in service-oriented architecture

The thesis is organized into two different sections: the first one deals with the knowledge management (KM) in small and medium enterprises (SMEs), the second one deals with the quality management approaches in Service Oriented Architecture (SOA). The first research topic arises from the awareness that knowledge fertilization is crucial for SMEs competitiveness and to improve network collaboration. Nevertheless, while there is an abundance of studies describing how large companies are successfully exploiting knowledge management practices, regarding SMEs the framework is still fragmented. The Ph.D. program has been aimed at publishing two journal articles: the first one is a literature review, which provides the state of art of KM in SMEs and the second one is an empirical paper, which addresses the research questions emerging from the analysis of the literature review. The research questions concern the barriers hindering the spread of KM practices in SMEs, the main knowledge management systems (KMSs) adopted by SMEs and the impact of the use of KM practices on SME performance; they were subsequently addressed through a field analysis conducted on a sample of SMEs, adopting fuzzy set theory as methodology. Therefore the first section of this thesis is structured as a collection of these two published articles. The second section deals with the quality management approaches in Service-Oriented Architecture (SOA), this research topic arises from the needs to investigate services quality techniques since there is a vast literature concerning the software quality metrics within an object-oriented environment, but this framework cannot be applied to SOA systems. This study attempted to fill this gap presenting the results of a literature review on this topic; the outcomes of the review provide a valuable understanding of the best researched areas and the areas of SOA quality which are poorly investigated. In order to give an answer to one of the retrieved research questions emerging from the analysis of the literature review and concerning the lack of case studies, an empirical analysis on SOA services performance has been carried out in an important telecommunications company by an efficiency analysis. Finally the work’ conclusions are presented which sum up both the knowledge management prospect that the SOA prospect

SMEs Adoption of SaaS Cloud Services:A Novel Ontological Framework(Nigeria as a case Study).

The future of Information Technology lies in cloud computing, whose primary objective is to reduce the cost of IT services while increasing production output, availability, reliability, flexibility as well as a decrease in processing time. Owing to few exploratory studies that explain the adoption of cloud services, this research tends to understand the factors affecting cloud service adoption decision by SMEs in Nigeria. Also, it proposes a solution based framework to tackle the identified factors in view of promoting cloud service adoption by Nigerian SMEs. In view of the above, this thesis investigates the reason for slow adoption of cloud services with specific emphasis on Nigeria SMEs. Firstly, the existing literature in cloud service adoption by SME is examined based on Systematic Literature Review (SLR) method. This helps to inform the research gap in relation to cloud service adoption technique. Secondly, the thesis uses a mixed method approach integrating quantitative and qualitative methods to gather data through four stages of data gathering approach. The primary data gathering is based on quantitative (survey) stage 1 and qualitative (Focus Group) stage 2, which involves the studies identifying the cloud service adoption challenges specific to Nigeria SMEs. Furthermore, a solution framework CLOUDSME which includes an ontologically developed Decision Support System(DSS) is proposed to tackle the challenge identified in Primary data gathering stage 1and 2. The proposed framework consists of four phases: The first phase deals with gathering information on how various cloud services address dynamic SME user requirements identified in the primary data gathering stage, this phase forms the building block through which the framework is built upon. The second phase which is the prioritisation phase Adopts Analytical Hierarchical Process (AHP) approach to deal with the issue of complex comparison, also the third stage of data gathering (quantitative) is performed whereby a group interview is carried-out to compare and assign weights to service provider offering in addressing user requirements using pairwise comparison scale. The Third phase addressing the issue of cloud service ranking. In this phase, the major contribution of this research is introduced, whereby a new formalism is proposed using rational relationships to tackle the issue of rank reversal associated with the traditional AHP approach. The fourth phase of the framework is the development of the ontological proposed DSS which comprises of the information gathered in phase 1, 2 and 3. The proposed DSS promotes cloud service Knowledge management, service recommendation and service ranking toward cloud service adoption decision making by SME managers. The final stage of the research is the validation phase which comprises of construct validation. As well as user opinion and expert opinion and researcher opinion validation based on a survey (Quantitative) which makes up the fourth stage of the data gathering stages. The findings from the user opinion evaluation and validation prove the CLOUDSME has the capability to tackle the slow adoption of cloud services by Nigeria SMEs