463 research outputs found
A Survey on Load Balancing Algorithms for VM Placement in Cloud Computing
The emergence of cloud computing based on virtualization technologies brings
huge opportunities to host virtual resource at low cost without the need of
owning any infrastructure. Virtualization technologies enable users to acquire,
configure and be charged on pay-per-use basis. However, Cloud data centers
mostly comprise heterogeneous commodity servers hosting multiple virtual
machines (VMs) with potential various specifications and fluctuating resource
usages, which may cause imbalanced resource utilization within servers that may
lead to performance degradation and service level agreements (SLAs) violations.
To achieve efficient scheduling, these challenges should be addressed and
solved by using load balancing strategies, which have been proved to be NP-hard
problem. From multiple perspectives, this work identifies the challenges and
analyzes existing algorithms for allocating VMs to PMs in infrastructure
Clouds, especially focuses on load balancing. A detailed classification
targeting load balancing algorithms for VM placement in cloud data centers is
investigated and the surveyed algorithms are classified according to the
classification. The goal of this paper is to provide a comprehensive and
comparative understanding of existing literature and aid researchers by
providing an insight for potential future enhancements.Comment: 22 Pages, 4 Figures, 4 Tables, in pres
Toward Customizable Multi-tenant SaaS Applications
abstract: Nowadays, Computing is so pervasive that it has become indeed the 5th utility (after water, electricity, gas, telephony) as Leonard Kleinrock once envisioned. Evolved from utility computing, cloud computing has emerged as a computing infrastructure that enables rapid delivery of computing resources as a utility in a dynamically scalable, virtualized manner. However, the current industrial cloud computing implementations promote segregation among different cloud providers, which leads to user lockdown because of prohibitive migration cost. On the other hand, Service-Orented Computing (SOC) including service-oriented architecture (SOA) and Web Services (WS) promote standardization and openness with its enabling standards and communication protocols. This thesis proposes a Service-Oriented Cloud Computing Architecture by combining the best attributes of the two paradigms to promote an open, interoperable environment for cloud computing development. Mutil-tenancy SaaS applicantions built on top of SOCCA have more flexibility and are not locked down by a certain platform. Tenants residing on a multi-tenant application appear to be the sole owner of the application and not aware of the existence of others. A multi-tenant SaaS application accommodates each tenant’s unique requirements by allowing tenant-level customization. A complex SaaS application that supports hundreds, even thousands of tenants could have hundreds of customization points with each of them providing multiple options, and this could result in a huge number of ways to customize the application. This dissertation also proposes innovative customization approaches, which studies similar tenants’ customization choices and each individual users behaviors, then provides guided semi-automated customization process for the future tenants. A semi-automated customization process could enable tenants to quickly implement the customization that best suits their business needs.Dissertation/ThesisDoctoral Dissertation Computer Science 201
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A grid computing framework for commercial simulation packages
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.An increased need for collaborative research among different organizations, together with continuing advances in communication technology and computer hardware, has facilitated the development of distributed systems that can provide users non-trivial access to geographically dispersed computing resources (processors, storage, applications, data, instruments, etc.) that are administered in multiple computer domains. The term grid computing or grids is popularly used to refer to such distributed systems. A broader definition of grid computing includes the use of computing resources within an organization for running organization-specific applications. This research is in the context of using grid computing within an enterprise to maximize the use of available hardware and software resources for processing enterprise applications. Large scale scientific simulations have traditionally been the primary benefactor of grid computing. The application of this technology to simulation in industry has, however, been negligible. This research investigates how grid technology can be effectively exploited by simulation practitioners using Windows-based commercially available simulation packages to model simulations in industry. These packages are commonly referred to as Commercial Off-The-Shelf (COTS) Simulation Packages (CSPs). The study identifies several higher level grid services that could be potentially used to support the practise of simulation in industry. It proposes a grid computing framework to investigate these services in the context of CSP-based simulations. This framework is called the CSP-Grid Computing (CSP-GC) Framework. Each identified higher level grid service in this framework is referred to as a CSP-specific service. A total of six case studies are presented to experimentally evaluate how grid computing technologies can be used together with unmodified simulation packages to support some of the CSP-specific services. The contribution of this thesis is the CSP-GC framework that identifies how simulation practise in industry may benefit from the use of grid technology. A further contribution is the recognition of specific grid computing software (grid middleware) that can possibly be used together with existing CSPs to provide grid support. With its focus on end-users and end-user tools, it is intended that this research will encourage wider adoption of grid computing in the workplace and that simulation users will derive benefit from using this technology
Analysis domain model for shared virtual environments
The field of shared virtual environments, which also
encompasses online games and social 3D environments, has a
system landscape consisting of multiple solutions that share great functional overlap. However, there is little system interoperability between the different solutions. A shared virtual environment has an associated problem domain that is highly complex raising difficult challenges to the development process, starting with the architectural design of the underlying system. This paper has two main contributions. The first contribution is a broad domain analysis of shared virtual environments, which enables developers to have a better understanding of the whole rather than the part(s). The second contribution is a reference domain model for discussing and describing solutions - the Analysis Domain Model
Supply chain management simulation: an overview
Synthesis of Vendome team research works (team belonging to GDR MACS - CNRS)Chapter 1 : Supply chain management simulation: an overvie
Distributed Simulation in Industry
Csaba Attila Boer was born in Satu Mare, Romania, on 29 October, 1975. He completed his secondary education at Kölcsey Ferenc High School, in Satu Mare, in 1994. In the same year he started his higher education at Babeş-Bolyai University, Faculty of Mathematics and Computer Science, Cluj-Napoca, Romania, where he received his B.Sc. degree in Computer Science, in 1998, and his M.Sc. degree with major in Information Systems, specialization Designing and Implementing Complex Systems, in 1999. During these years, he obtained fellowships at the Eötvös Lóránd University, and at the Computer and Automation Research Institute of the Hungarian Academy of Sciences, Budapest, Hungary within the Central European Exchange Program for University Studies (CEEPUS). Since 1999, he has been affiliated with the Computer Science Department, Faculty of Economics at Erasmus University Rotterdam, The Netherlands. There, he worked as a
researcher for one year, studying the storage and retrieval of discrete event simulation models, research that resulted in three scientific articles. Between 2000 and 2004, he was associated with the same department as a Ph.D. candidate aiming to research the area of distributed simulation and its application in industry. His topic being close to the research
carried out at the Faculty of Technology, Policy and Management, Delft University of Technology, and the BETADE research program, he started to collaborate with researchers from these groups, getting involved in two joint practical case study projects. This
collaboration resulted in seven joint scientific articles, presented at various international
conferences. Furthermore, Csaba has maintained international contacts with researchers
from the distributed simulation area. He has been invited twice to Brunel University, London to give a presentation concerning the application of distributed simulation in industry. Currently, he is working as a simulation consultant atGedistribueerde simulatie wordt binnen de defensie in brede kring geaccepteerd en toegepast, maar het heeft in de industrie geen voet aan de grond gekregen. In dit proefschrift onderzoeken we de redenen voor dit fenomeen door te bestuderen wat de industrie verwacht op het terrein van de gedistribueerde simulatie.
In het algemeen worden in de industrie simulatiemodellen ontworpen en ontwikkeld met COTS (“commercial-off-the-shelf”) simulatiepakketten. Echter, de bestaande architecturen voor gedistribueerde simulatie binnen defensie zijn niet gericht op het koppelen van modellen gebouwd met COTS simulatiepakketten. Om de industrie te motiveren gedistribueerde simulatie te accepteren en te gebruiken moet men derhalve ernaar streven het mogelijk te maken om modellen, die gebouwd zijn met deze pakketten, aan elkaar te koppelen zonder dat dat al te veel inspanning vereist van de modelbouwers.
Uitgaande van een onderzoek onder experts in dit domein, stellen we in dit proefschrift een pakket van eisen voor voor het ontwerp en ontwikkelen van gedistribueerde simulatiearchitecturen dat de industriegemeenschap zal motiveren om gedistribueerde simulatie te accepteren en toe te passen. Daarnaast presenteren we een lichtgewicht architectuur voor gedistribueerde simulatie die met succes toegepast is in twee industriële projecten, en die in grote mate voldoet aan het voorgestelde pakket van eisen.While distributed simulation is widely accepted and applied in defence, it has not gathered ground yet in industry. In this thesis we investigate the reasons behind this phenomenon by surveying the expectation of industry with respect to distributed simulation solutions.
Simulation models in industry are mainly designed and developed in commercial-off-the-shelf (COTS) simulation packages. The existing distributed simulation architectures in defence, however, do not focus on coupling models created in COTS simulation packages. Therefore, in order to motivate the industrial community to easily accept and use distributed simulation, one should strive to couple models built in these packages. Further, coupling these models should be possible without needing too much extra effort from modellers.
In this thesis, based on a survey with experts in domain, we propose a list of requirements for designing and developing distributed simulation architectures that would encourage the industrial community to accept and apply distributed simulation. Furthermore, we present a lightweight distributed simulation architecture which has been successfully applied in two industrial projects, and satisfies to a large extent the proposed requirements
Automated Scenario Generation Environment
Report describes IST\u27s investigation into the feasibility of automating the process of planning and scenario generation for large scale (joint level) simulation exercises and development of an architecture for that purpose
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