8,585 research outputs found
Design and development of a hybrid flexible manufacturing system : a thesis presented in fulfilment of the requirements for the degree of Master of Technology at Massey University
Volumes 1 and 2 merged.The ability of a manufacturing environment to be able to modify itself and to incorporate a wide variety of heterogeneous multi-vendor devices is becoming a matter of increasing importance in the modern manufacturing enterprise. Many companies in the past have been forced to procure devices which are compatible with existing systems but are not as suitable as other less compatible devices. The inability to be able to integrate new devices into an existing company has made such enterprises dependent on one vendor and has decreased their ability to be able to respond to changes in the market. It is said that typically 60% of orders received in a company are new orders. Therefore the ability of a company to be able to reconfigure itself and respond to such demands and reintegrate itself with new equipment requirements is of paramount importance. In the past much effort has been made towards the integration of shop floor devices in industry whereby such devices can communicate with each other so that certain tasks are able to be achieved in a single environment. Up until recently however much of this was carried out in a very much improvised fashion with no real structure existing within the factory. This meant that once the factory was set up it became a hard-wired entity and extensibility and modiflability were difficult indeed. When formalised Computer Integrated Manufacturing (CIM) system architectures were developed it was found that although they solved many existing shortcomings there were inherent problems associated with these as well. What became apparent was that a fresh approach was required that took the advantages of existing architectures and combined them into an new architecture that not only capitalised on these advantages but also nullified the weaknesses of the existing systems. This thesis outlines the design of a new FMS architecture and its implementation in a factory environment on a PC based system
Meta-scheduling Issues in Interoperable HPCs, Grids and Clouds
Over the last years, interoperability among resources has been emerged as one of the most challenging research topics. However, the commonality of the complexity of the architectures (e.g., heterogeneity) and the targets that each computational paradigm including HPC, grids and clouds aims to achieve (e.g., flexibility) remain the same. This is to efficiently orchestrate resources in a distributed computing fashion by bridging the gap among local and remote participants. Initially, this is closely related with the scheduling concept which is one of the most important issues for designing a cooperative resource management system, especially in large scale settings such as in grids and clouds. Within this context, meta-scheduling offers additional functionalities in the area of interoperable resource management, this is because of its great agility to handle sudden variations and dynamic situations in user demands. Accordingly, the case of inter-infrastructures, including InterCloud, entitle that the decentralised meta-scheduling scheme overcome issues like consolidated administration management, bottleneck and local information exposition. In this work, we detail the fundamental issues for developing an effective interoperable meta-scheduler for e-infrastructures in general and InterCloud in particular. Finally, we describe a simulation and experimental configuration based on real grid workload traces to demonstrate the interoperable setting as well as provide experimental results as part of a strategic plan for integrating future meta-schedulers
Generic Framework for the Optimal Implementation of Flexibility Mechanisms in Large-Scale Smart Grids
This paper aims to provide the smart grid research community with an open and accessible
general mathematical framework to develop and implement optimal flexibility mechanisms in largescale
network applications. The motivation of this paper is twofold. On the one hand, flexibility
mechanisms are currently a hot topic of research, which is aimed tomitigate variation and uncertainty
of electricity demand and supply in decentralised grids with a high aggregated share of renewables.
On the other hand, a large part of such related research is performed by heuristic methods, which
are generally inefficient (such methods do not guarantee optimality) and difficult to extrapolate
for different use cases. Alternatively, this paper presents an MPC-based (model predictive control)
framework explicitly including a generic flexibility mechanism, which is easy to particularise to
specific strategies such as demand response, flexible production and energy efficiency services. The
proposed framework is benchmarked with other non-optimal control configurations to better show
the advantages it provides. The work of this paper is completed by the implementation of a generic
use case, which aims to further clarify the use of the framework and, thus, to ease its adoption by
other researchers in their specific flexibility mechanism applications
On Secure Workflow Decentralisation on the Internet
Decentralised workflow management systems are a new research area, where most
work to-date has focused on the system's overall architecture. As little
attention has been given to the security aspects in such systems, we follow a
security driven approach, and consider, from the perspective of available
security building blocks, how security can be implemented and what new
opportunities are presented when empowering the decentralised environment with
modern distributed security protocols. Our research is motivated by a more
general question of how to combine the positive enablers that email exchange
enjoys, with the general benefits of workflow systems, and more specifically
with the benefits that can be introduced in a decentralised environment. This
aims to equip email users with a set of tools to manage the semantics of a
message exchange, contents, participants and their roles in the exchange in an
environment that provides inherent assurances of security and privacy. This
work is based on a survey of contemporary distributed security protocols, and
considers how these protocols could be used in implementing a distributed
workflow management system with decentralised control . We review a set of
these protocols, focusing on the required message sequences in reviewing the
protocols, and discuss how these security protocols provide the foundations for
implementing core control-flow, data, and resource patterns in a distributed
workflow environment
A Taxonomy of Data Grids for Distributed Data Sharing, Management and Processing
Data Grids have been adopted as the platform for scientific communities that
need to share, access, transport, process and manage large data collections
distributed worldwide. They combine high-end computing technologies with
high-performance networking and wide-area storage management techniques. In
this paper, we discuss the key concepts behind Data Grids and compare them with
other data sharing and distribution paradigms such as content delivery
networks, peer-to-peer networks and distributed databases. We then provide
comprehensive taxonomies that cover various aspects of architecture, data
transportation, data replication and resource allocation and scheduling.
Finally, we map the proposed taxonomy to various Data Grid systems not only to
validate the taxonomy but also to identify areas for future exploration.
Through this taxonomy, we aim to categorise existing systems to better
understand their goals and their methodology. This would help evaluate their
applicability for solving similar problems. This taxonomy also provides a "gap
analysis" of this area through which researchers can potentially identify new
issues for investigation. Finally, we hope that the proposed taxonomy and
mapping also helps to provide an easy way for new practitioners to understand
this complex area of research.Comment: 46 pages, 16 figures, Technical Repor
Advanced security infrastructures for grid education
This paper describes the research conducted into advanced authorization infrastructures at the National e-Science Centre (NeSC) at the University of Glasgow and their application to support a teaching environment as part of the Dynamic Virtual Organisations in e-Science Education (DyVOSE) project. We outline the lessons learnt in teaching Grid computing and rolling out the associated security authorisation infrastructures, and describe our plans for a future, extended security infrastructure for dynamic establishment of inter-institutional virtual organisations (VO) in the education domain
A survey of self organisation in future cellular networks
This article surveys the literature over the period of the last decade on the emerging field of self organisation as applied to wireless cellular communication networks. Self organisation has been extensively studied and applied in adhoc networks, wireless sensor networks and autonomic computer networks; however in the context of wireless cellular networks, this is the first attempt to put in perspective the various efforts in form of a tutorial/survey. We provide a comprehensive survey of the existing literature, projects and standards in self organising cellular networks. Additionally, we also aim to present a clear understanding of this active research area, identifying a clear taxonomy and guidelines for design of self organising mechanisms. We compare strength and weakness of existing solutions and highlight the key research areas for further development. This paper serves as a guide and a starting point for anyone willing to delve into research on self organisation in wireless cellular communication networks
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