67,099 research outputs found
Smart Grid Technologies in Europe: An Overview
The old electricity network infrastructure has proven to be inadequate, with respect to modern challenges such as alternative energy sources, electricity demand and energy saving policies. Moreover, Information and Communication Technologies (ICT) seem to have reached an adequate level of reliability and flexibility in order to support a new concept of electricity networkâthe smart grid. In this work, we will analyse the state-of-the-art of smart grids, in their technical, management, security, and optimization aspects. We will also provide a brief overview of the regulatory aspects involved in the development of a smart grid, mainly from the viewpoint of the European Unio
Recommended from our members
Assessing the value dimensions of outsourced maintenance services
Purpose
- The purpose of this paper is to investigate the diverse nature of tangible and intangible value dimensions that contribute to customers' perception of value from outsourced maintenance services.
Design/methodology/approach
- A multiple case study approach has been adopted. Repertory grid, an in-depth structured interviewing technique, has been used in order to draw out the respondents' hidden constructs in evaluating outsourced maintenance services. Data have been collected from four customer organizations of outsourced maintenance services, and a total of 33 interviews have been undertaken.
Findings
- The paper has identified a range of tangible and intangible value dimensions that are of importance in maintenance outsourcing decision making. The most important value dimensions for maintenance outsourcing were found to be specialist knowledge, accessibility (of the service provider), relational dynamic, range of products and services, delivery, pricing and locality. Although the paper has identified the most important value dimensions the paper also emphasizes the need to take into account the full range of value dimensions in order to understand the whole value pattern in an organization.
Practical implications
- The results will be of use for maintenance service providers to help them to improve value-adding capacity of maintenance services. The results can also be applied by customers to help them assess the value they receive from outsourced maintenance services.
Originality/value
- A different perspective on maintenance outsourcing value is provided. The value patterns in different organizations and the viewpoints of respondents in different organizational roles are described. The dynamic nature of these tangible or intangible values over time and their interrelationships has also been explored
Recommended from our members
A classification of emerging and traditional grid systems
The grid has evolved in numerous distinct phases. It started in the early â90s as a model of metacomputing in which supercomputers share resources; subsequently, researchers added the ability to share data. This is usually referred to as the first-generation grid. By the late â90s, researchers had outlined the framework for second-generation grids, characterized by their use of grid middleware systems to âglueâ different grid technologies together. Third-generation grids originated in the early millennium when Web technology was combined with second-generation grids. As a result, the invisible grid, in which grid complexity is fully hidden through resource virtualization, started receiving attention. Subsequently, grid researchers identified the requirement for semantically rich knowledge grids, in which middleware technologies are more intelligent and autonomic. Recently, the necessity for grids to support and extend the ambient intelligence vision has emerged. In AmI, humans are surrounded by computing technologies that are unobtrusively embedded in their surroundings.
However, third-generation gridsâ current architecture doesnât meet the requirements of next-generation grids (NGG) and service-oriented knowledge utility (SOKU).4 A few years ago, a group of independent experts, arranged by the European Commission, identified these shortcomings as a way to identify potential European grid research priorities for 2010 and beyond. The experts envision grid systemsâ information, knowledge, and processing capabilities as a set of utility services.3 Consequently, new grid systems are emerging to materialize these visions. Here, we review emerging grids and classify them to motivate further research and help establish a solid foundation in this rapidly evolving area
Formal Aspects of Grid Brokering
Coordination in distributed environments, like Grids, involves selecting the
most appropriate services, resources or compositions to carry out the planned
activities. Such functionalities appear at various levels of the infrastructure
and in various means forming a blurry domain, where it is hard to see how the
participating components are related and what their relevant properties are. In
this paper we focus on a subset of these problems: resource brokering in Grid
middleware. This paper aims at establishing a semantical model for brokering
and related activities by defining brokering agents at three levels of the Grid
middleware for resource, host and broker selection. The main contribution of
this paper is the definition and decomposition of different brokering
components in Grids by providing a formal model using Abstract State Machines
Structural Vulnerability Analysis of Electric Power Distribution Grids
Power grid outages cause huge economical and societal costs. Disruptions in
the power distribution grid are responsible for a significant fraction of
electric power unavailability to customers. The impact of extreme weather
conditions, continuously increasing demand, and the over-ageing of assets in
the grid, deteriorates the safety of electric power delivery in the near
future. It is this dependence on electric power that necessitates further
research in the power distribution grid security assessment. Thus measures to
analyze the robustness characteristics and to identify vulnerabilities as they
exist in the grid are of utmost importance. This research investigates exactly
those concepts- the vulnerability and robustness of power distribution grids
from a topological point of view, and proposes a metric to quantify them with
respect to assets in a distribution grid. Real-world data is used to
demonstrate the applicability of the proposed metric as a tool to assess the
criticality of assets in a distribution grid
- âŠ