Institutions
|
About Us
|
Help
|
Gaeilge
0
1000
Home
Browse
Advanced Search
Search History
Marked List
Statistics
A
A
A
Author(s)
Institution
Publication types
Funder
Year
Limited By:
Subject = networks;
20 items found
Sort by
Title
Author
Item type
Date
Institution
Peer review status
Language
Order
Ascending
Descending
25
50
100
per page
Bibtex
CSV
EndNote
RefWorks
RIS
XML
Displaying Results 1 - 20 of 20 on page 1 of 1
Marked
Mark
A Combinatorial Optimisation Approach to the Design of Dual Parented Long-Reach Passive Optical Networks
(2011)
RUFFINI, MARCO
A Combinatorial Optimisation Approach to the Design of Dual Parented Long-Reach Passive Optical Networks
(2011)
RUFFINI, MARCO
Abstract:
We present an application focused on the design of resilient long-reach passive optical networks. We specifically consider dual parented networks whereby each customer must be connected to two metro sites via a local exchange sites. An important property of such a placement is resilience to single metro node failure. The objective of the application is to determine the optimal position of a set of metro-nodes such that the total optical fibre length is minimised. We prove that the decision variant of this problem is NP-Complete. We present three alternative combinatorial optimisation approaches to finding an optimal metro node placement using: a mixed integer linear programming formulation of the problem; a hybrid approach that uses clustering as a preprocessing step; and, finally, a local search approach. We consider a detailed case-study based on a network for Ireland. The hybrid approach scales well and finds solutions that are close to optimal, with a runtime that is two orders-of-ma...
http://hdl.handle.net/2262/63929
Marked
Mark
A Cross-Layer Modification to the DSR Routing Protocol in Wireless Mesh Networks
(2011)
Ramadhan, Mustafa, (Thesis)
A Cross-Layer Modification to the DSR Routing Protocol in Wireless Mesh Networks
(2011)
Ramadhan, Mustafa, (Thesis)
Abstract:
<p>A cross-layer modification to the DSR routing protocol that finds high throughput paths in WMNs has been introduced in this work. The Access Efficiency Factor (AEF) has been introduced in this modification as a local congestion avoidance metric for the DSR routing mechanism as an alternative to the hop count (Hc) metric. In this modification, the selected path is identified by finding a path with the highest minimum AEF (max_min_AEF) value. The basis of this study is to compare the performance of the Hc and max_min_AEF as routing metrics for the DSR protocol in WMNs using the OPNET modeler. Performance comparisons between max_min_AEF, Metric Path (MP), and the well known ETT metrics are also carried out in this work. The results of this modification suggest that employing the max_min_AEF as a routing metric outperforms the Hc, ETT, and MP within the DSR protocol in WMNs in terms of throughput. This is because the max_min_AEF is based upon avoiding directing traffic through ...
http://arrow.dit.ie/engdoc/33
Marked
Mark
A latent space mapping for link prediction
(2010)
Brew, Anthony; Salter-Townshend, Michael
A latent space mapping for link prediction
(2010)
Brew, Anthony; Salter-Townshend, Michael
Abstract:
Network modeling can be approached using either discriminative or probabilistic models. In the task of link prediction a probabilistic model will give a probability for the existence of a link; while in some scenarios this may be beneficial, in others a hard discriminative boundary needs to be set. Hence the use of a discriminative classifier is preferable. In domains such as image analysis and speaker recognition, probabilistic models have been used as a mechanism from which features can be extracted. This paper examines using a probabilistic model built on the entire graph to extract features to predict the existence of unknown links between two nodes. It demonstrates how features extracted from the model as well as the predicted probability of a link existing can aid the classification process.
http://hdl.handle.net/10197/2895
Marked
Mark
Architectures for person to person communications in disaggregated networks
(2006)
ARGYROUDIS, PATROKLOS; DOYLE, LINDA; O'MAHONY, DONAL EDWARD
Architectures for person to person communications in disaggregated networks
(2006)
ARGYROUDIS, PATROKLOS; DOYLE, LINDA; O'MAHONY, DONAL EDWARD
Abstract:
peer-reviewed
Current telecommunications systems allocate identifiers to devices, and end-points. While this has worked well thus far, we believe that as more devices are used to access these systems, people have a tendency to be mobile across these devices. In this article we review current systems and introduce a new model for telecommunications, which we term person to person communications. Under this new model people are allocated identifiers, which they may associate with any number of devices. We outline why we believe this to be a more effective model than the current one
http://hdl.handle.net/2262/17059
Marked
Mark
Bond percolation on a class of clustered random networks
(2009)
Gleeson, James P.
Bond percolation on a class of clustered random networks
(2009)
Gleeson, James P.
Abstract:
Science Foundation Ireland: 06/IN.1/I366 and MACSI 06/MI/005
Analytical results are derived for the bond percolation threshold and the size of the giant connected component in a class of random networks with nonzero clustering. The network's degree distribution and clustering spectrum may be prescribed and theoretical results match well with numerical simulations on both synthetic and real-world networks.
http://hdl.handle.net/10344/347
Marked
Mark
Brokerage or friendship? politics and networks in Ireland
(1992)
Komito, Lee
Brokerage or friendship? politics and networks in Ireland
(1992)
Komito, Lee
Abstract:
Studies of Irish politics have often emphasised clientelist relations between voters and politicians. A survey carried out in the 1970s indicates that the importance of politicians has been overstated. A significant percentage of people chose non-political figures as brokers between themselves and the state. Differences in urban and rural community social structures, which are not reflections of age, education, or socio-economic status, correlate with different brokerage choices. Such findings cast doubt on both modernization and dependency explanations of brokerage. Further research on social networks of friendship and exchange are necessary, since informal personal networks emerge as important links between individuals and the state.
http://hdl.handle.net/2262/64868
Marked
Mark
Capitals and commitment. The case of a local learning and employment network.
(2009)
Kamp, Annelies
Capitals and commitment. The case of a local learning and employment network.
(2009)
Kamp, Annelies
Abstract:
This article draws on research undertaken with a Local Learning and Employment Network (LLEN) in the state of Victoria, Australia. LLEN are networks that were implemented by the state government in 2001 to undertake community capacity building through which the outcomes of young people aged 15-19 in education, training and employment would be enhanced. In 2008, in the context of an enhanced federal commitment to social inclusion through ‘joining-up’, the Victorian experience provides insights on the implications of such policy initiatives. Drawing on Bourdieu’s discussion of the forms of capital and Granovetter’s notion of the strength of weak ties, I argue that stores of economic, cultural and social capital as outlined by Bourdieu were necessary, but insufficient, for LLEN to achieve the objectives with which they were charged given the failure of government to follow through on the implications of its policies. I argue for a commitment on the part of all stakeholders to realise t...
http://doras.dcu.ie/16247/
Marked
Mark
Detecting highly overlapping communities with Model-based Overlapping Seed Expansion
(2010)
McDaid, Aaron; Hurley, Neil J.
Detecting highly overlapping communities with Model-based Overlapping Seed Expansion
(2010)
McDaid, Aaron; Hurley, Neil J.
Abstract:
As research into community finding in social networks progresses, there is a need for algorithms capable of detecting overlapping community structure. Many algorithms have been proposed in recent years that are capable of assigning each node to more than a single community. The performance of these algorithms tends to degrade when the ground-truth contains a more highly overlapping community structure, with nodes assigned to more than two communities. Such highly overlapping structure is likely to exist in many social networks, such as Facebook friendship networks. In this paper we present a scalable algorithm, MOSES, based on a statistical model of community structure, which is capable of detecting highly overlapping community structure, especially when there is variance in the number of communities each node is in. In evaluation on synthetic data MOSES is found to be superior to existing algorithms, especially at high levels of overlap. We demonstrate MOSES on real social network...
http://hdl.handle.net/10197/2404
Marked
Mark
Development of probalistic techniques for network assessment with significant wind generation
(2007)
Mumtaz, Asim, (Thesis)
Development of probalistic techniques for network assessment with significant wind generation
(2007)
Mumtaz, Asim, (Thesis)
Abstract:
<p>Due to increasing awareness of global warming and high energy costs, more electrical power is being generated by using renewable sources. However some of these sources are not as predictable as conventional generation and they also lack the ability to be dispatched in the same way. The increase in the amount of wind power connected to transmission networks has been significant in some countries. But due to the stochastic nature of wind power, it is difficult to predict exactly how much power can be generated at any given time. This variable nature of wind power can cause line overloading and high voltage problems. To overcome these problems transmission networks can be upgraded but the cost of upgrade can make it uneconomical to accommodate wind power. Although wind turbines have very high availability rates, their ability to generate wind power depends on the wind speed. Most wind farms have capacity factors in the range of 30%-40%. The probability of wind farms operating ...
http://arrow.dit.ie/engmas/28
Marked
Mark
Effect of Free Bandwidth on VoIP Performance in 802.11b WLAN Networks
(2006)
Narbutt, Miroslaw; Davis, Mark
Effect of Free Bandwidth on VoIP Performance in 802.11b WLAN Networks
(2006)
Narbutt, Miroslaw; Davis, Mark
Abstract:
<p>In this paper we experimentally study the relationship between bandwidth utilization in the wireless LAN and the quality of VoIP calls transmitted over the wireless medium. Specifically we evaluate how the amount of free bandwidth decreases as the number of calls increases and how this influences transmission impairments (i.e. delay, loss and jitter) and thus degrades call quality. We show that the amount of free bandwidth is a good indicator for predicting VoIP call quality.</p>
http://arrow.dit.ie/commcon/20
Marked
Mark
Evaluating business networks : the case of Ireland
(2010)
Lynch, Nicola
Evaluating business networks : the case of Ireland
(2010)
Lynch, Nicola
Abstract:
Business networks are used by firms as a tool for organising interdependent business activities, where such networks are defined as a cooperative arrangement between independent business organisations that can vary from informal to formal exchanges of resources and information. Although the benefits and costs associated with business network membership have been highlighted in the literature, there is a distinct lack of discussion regarding appropriate evaluation frameworks to estimate the impact of business network membership on firm performance. This thesis addresses this specific issue through the development of an ex-post evaluation framework to estimate the impact of business network membership on firm performance. This research therefore makes a key methodological contribution through the development of an evaluation framework, while it also fills a gap in the international business network and evaluation literatures. The Irish case is used as a laboratory where data is gather...
http://hdl.handle.net/10344/1617
Marked
Mark
Exclusivity, Externalities & Easements: Dynamic Spectrum Access and Coasean Bargaining
(2007)
FORDE, TIM; DOYLE, LINDA
Exclusivity, Externalities & Easements: Dynamic Spectrum Access and Coasean Bargaining
(2007)
FORDE, TIM; DOYLE, LINDA
Abstract:
peer-reviewed
This paper explores the possibility of realising Coasean bargains to remove the presence of externalities in a libertarian system of exclusive spectrum rights through the creation of various economically motivated easements. We advocate that dynamic spectrum access (DSA) techniques can be used to enable rights holders reduce or eliminate the effects of externalities through local bargaining. Many of the objections to the promotion of marketbased exclusive-rights assignment systems concern the ability of rights holders to enforce their spectrum rights, so as to extract maximal value. In an increasingly fragmented and less-regulated spectrum landscape, there will be an inevitable chafing of rights at the boundaries between the users of neighbouring blocks of spectrum; the spectral activities of one network may impinge on the ability of a neighbouring network to extract maximum value from its exclusively assigned spectrum. Nonetheless, it is argued that it is possible...
http://hdl.handle.net/2262/19024
Marked
Mark
Extending uncertainty formalisms to linear constraints and other complex formalisms
(2008)
Wilson, Nic
Extending uncertainty formalisms to linear constraints and other complex formalisms
(2008)
Wilson, Nic
Abstract:
Science Foundation Ireland (00/PI.1/C075); Science Foundation Ireland (05/IN/I886)
Accepted Version
Linear constraints occur naturally in many reasoning problems and the information that they represent is often uncertain. There is a difficulty in applying AI uncertainty formalisms to this situation, as their representation of the underlying logic, either as a mutually exclusive and exhaustive set of possibilities, or with a propositional or a predicate logic, is inappropriate (or at least unhelpful). To overcome this difficulty, we express reasoning with linear constraints as a logic, and develop the formalisms based on this different underlying logic. We focus in particular on a possibilistic logic representation of uncertain linear constraints, a lattice-valued possibilistic logic, an assumption-based reasoning formalism and a Dempster-Shafer representation, proving some fundamental results for these extended systems. Our results on extending uncertainty formalisms also ap...
http://hdl.handle.net/10468/1118
Marked
Mark
Government support for the development of regional food clusters: evidence from Alberta, Canada
(2011)
Steiner, Bodo E.; Ali, Jolene
Government support for the development of regional food clusters: evidence from Alberta, Canada
(2011)
Steiner, Bodo E.; Ali, Jolene
Abstract:
Accepted Version
This paper analyses government support for networking and regional cluster growth in the food sector. It is, to the best of our knowledge, the first paper to provide a literature review of studies on regional food clusters, focusing on key features that characterise successful regional food clusters. The review compares key characteristics of such clusters with characteristics of clusters from other industrial sectors. The insights from these studies on clustering success and the role of government are contrasted with empirical evidence on government support for clustering in the Canadian food sector, specifically in the province of Alberta. The empirical evidence is based on two small industry surveys, one conducted in March 2005, and the second in August 2009. Considering this empirical evidence, we have little support for an emerging food (innovation) cluster in Alberta, and little evidence for effective government support toward food cluster development in A...
http://hdl.handle.net/10468/434
Marked
Mark
Impact of bias current distribution on the noise figure and power saturation of a multicontact semiconductor optical amplifier
(2011)
LENNOX, ROBERT; BRADLEY, LOUISE
Impact of bias current distribution on the noise figure and power saturation of a multicontact semiconductor optical amplifier
(2011)
LENNOX, ROBERT; BRADLEY, LOUISE
Abstract:
We present an experimental investigation of a multicontact semiconductor optical amplifier. This first-generation device allows for direct control of the carrier density profile along the length of the waveguide. This is used to control the device noise figure, with a minimum value of 5 dB observed at a gain of 15 dB for an optimum carrier density profile. The opposite carrier density profile results in an increase of the power saturation by 3 dB.
http://hdl.handle.net/2262/59312
Marked
Mark
Improving Multicast Communications Over Wireless Mesh Networks
(2010)
Keegan, Brian, (Thesis)
Improving Multicast Communications Over Wireless Mesh Networks
(2010)
Keegan, Brian, (Thesis)
Abstract:
<p>In wireless mesh networks (WMNs) the traditional approach to shortest path tree based multicasting is to cater for the needs of the poorest performing<br />node i.e. the maximum permitted multicast line rate is limited to the lowest line rate used by the individual Child nodes on a branch. In general, this means<br />fixing the line rate to its minimum value and fixing the transmit power to its maximum permitted value. This simplistic approach of applying a single multicast rate for all nodes in the multicast group results in a sub-optimal trade-off between the mean network throughput and coverage area that does not allow for high bandwidth multimedia applications to be supported. By relaxing this constraint and allowing multiple line rates to be used, the mean network throughput can be improved. This thesis presents two methods that aim to increase the mean network throughput through the use of multiple line rates by the forwarding nodes. This is achieved by id...
http://arrow.dit.ie/engdoc/31
Marked
Mark
MeshScan: a Fast and Efficient Handoff Scheme for IEEE 802.11 Wireless Mesh Networks
(2010)
Chen, Yin, (Thesis)
MeshScan: a Fast and Efficient Handoff Scheme for IEEE 802.11 Wireless Mesh Networks
(2010)
Chen, Yin, (Thesis)
Abstract:
<p>As a next generation network solution, Wireless Mesh Networks (WMN) provides fast Internet access to a large area, which is from university campus to city scale. In order to provide an uninterrupted Internet experience to a mobile client, a process called handoff is required to maintain the network connection from one Mesh Node (MN) to another MN. Ideally, handoff should be completely transparent to mobile users. A critical application like VoIP will require a handoff capability that transfers a call from one mesh node (MN) to another in less than 50 msec. However the current IEEE 802.11 standards do not address the handoff well. Studies have revealed that standard handoff on IEEE 802.11 WLANs incurs a latency of the order of hundreds of milliseconds to several seconds. Moreover, the discovery step in the handoff process accounts for more than 99% of this latency. The study addresses the latency in the discovery step by introducing an efficient and powerful client-side scan...
http://arrow.dit.ie/engmas/37
Marked
Mark
Supply Chain Management Diffusion Among Firms in the Republic of Ireland
(2007)
Sweeney, Edward; Wagner, Claudia-Maria; Huber, Bernd
Supply Chain Management Diffusion Among Firms in the Republic of Ireland
(2007)
Sweeney, Edward; Wagner, Claudia-Maria; Huber, Bernd
Abstract:
<p>The changing business environment has sharpened the focus on the need for robust approaches to supply chain management (SCM). This is particularly the case for Ireland which has a natural disadvantage of a location peripheral to significant markets and sources of raw material which result in higher transport costs. Therefore, in order to gain unique insights of current levels of awareness / diffusion of SCM and the potential impact SCM could have on the competitiveness, a survey was conducted among 776 firms in the Republic of Ireland. The empirical results suggest that there is a need for more widespread adoption of supply chain management among Irish firms. Many firms in Ireland pay lip service to the importance of SCM elements and objectives but the majority of firms, about two thirds, have only a passing understanding of what constitutes SCM. Only 25% adopt SCM programmes and only 9% of Irish companies have a specialised SCM or logistics manager. Also worrying is the ...
http://arrow.dit.ie/nitlcon/14
Marked
Mark
Teamwork and Collaboration in Cognitive Wireless Networks
(2007)
DOYLE, LINDA; NOLAN, KEITH EDWARD
Teamwork and Collaboration in Cognitive Wireless Networks
(2007)
DOYLE, LINDA; NOLAN, KEITH EDWARD
Abstract:
This article looks at the principles and significant potential of teamwork in cognitive networks. These concepts represent a new evolutionary stage in the development of cognitive radio and cognitive networks, where wireless communication progresses from an individual, device-centric approach toward group and team behavior. This creates the potential for more effective and more robust communication solutions when deemed necessary. The key elements of effective cognitive network teamwork are introduced in this article. These include group formation, distributed co-ordination, goal and role identification, accountability, and reward mechanisms for the outcomes of team behavior. The value of the group as a whole can be increased rather than individual gain for only a single device. Focusing on an early experimental cognitive network teamwork testbed designed by CTVR, this article outlines the potential of developing cognitive networks that can work as a team. Potential applications and...
http://hdl.handle.net/2262/10899
Marked
Mark
Variational Bayesian inference for the Latent Position Cluster Model
(2009)
Salter-Townshend, Michael; Murphy, Thomas Brendan
Variational Bayesian inference for the Latent Position Cluster Model
(2009)
Salter-Townshend, Michael; Murphy, Thomas Brendan
Abstract:
Many recent approaches to modeling social networks have focussed on embedding the actors in a latent “social space”. Links are more likely for actors that are close in social space than for actors that are distant in social space. In particular, the Latent Position Cluster Model (LPCM) [1] allows for explicit modelling of the clustering that is exhibited in many network datasets. However, inference for the LPCM model via MCMC is cumbersome and scaling of this model to large or even medium size networks with many interacting nodes is a challenge. Variational Bayesian methods offer one solution to this problem. An approximate, closed form posterior is formed, with unknown variational parameters. These parameters are tuned to minimize the Kullback-Leibler divergence between the approximate variational posterior and the true posterior, which known only up to proportionality. The variational Bayesian approach is shown to give a computationally efficient way of fitting the LPCM. The appro...
http://hdl.handle.net/10197/2756
Displaying Results 1 - 20 of 20 on page 1 of 1
Bibtex
CSV
EndNote
RefWorks
RIS
XML
Institution
Dublin City University (1)
Dublin Institute of Technology (6)
Trinity College Dublin (6)
University College Cork (2)
University College Dublin (3)
University of Limerick (2)
Item Type
Conference item (8)
Doctoral thesis (3)
Journal article (7)
Master thesis (research) (2)
Peer Review Status
Peer-reviewed (18)
Non-peer-reviewed (1)
Unknown (1)
Year
2011 (4)
2010 (5)
2009 (3)
2008 (1)
2007 (4)
2006 (2)
1992 (1)
built by Enovation Solutions