58,498 research outputs found
Radiation tolerant silicon nitride insulated gate field effect transistors
Metal-Insulated-Semiconductor Field Effect Transistor /MISFET/ device uses a silicon nitride passivation layer over a thin silicon oxide layer to enhance the radiation tolerance. It is useful in electronic systems exposed to space radiation environment or the effects of nuclear weapons
Stations, trains and small-world networks
The clustering coefficient, path length and average vertex degree of two
urban train line networks have been calculated. The results are compared with
theoretical predictions for appropriate random bipartite graphs. They have also
been compared with one another to investigate the effect of architecture on the
small-world properties.Comment: 6 pages, prepared in RevTe
Large-scale structure of time evolving citation networks
In this paper we examine a number of methods for probing and understanding
the large-scale structure of networks that evolve over time. We focus in
particular on citation networks, networks of references between documents such
as papers, patents, or court cases. We describe three different methods of
analysis, one based on an expectation-maximization algorithm, one based on
modularity optimization, and one based on eigenvector centrality. Using the
network of citations between opinions of the United States Supreme Court as an
example, we demonstrate how each of these methods can reveal significant
structural divisions in the network, and how, ultimately, the combination of
all three can help us develop a coherent overall picture of the network's
shape.Comment: 10 pages, 6 figures; journal names for 4 references fixe
Globalisation and insecurity
We construct a simple model of the e€ect of increased interna-tional openness on risk bearing in an environment in which the onlyrisk-sharing institutions are self-enforcing agreements. We showhow increased openness can weaken long-term relationships, andhence risk sharing, by increasing the e€ectiveness of the market,much as some critics of globalization have argued. However, theharm thereby done is tempered by the fact that in order to havesuch a negative indirect e€ect, openness must have a direct e€ectthat reduces risk. It is shown that on balance, globalization reducesrisk and raises welfare for those in small countries, but increases riskand reduces welfare for those in large countries. We construct a simple model of the e€ect of increased interna-tional openness on risk bearing in an environment in which the onlyrisk-sharing institutions are self-enforcing agreements. We showhow increased openness can weaken long-term relationships, andhence risk sharing, by increasing the e€ectiveness of the market,much as some critics of globalization have argued. However, theharm thereby done is tempered by the fact that in order to havesuch a negative indirect e€ect, openness must have a direct e€ectthat reduces risk. It is shown that on balance, globalization reducesrisk and raises welfare for those in small countries, but increases riskand reduces welfare for those in large countries
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Modelling the effects of mall atmospherics on shoppersâ approach behaviors
Despite previous work, researchers still do not fully understand the mechanisms by
which environmental stimuli influence emotions and affect behavior. This paper attempts to
address this knowledge gap by modelling the effects of a stimulus on emotions and behavior
within the context of a shopping mall and retail stores. We evaluate a stimulus-response
model based on the influence of perceptions on shoppersâ moods, which in turn influence
approach behaviors. A structured questionnaire survey of actual shoppers in a real mall
environment (n=315) was analysed by structural equation analysis. The exemplar stimulus
consisted of a Captive Audience Network (CAN or private plasma screen network) â a topic
that has been little researched to date. The influence of the CAN was small but significant.
The findings have implications for practitioners as even small changes in image can have a
substantial effect on profitability
Concentric Characterization and Classification of Complex Network Nodes: Theory and Application to Institutional Collaboration
Differently from theoretical scale-free networks, most of real networks
present multi-scale behavior with nodes structured in different types of
functional groups and communities. While the majority of approaches for
classification of nodes in a complex network has relied on local measurements
of the topology/connectivity around each node, valuable information about node
functionality can be obtained by Concentric (or Hierarchical) Measurements. In
this paper we explore the possibility of using a set of Concentric Measurements
and agglomerative clustering methods in order to obtain a set of functional
groups of nodes. Concentric clustering coefficient and convergence ratio are
chosen as segregation parameters for the analysis of a institutional
collaboration network including various known communities (departments of the
University of S\~ao Paulo). A dendogram is obtained and the results are
analyzed and discussed. Among the interesting obtained findings, we emphasize
the scale-free nature of the obtained network, as well as the identification of
different patterns of authorship emerging from different areas (e.g. human and
exact sciences). Another interesting result concerns the relatively uniform
distribution of hubs along the concentric levels, contrariwise to the
non-uniform pattern found in theoretical scale free networks such as the BA
model.Comment: 15 pages, 13 figure
Information Flow in Social Groups
We present a study of information flow that takes into account the
observation that an item relevant to one person is more likely to be of
interest to individuals in the same social circle than those outside of it.
This is due to the fact that the similarity of node attributes in social
networks decreases as a function of the graph distance. An epidemic model on a
scale-free network with this property has a finite threshold, implying that the
spread of information is limited. We tested our predictions by measuring the
spread of messages in an organization and also by numerical experiments that
take into consideration the organizational distance among individuals
Synchronization and modularity in complex networks
We investigate the connection between the dynamics of synchronization and the
modularity on complex networks. Simulating the Kuramoto's model in complex
networks we determine patterns of meta-stability and calculate the modularity
of the partition these patterns provide. The results indicate that the more
stable the patterns are, the larger tends to be the modularity of the partition
defined by them. This correlation works pretty well in homogeneous networks
(all nodes have similar connectivity) but fails when networks contain hubs,
mainly because the modularity is never improved where isolated nodes appear,
whereas in the synchronization process the characteristic of hubs is to have a
large stability when forming its own community.Comment: To appear in the Proceedings of Workshop on Complex Systems: New
Trends and Expectations, Santander, Spain, 5-9 June 200
Knowledge-based simulation
An architecture for a knowledge-based simulator is described. The task of scheduling represents an area in which such a tool might be applied. More specifically, scheduling for crew and ground support activities for the shuttle and space station would benefit from the application of knowledge-based simulation. The knowledge-based simulator would allow the crew and support personnel to schedule and reschedule activities in a timely and flexible manner in order to examine and test possible plans
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