4,523 research outputs found
The Christian Academic Librarian in the Technological Society
Full text linkIn our contemporary society, technologies establish the course of our lives. Libraries have always engaged various technologies to bring order to disorder and over the last two decades, academic libraries have undergone significant technological change. Librarians have sought to convey an orderliness to the visible world and humanityâs body of knowledge. How this technology and body of knowledge is engaged bears significance. The engagement of the Christian academic librarian should include a distinctly Christian perspective. This paper examines the engagement of the Christian academic librarian in the technological society
Exploring the Impact of Password Dataset Distribution on Guessing
Full text linkLeaks from password datasets are a regular occurrence. An organization may
defend a leak with reassurances that just a small subset of passwords were
taken. In this paper we show that the leak of a relatively small number of
text-based passwords from an organizations' stored dataset can lead to a
further large collection of users being compromised. Taking a sample of
passwords from a given dataset of passwords we exploit the knowledge we gain of
the distribution to guess other samples from the same dataset. We show
theoretically and empirically that the distribution of passwords in the sample
follows the same distribution as the passwords in the whole dataset. We propose
a function that measures the ability of one distribution to estimate another.
Leveraging this we show that a sample of passwords leaked from a given dataset,
will compromise the remaining passwords in that dataset better than a sample
leaked from another source
On Efficiency and Validity of Previous Homeplug MAC Performance Analysis
Get PDFThe Medium Access Control protocol of Power Line Communication networks
(defined in Homeplug and IEEE 1901 standards) has received relatively modest
attention from the research community. As a consequence, there is only one
analytic model that complies with the standardised MAC procedures and considers
unsaturated conditions. We identify two important limitations of the existing
analytic model: high computational expense and predicted results just prior to
the predicted saturation point do not correspond to long-term network
performance. In this work, we present a simplification of the previously
defined analytic model of Homeplug MAC able to substantially reduce its
complexity and demonstrate that the previous performance results just before
predicted saturation correspond to a transitory phase. We determine that the
causes of previous misprediction are common analytical assumptions and the
potential occurrence of a transitory phase, that we show to be of extremely
long duration under certain circumstances. We also provide techniques, both
analytical and experimental, to correctly predict long-term behaviour and
analyse the effect of specific Homeplug/IEEE 1901 features on the magnitude of
misprediction errors
Modeling, Analysis and Impact of a Long Transitory Phase in Random Access Protocols
Get PDFIn random access protocols, the service rate depends on the number of
stations with a packet buffered for transmission. We demonstrate via numerical
analysis that this state-dependent rate along with the consideration of Poisson
traffic and infinite (or large enough to be considered infinite) buffer size
may cause a high-throughput and extremely long (in the order of hours)
transitory phase when traffic arrivals are right above the stability limit. We
also perform an experimental evaluation to provide further insight into the
characterisation of this transitory phase of the network by analysing
statistical properties of its duration. The identification of the presence as
well as the characterisation of this behaviour is crucial to avoid
misprediction, which has a significant potential impact on network performance
and optimisation. Furthermore, we discuss practical implications of this
finding and propose a distributed and low-complexity mechanism to keep the
network operating in the high-throughput phase.Comment: 13 pages, 10 figures, Submitted to IEEE/ACM Transactions on
Networkin
Investigating the Distribution of Password Choices
Get PDFIn this paper we will look at the distribution with which passwords are
chosen. Zipf's Law is commonly observed in lists of chosen words. Using
password lists from four different on-line sources, we will investigate if
Zipf's law is a good candidate for describing the frequency with which
passwords are chosen. We look at a number of standard statistics, used to
measure the security of password distributions, and see if modelling the data
using Zipf's Law produces good estimates of these statistics. We then look at
the the similarity of the password distributions from each of our sources,
using guessing as a metric. This shows that these distributions provide
effective tools for cracking passwords. Finally, we will show how to shape the
distribution of passwords in use, by occasionally asking users to choose a
different password
Buffer Sizing for 802.11 Based Networks
Get PDFWe consider the sizing of network buffers in 802.11 based networks. Wireless
networks face a number of fundamental issues that do not arise in wired
networks. We demonstrate that the use of fixed size buffers in 802.11 networks
inevitably leads to either undesirable channel under-utilization or unnecessary
high delays. We present two novel dynamic buffer sizing algorithms that achieve
high throughput while maintaining low delay across a wide range of network
conditions. Experimental measurements demonstrate the utility of the proposed
algorithms in a production WLAN and a lab testbed.Comment: 14 pages, to appear on IEEE/ACM Transactions on Networkin
Economic Agendas in Civil Wars: What We Know, What We Need to Know
Get PDFcivil war, conflict prevention, human security
Innate Immunity in the immunopathogenesis of chronic viral infection
Get PDFNatural killer (NK) cells have a key role in control and clearance of viral infections. To carry
out this function NK cells are capable of recognising infected cells and responding with
induction of apoptosis in these cells, and production of pro-inflammatory cytokines. Target
cells are recognised through various stress or infection related activating signals alongside
âmissing selfâ recognition of down-regulation of human leukocyte antigen molecules.
Additional stimulation for NK cells comes in the form of the type I interferon (IFN), IFN-α,
which is released by infected cells and the immune systemâs sentinels, the dendritic cells (DC).
As well as stimulating NK cells, IFN-α induces an anti-viral state in cells through upregulation
of expression of IFN-stimulated genes.
Infections with hepatitis B, C, and ÎŽ viruses (HBV, HCV, HDV) cause viral hepatitis and are
major risk factors for developing liver fibrosis. Despite these infections causing similar clinical
manifestations, and until recently treatment for all three utilising IFN-α, these three viruses
differ greatly. Human immunodeficiency virus (HIV) is the causative agent of acquired
immune deficiency syndrome (AIDS). This disease is characterised by loss of CD4 expressing
cells resulting in a diminished immune system that leaves the host susceptible to
opportunistic infections. HIV-1 is the cause of the AIDS pandemic, while HIV-2 associates
with a slower disease progression.
Each of these viruses is able to cause chronic infection. Part of the pathology of chronic
infection, particularly HIV infection, is persistent immune activation and microbial
translocation. In attempting to clear the infection the immune system can become perpetually
activated, a condition associated with immune dysfunction. During this phase the immune
response can contribute to disease progression through off-target effects, or appear as
exhausted and dysfunctional.
In this thesis I will show that the phenotype and function of NK cells are altered during
infection, primarily dependent upon the stage of hepatitis infection irrespective of infecting
virus. For HIV infections NK cell activation is dependent upon the level of viral replication.
During IFN-α therapy for hepatitis infections there is an increase of the chronic inflammation
and microbial translocation marker sCD14, while NK cell function is altered due to
fluctuations in intracellular STAT signalling
Observations of IPv6 Addresses
Get PDFIPv6 addresses are longer than IPv4 addresses, and are so capable of greater expression. Given an IPv6 address, conventions and standards allow us to draw conclusions about how IPv6 is being used on the node with that address.
We show a technique for analysing IPv6 addresses and apply it to a number of datasets. The datasets include addresses seen at a busy mirror server, at an IPv6-enabled TLD DNS server and when running traceroute across the production IPv6 network. The technique quantifies differences in these datasets that we intuitively expect, and shows that IPv6 is being used in different ways by different groups
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