51 research outputs found
Vulnerability of LTE to Hostile Interference
LTE is well on its way to becoming the primary cellular standard, due to its
performance and low cost. Over the next decade we will become dependent on LTE,
which is why we must ensure it is secure and available when we need it.
Unfortunately, like any wireless technology, disruption through radio jamming
is possible. This paper investigates the extent to which LTE is vulnerable to
intentional jamming, by analyzing the components of the LTE downlink and uplink
signals. The LTE physical layer consists of several physical channels and
signals, most of which are vital to the operation of the link. By taking into
account the density of these physical channels and signals with respect to the
entire frame, as well as the modulation and coding schemes involved, we come up
with a series of vulnerability metrics in the form of jammer to signal ratios.
The ``weakest links'' of the LTE signals are then identified, and used to
establish the overall vulnerability of LTE to hostile interference.Comment: 4 pages, see below for citation. M. Lichtman, J. Reed, M. Norton, T.
Clancy, "Vulnerability of LTE to Hostile Interference'', IEEE Global
Conference on Signal and Information Processing (GlobalSIP), Dec 201
Earth Observation GroundSystems in the Cloud
DEFINITION:
A pooled set of compute resources that can be centrally managed and dynamically provisioned to provide the required computation power or storage for a specific task
WHY USE IT: Enhanced compute resource management High data-rate applications requiring pooled compute resources Remote ground terminals that cannot support processing at the antenn
Corticosteroid-responsive Enteropathy of Infancy
Nineteen American infants aged less than three months developed
persistent diarrhoea, acidosis, hypoalbuminaemia, and malnutrition,
without evidence of enteric pathogens. Symptoms began 11-59 days before
admission to the University of North Carolina Children's Hospital, and
infants were fed semi-elemental formula. Despite further treatment with
amino acid-based formula by continuous nasogastric infusion, diarrhoea
persisted. Endoscopic biopsies showed inflammation in the stomach,
duodenum, and/or colon. A trial of intravenous corticosteroids was
initiated in 14 infants. Corticosteroids were associated with rapid
resolution of diarrhoea (duration after corticosteroids=3.8\ub11.7
days [mean+SD]). In contrast, five infants with identical history were
not treated with corticosteroids. In three infants, diarrhoea lasted
for 92-147 days versus 31\ub13 total days in the treated group. In
the other two infants, diarrhoea worsened after discharge, but were
treated later with corticosteroids, with rapid resolution.
Corticosteroids were uneventfully weaned over a four-month period. The
results suggest that a trial of corticosteroids in infants with
unresponsive persistent diarrhoea of unknown origin is beneficial and
deserves prospective evaluation
Bounded Expectations: Resource Analysis for Probabilistic Programs
This paper presents a new static analysis for deriving upper bounds on the
expected resource consumption of probabilistic programs. The analysis is fully
automatic and derives symbolic bounds that are multivariate polynomials of the
inputs. The new technique combines manual state-of-the-art reasoning techniques
for probabilistic programs with an effective method for automatic
resource-bound analysis of deterministic programs. It can be seen as both, an
extension of automatic amortized resource analysis (AARA) to probabilistic
programs and an automation of manual reasoning for probabilistic programs that
is based on weakest preconditions. As a result, bound inference can be reduced
to off-the-shelf LP solving in many cases and automatically-derived bounds can
be interactively extended with standard program logics if the automation fails.
Building on existing work, the soundness of the analysis is proved with respect
to an operational semantics that is based on Markov decision processes. The
effectiveness of the technique is demonstrated with a prototype implementation
that is used to automatically analyze 39 challenging probabilistic programs and
randomized algorithms. Experimental results indicate that the derived constant
factors in the bounds are very precise and even optimal for many programs
A Computational Framework for Ultrastructural Mapping of Neural Circuitry
Circuitry mapping of metazoan neural systems is difficult because canonical neural regions (regions containing one or more copies of all components) are large, regional borders are uncertain, neuronal diversity is high, and potential network topologies so numerous that only anatomical ground truth can resolve them. Complete mapping of a specific network requires synaptic resolution, canonical region coverage, and robust neuronal classification. Though transmission electron microscopy (TEM) remains the optimal tool for network mapping, the process of building large serial section TEM (ssTEM) image volumes is rendered difficult by the need to precisely mosaic distorted image tiles and register distorted mosaics. Moreover, most molecular neuronal class markers are poorly compatible with optimal TEM imaging. Our objective was to build a complete framework for ultrastructural circuitry mapping. This framework combines strong TEM-compliant small molecule profiling with automated image tile mosaicking, automated slice-to-slice image registration, and gigabyte-scale image browsing for volume annotation. Specifically we show how ultrathin molecular profiling datasets and their resultant classification maps can be embedded into ssTEM datasets and how scripted acquisition tools (SerialEM), mosaicking and registration (ir-tools), and large slice viewers (MosaicBuilder, Viking) can be used to manage terabyte-scale volumes. These methods enable large-scale connectivity analyses of new and legacy data. In well-posed tasks (e.g., complete network mapping in retina), terabyte-scale image volumes that previously would require decades of assembly can now be completed in months. Perhaps more importantly, the fusion of molecular profiling, image acquisition by SerialEM, ir-tools volume assembly, and data viewers/annotators also allow ssTEM to be used as a prospective tool for discovery in nonneural systems and a practical screening methodology for neurogenetics. Finally, this framework provides a mechanism for parallelization of ssTEM imaging, volume assembly, and data analysis across an international user base, enhancing the productivity of a large cohort of electron microscopists
Metastatic colorectal cancer outcomes by age among ARCAD first- and second-line Clinical trials
Background
We evaluated the time to progression (TTP) and survival outcomes of second-line therapy for metastatic colorectal cancer among adults aged 70 years and older compared with younger adults following progression on first-line clinical trials.
Methods
Associations between clinical and disease characteristics, time to initial progression, and rate of receipt of second-line therapy were evaluated. TTP and overall survival (OS) were compared between older and younger adults in first- and second-line trials by Cox regression, adjusting for age, sex, Eastern Cooperative Oncology Group Performance Status, number of metastatic sites and presence of metastasis in the lung, liver, or peritoneum. All statistical tests were 2-sided.
Results
Older adults comprised 16.4% of patients on first-line trials (870 total older adults aged >70 years; 4419 total younger adults aged ā¤70 years, on first-line trials). Older adults and those with Eastern Cooperative Oncology Group Performance Status >0 were less likely to receive second-line therapy than younger adults. Odds of receiving second-line therapy decreased by 11% for each additional decade of life in multivariable analysis (odds ratio = 1.11, 95% confidence interval = 1.02 to 1.21, P = .01). Older and younger adults enrolled in second-line trials experienced similar median TTP and median OS (median TTP = 5.1 vs 5.2 months, respectively; median OS = 11.6 vs 12.4 months, respectively).
Conclusions
Older adults were less likely to receive second-line therapy for metastatic colorectal cancer, though we did not observe a statistical difference in survival outcomes vs younger adults following second-line therapy. Further study should examine factors affecting decisions to treat older adults with second-line therapy. Inclusion of geriatric assessment may provide better criteria regarding the risks and benefits of second-line therapy
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