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On the effectiveness of run-time checks
Run-time checks are often assumed to be a cost-effective way of improving the dependability of software components, by checking required properties of their outputs and flagging an output as incorrect if it fails the check. However, evaluating how effective they are going to be in a future application is difficult, since the effectiveness of a check depends on the unknown faults of the program to which it is applied. A programming contest, providing thousands of programs written to the same specifications, gives us the opportunity to systematically test run-time checks to observe statistics of their effects on actual programs. In these examples, run-time checks turn out to be most effective for unreliable programs. For more reliable programs, the benefit is relatively low as compared to the gain that can be achieved by other (more expensive) measures, most notably multiple-version diversity
Towards flavour diffusion coefficient and electrical conductivity without ultraviolet contamination
By subtracting from a recent lattice measurement of the thermal
vector-current correlator the known 5-loop vacuum contribution, we demonstrate
that the remainder is small and shows no visible short-distance divergence. It
can therefore in principle be subjected to model-independent analytic
continuation. Testing a particular implementation, we obtain estimates for the
flavour-diffusion coefficient (2 pi T D \gsim 0.8) and electrical conductivity
which are significantly smaller than previous results. Although systematic
errors remain beyond control at present, some aspects of our approach could be
of a wider applicability.Comment: 7 pages. v2: clarifications added, published versio
Optimal Hypercontractivity for Fermi Fields and Related Non-Commutative Integration
Optimal hypercontractivity bounds for the fermion oscillator semigroup are
obtained. These are the fermion analogs of the optimal hypercontractivity
bounds for the boson oscillator semigroup obtained by Nelson. In the process,
several results of independent interest in the theory of non-commutative
integration are established. {}.Comment: 18 p., princeton/ecel/7-12-9
Search for Charge Symmetry Violation in n-p Scattering
This work was supported by National Science Foundation Grants PHY 76-84033A01, PHY 78-22774, and Indiana Universit
The Basics of Water Waves Theory for Analogue Gravity
This chapter gives an introduction to the connection between the physics of
water waves and analogue gravity. Only a basic knowledge of fluid mechanics is
assumed as a prerequisite.Comment: 36 pages. Lecture Notes for the IX SIGRAV School on "Analogue
Gravity", Como (Italy), May 201
Beyond the tip of the seamount: Distinct megabenthic communities found beyond the charismatic summit sponge ground on an arctic seamount (Schulz Bank, Arctic Mid-Ocean Ridge)
Our understanding of the benthic communities on arctic seamounts and descriptions of such communities in habitat classification systems are limited. In recent years, Schulz Bank (73°52′N 7°30′E), a seamount on the Arctic Mid-Ocean Ridge (AMOR), has become well studied but the work has primarily focused on an arctic sponge ground at the summit. This has compounded a general assumption that the most biologically interesting community is on the summit alone. With the potential threat of deep-sea mining on nearby sites on AMOR, it is crucial to form a baseline understanding of the benthic megafaunal communities not only on the summit, but on the slopes and base of the seamount as well. Using video footage collected by a remotely operated vehicle in 2017 and 2018 to survey the seamount from 2700 to 580 m depth, several distinct megafauna communities on Schulz Bank were identified. Specifically, five biotopes, two of which were dominated by large structure-forming sponges, appeared to follow a depth gradient and change with the type of substrata present. The sponge-dominated communities on the summit and lower slope had the highest average community densities and number of morphotaxa per image compared to the upper slope and seamount base communities. Most notably, sponge-dominated bedrock walls on the lower slopes challenge the assumption that the summit is the most dense and diverse community on Schulz Bank. The results from this study lay the foundation for future research and conservation efforts of arctic sponge grounds by looking beyond the seamount summit to bring a full view of enigmatic sponge dominated ecosystems
On the equivalence between hierarchical segmentations and ultrametric watersheds
We study hierarchical segmentation in the framework of edge-weighted graphs.
We define ultrametric watersheds as topological watersheds null on the minima.
We prove that there exists a bijection between the set of ultrametric
watersheds and the set of hierarchical segmentations. We end this paper by
showing how to use the proposed framework in practice in the example of
constrained connectivity; in particular it allows to compute such a hierarchy
following a classical watershed-based morphological scheme, which provides an
efficient algorithm to compute the whole hierarchy.Comment: 19 pages, double-colum
Machine Learning Logistic Regression Model for Early Decision Making in Referral of Children with Cervical Lymphadenopathy Suspected of Lymphoma
While cervical lymphadenopathy is common in children, a decision model for detecting high-grade lymphoma is lacking. Previously reported individual lymphoma-predicting factors and multivariate models were not sufficiently discriminative for clinical application. To develop a diagnostic scoring tool, we collected data from all children with cervical lymphadenopathy referred to our national pediatric oncology center within 30 months (n = 182). Thirty-nine putative lymphoma-predictive factors were investigated. The outcome groups were classical Hodgkin lymphoma (cHL), nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL), non-Hodgkin lymphoma (NHL), other malignancies, and a benign group. We integrated the best univariate predicting factors into a multivariate, machine learning model. Logistic regression allocated each variable a weighing factor. The model was tested in a different patient cohort (n = 60). We report a 12-factor diagnostic model with a sensitivity of 95% (95% CI 89–98%) and a specificity of 88% (95% CI 77–94%) for detecting cHL and NHL. Our 12-factor diagnostic scoring model is highly sensitive and specific in detecting high-grade lymphomas in children with cervical lymphadenopathy. It may enable fast referral to a pediatric oncologist in patients with high-grade lymphoma and may reduce the number of referrals and unnecessary invasive procedures in children with benign lymphadenopathy.</p
On the application of radio frequency voltages to ion traps via helical resonators
Ions confined using a Paul trap require a stable, high voltage and low noise
radio frequency (RF) potential. We present a guide for the design and
construction of a helical coil resonator for a desired frequency that maximises
the quality factor for a set of experimental constraints. We provide an
in-depth analysis of the system formed from a shielded helical coil and an ion
trap by treating the system as a lumped element model. This allows us to
predict the resonant frequency and quality factor in terms of the physical
parameters of the resonator and the properties of the ion trap. We also compare
theoretical predictions with experimental data for different resonators, and
predict the voltage applied to the ion trap as a function of the Q-factor,
input power and the properties of the resonant circuit
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