4,403 research outputs found
Characterizing Component Hiding Using Ancestral Entropy
In this research, the problem of software protection and the attributes that define that protection is considered. Specifically, how to protect programs defined as structural combinational logic gates. Obfuscation is one technique for protecting such circuits and involves replacing an original circuit with a functionally equivalent variant that has some definable hiding property. The difficulty of reverse engineering versus identifying and recovering the original components or sub-circuits within an original circuit is compared. With a polymorphic circuit engine that produces semantically equivalent variations of standard benchmark circuits the level of component hiding across variants with different physical configurations is determined to provide an entropy-based attribute to assess whether components are merged at the structural level. Specific types of obfuscating transformations with respect to component hiding using ancestral entropy are compared as well as the measure of uncertainty related to origination of a gate within a circuit
Maternal and fetal risk factors for stillbirth : population based study
Objective: To assess the main risk factors associated with stillbirth in a multiethnic English maternity population.
Design: Cohort study.
Setting: National Health Service region in England.
Population: 92 218 normally formed singletons including 389 stillbirths from 24 weeks of gestation, delivered during 2009-11.
Main outcome measure: Risk of stillbirth.
Results: Multivariable analysis identified a significant risk of stillbirth for parity (para 0 and para ≥3), ethnicity (African, African-Caribbean, Indian, and Pakistani), maternal obesity (body mass index ≥30), smoking, pre-existing diabetes, and history of mental health problems, antepartum haemorrhage, and fetal growth restriction (birth weight below 10th customised birthweight centile). As potentially modifiable risk factors, maternal obesity, smoking in pregnancy, and fetal growth restriction together accounted for 56.1% of the stillbirths. Presence of fetal growth restriction constituted the highest risk, and this applied to pregnancies where mothers did not smoke (adjusted relative risk 7.8, 95% confidence interval 6.6 to 10.9), did smoke (5.7, 3.6 to 10.9), and were exposed to passive smoke only (10.0, 6.6 to 15.8). Fetal growth restriction also had the largest population attributable risk for stillbirth and was fivefold greater if it was not detected antenatally than when it was (32.0% v 6.2%). In total, 195 of the 389 stillbirths in this cohort had fetal growth restriction, but in 160 (82%) it had not been detected antenatally. Antenatal recognition of fetal growth restriction resulted in delivery 10 days earlier than when it was not detected: median 270 (interquartile range 261-279) days v 280 (interquartile range 273-287) days. The overall stillbirth rate (per 1000 births) was 4.2, but only 2.4 in pregnancies without fetal growth restriction, increasing to 9.7 with antenatally detected fetal growth restriction and 19.8 when it was not detected.
Conclusion: Most normally formed singleton stillbirths are potentially avoidable. The single largest risk factor is unrecognised fetal growth restriction, and preventive strategies need to focus on improving antenatal detection
Pacific Ocean Forcing and Atmospheric Variability are the Dominant Causes of Spatially Widespread Droughts in the Contiguous United States
The contributions of oceanic and atmospheric variability to spatially widespread summer droughts in the contiguous United States (hereafter, pan-CONUS droughts) are investigated using 16-member ensembles of the Community Climate Model version 3 (CCM3) forced with observed sea surface temperatures (SSTs) from 1856 to 2012. The employed SST forcing fields are either (i) global or restricted to the (ii) tropical Pacific or (iii) tropical Atlantic to isolate the impacts of these two ocean regions on pan-CONUS droughts. Model results show that SST forcing of pan-CONUS droughts originates almost entirely from the tropical Pacific because of atmospheric highs from the northern Pacific to eastern North America established by La Nia conditions, with little contribution from the tropical Atlantic. Notably, in all three model configurations, internal atmospheric variability influences pan-CONUS drought occurrence by as much or more than the ocean forcing and can alone cause pan-CONUS droughts by establishing a dominant high centered over the US montane West. Similar results are found for the Community Atmosphere Model version 5 (CAM5). Model results are compared to the observational record, which supports model-inferred contributions to pan-CONUS droughts from La Nias and internal atmospheric variability. While there may be an additional association with warm Atlantic SSTs in the observational record, this association is ambiguous due to the limited number of observed pan-CONUS. The ambiguity thus opens the possibility that the observational results are limited by sampling over the 20th-century and not at odds with the suggested dominance of Pacific Ocean forcing in the model ensembles
A Proposal to Elucidate the Net Benefits of Digital Twins in Electrical Generation Facilities: An IS Success Perspective
The rapid integration of industrial Internet of things (IoT) technology has enabled widespread adoption of digital twin (DT) technologies. The work herein proposes to understand the net benefits of the DT technologies using the IS Success model. We propose to conduct interviews and surveys of DT users at industrial gas turbine electrical generation facilities to gain a better understanding of the costs and benefits of DTs in electricity generation. In doing so we will revise and the IS success model with the latest research on technology use and extend it to DT technologies
An Empirical Evaluation of Proposed Civil Rules for Multidistrict Litigation
The Civil Rules Committee of the Judicial Conference of theUnited States recently began considering the need for specificrules regarding multidistrict litigation (MDL) proceedings. Thepossibility of creating rules specifically for MDL originates withrecently proposed legislation prompted by groups typically tiedto the defense bar. One area the Civil Rules Committee isconsidering concerns the use of fact sheets in MDL proceedings.These party-negotiated questionnaires—directed at bothparties to the case—inform judges and attorneys about thescope of the proceeding. Understanding whether these casemanagement tools are currently being used and how they workwith other tools, such as bellwether trials, in MDL proceedingswill help inform a discussion of the need for specific MDL rules.Despite their importance, very little published, empirical worklooks at fact sheets in MDL proceedings. This is the firstcomprehensive study of the use of fact sheets.Using a sample of 116 mass tort proceedings—typicallyinvolving products liability—centralized through MDLbetween 2008 and 2018, we examine when fact sheets wereordered, what the procedures for complying with the casemanagement order were, what information was collected, andwhat effect fact sheets had on the termination of theproceedings. The proceedings ranged between 3 and 40,533actions and were open a minimum of 118 days and a maximumof 3811 days. Actions terminated within the proceeding at least
98% of the time, but little available information existsregarding how the actions terminated. These proceedings werecentralized in forty districts. We find that fact sheets wereordered more than half the time and were most likely to be usedin the largest proceedings. The information in fact sheets wasused in proceedings in several ways, including to identify casesfor bellwether trials and winnowing cases. Using fact sheets,moreover, led to quicker termination of the proceeding, all elsebeing equal. Our sample of proceedings suggests judges use factsheets to organize products liability proceedings when judgesperceive they are merited, after considering the size of theproceeding or the nature of the litigation. The frequency withwhich judges already employ fact sheets and the variation inuses call into question both the need for a rule and how to writeone without tying the hands of transferee judges. Many issuesregarding how fact sheets are used remain to be studied morein-depth. We encourage future studies regarding how factsheets are used across MDL proceedings
Wikidata and knowledge graphs in practice: using semantic SEO to create discoverable, accessible, machine-readable definitions of the people, places, and services in libraries and archives
Libraries expand the access and visibility of data and research in support of an informed public. Search engines have limited knowledge of the dynamic nature of libraries - their people, their services, and their resources. The very definition of libraries in online environments is outdated and misleading. This article offers a solution to this metadata problem by redefining libraries for Machine Learning environments and search engines. Two ways to approach this problem include implementing local structured data in a knowledge graph model and “inside-out” definitions in Semantic Web endpoints. MSU Library has found that implementing a “Knowledge Graph” linked data model leads to improved discovery and interpretation by the bots and search engines that index and describe what libraries are, what they do, and their scholarly content. In contrast, LSE Library has found that contributing to Wikidata, a collaborative and global metadata source, can increase understanding of libraries and extend their reach and engagement. This article demonstrates that Wikidata can be used to push out data, the technical details of knowledge graph markup, and the practice of semantic Search Engine Optimization (SEO). It explores how metadata can represent an organization equitably and how this improves the reach of global information communities
A Persistent Simulation Environment for Autonomous Systems
The age of Autonomous Unmanned Aircraft Systems (AUAS) is creating new challenges for the accreditation and certification requiring new standards, policies and procedures that sanction whether a UAS is safe to fly. Establishing a basis for certification of autonomous systems via research into trust and trustworthiness is the focus of Autonomy Teaming and TRAjectories for Complex Trusted Operational Reliability (ATTRACTOR), a new NASA Convergent Aeronautics Solution (CAS) project. Simulation Environments to test and evaluate AUAS decision making may be a low-cost solution to help certify that various AUAS systems are trustworthy enough to be allowed to fly in current general and commercial aviation airspace. NASA is working to build a peer-to-peer persistent simulation (P3 Sim) environment. The P3 Sim will be a Massively Multiplayer Online (MMO) environment were AUAS avatars can interact with a complex dynamic environment and each other. The focus of the effort is to provide AUAS researchers a low-cost intuitive testing environment that will aid training for and assessment of decisions made by autonomous systems such as AUAS. This presentation focuses on the design approach and challenges faced in development of the P3 Sim Environment is support of investigating trustworthiness of autonomous systems
Clustering Hyperspectral Imagery for Improved Adaptive Matched Filter Performance
This paper offers improvements to adaptive matched filter (AMF) performance by addressing correlation and non-homogeneity problems inherent to hyperspectral imagery (HSI). The estimation of the mean vector and covariance matrix of the background should be calculated using “target-free” data. This statement reflects the difficulty that including target data in estimates of the mean vector and covariance matrix of the background could entail. This data could act as statistical outliers and severely contaminate the estimators. This fact serves as the impetus for a 2-stage process: First, attempt to remove the target data from the background by way of the employment of anomaly detectors. Next, with remaining data being relatively “target-free” the way is cleared for signature matching. Relative to the first stage, we were able to test seven different anomaly detectors, some of which are designed specifically to deal with the spatial correlation of HSI data and/or the presence of anomalous pixels in local or global mean and covariance estimators. Relative to the second stage, we investigated the use of cluster analytic methods to boost AMF performance. The research shows that accounting for spatial correlation effects in the detector yields nearly “target-free” data for use in an AMF that is greatly benefitted through the use of cluster analysis methods
An early Portuguese mariner's astrolabe from the Sodré Wreck‐site, Al Hallaniyah, Oman
A unique leaded‐gunmetal disc decorated with iconic Portuguese markings was recovered in 2014 during archaeological excavations at the Sodré shipwreck site in Al Hallaniyah, Oman. Initially the identity and function of the disc was unknown, although it did possess characteristics suggesting it could be an astrolabe. Laser imaging of the disc post conservation revealed regular scale marks on the limb of its upper right quadrant. Accurate digital measurements of the marks show them to be graded at close to 5‐degree intervals, thus confirming the identity of the disc as a mariner's astrolabe and the earliest known example discovered to date
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