1,344 research outputs found
Patterson v. Commonwealth: An Illustration of the Legal Complexity of DNA Databases
In the old-fashioned drawing-room murder mysteries, the villain usually eliminated his target in some Victorian manner - asphyxiation in bed with a pillow, drowning in a clawed-foot tub, stabbing in the back with a letter opener - and then skulked away, convinced he had committed the perfect crime. In the plot of these mysteries, the foil to the crime always proved to be the experienced detection of a meticulous sleuth. AgathaChristie would use the skills of Hercule Poirot or Miss Marple within the plot of her novels to detect the one flaw in the murderer\u27s technique. Perhaps there was some painfully obvious motive held by one of the guests at the summer home. Perhaps the villain\u27s mother embroidered the pillow used to asphyxiate the victim, or the letter opener was engraved with a unique identifying mark. Regardless of the simplicity or complexity of the villain\u27s methods, he was always caught. In these novels, there was no such thing as the perfect crime
Factorizing LambdaMART for cold start recommendations
Recommendation systems often rely on point-wise loss metrics such as the mean
squared error. However, in real recommendation settings only few items are
presented to a user. This observation has recently encouraged the use of
rank-based metrics. LambdaMART is the state-of-the-art algorithm in learning to
rank which relies on such a metric. Despite its success it does not have a
principled regularization mechanism relying in empirical approaches to control
model complexity leaving it thus prone to overfitting.
Motivated by the fact that very often the users' and items' descriptions as
well as the preference behavior can be well summarized by a small number of
hidden factors, we propose a novel algorithm, LambdaMART Matrix Factorization
(LambdaMART-MF), that learns a low rank latent representation of users and
items using gradient boosted trees. The algorithm factorizes lambdaMART by
defining relevance scores as the inner product of the learned representations
of the users and items. The low rank is essentially a model complexity
controller; on top of it we propose additional regularizers to constraint the
learned latent representations that reflect the user and item manifolds as
these are defined by their original feature based descriptors and the
preference behavior. Finally we also propose to use a weighted variant of NDCG
to reduce the penalty for similar items with large rating discrepancy.
We experiment on two very different recommendation datasets, meta-mining and
movies-users, and evaluate the performance of LambdaMART-MF, with and without
regularization, in the cold start setting as well as in the simpler matrix
completion setting. In both cases it outperforms in a significant manner
current state of the art algorithms
A Personalised Ranking Framework with Multiple Sampling Criteria for Venue Recommendation
Recommending a ranked list of interesting venues to users based on their preferences has become a key functionality in Location-Based Social Networks (LBSNs) such as Yelp and Gowalla. Bayesian Personalised Ranking (BPR) is a popular pairwise recommendation technique that is used to generate the ranked list of venues of interest to a user, by leveraging the user's implicit feedback such as their check-ins as instances of positive feedback, while randomly sampling other venues as negative instances. To alleviate the sparsity that affects the usefulness of recommendations by BPR for users with few check-ins, various approaches have been proposed in the literature to incorporate additional sources of information such as the social links between users, the textual content of comments, as well as the geographical location of the venues. However, such approaches can only readily leverage one source of additional information for negative sampling. Instead, we propose a novel Personalised Ranking Framework with Multiple sampling Criteria (PRFMC) that leverages both geographical influence and social correlation to enhance the effectiveness of BPR. In particular, we apply a multi-centre Gaussian model and a power-law distribution method, to capture geographical influence and social correlation when sampling negative venues, respectively. Finally, we conduct comprehensive experiments using three large-scale datasets from the Yelp, Gowalla and Brightkite LBSNs. The experimental results demonstrate the effectiveness of fusing both geographical influence and social correlation in our proposed PRFMC framework and its superiority in comparison to BPR-based and other similar ranking approaches. Indeed, our PRFMC approach attains a 37% improvement in MRR over a recently proposed approach that identifies negative venues only from social links
A Life Reclaimed: George Evans (1766-1857) of Norbury, Winster, Derby and Belper
George Evans, the elder brother of Robert Evans, George Eliot\u27s father, has generally been disparaged as a drunkard who died young, but the following account of further research into his life aims to set the record straight. What is known for certain is that he died on 28 October 1857 at his daughter\u27s house in Swinney Lane, Belper, Derbyshire, and was buried in the Churchyard of St Peter\u27s Parish Church at Belper. He was 90 years of age. On the death certificate his occupation is given as \u27A shoemaker at Derby (Master),
The immediate descendants of his daughter, Elizabeth, knew that there was a definite link between \u27their\u27 Evans and the Norbury Evans family and that Elizabeth was a first cousin of Mary Ann - although they were unable to piece together her exact background and history. It was fortunate that her father\u27s Bible, with pages giving birth and death entries from 1800 to 1857, passed down to her son, William Wheeldon, to his daughter Florence Annie and to her son Dr Douglas Woods (father of John Woods, a current member of the George Eliot Fellowship). These entries in George Evans\u27s Bible provided the crucial information needed to begin the current investigation.
The Wheeldons of Belper were proud of their connection with the great writer. Florence encouraged her three sons to read the Eliot novels \u27because she was familyâ, saying that when she herself was a child (in the late 1870s and 80s) there was always much talk at home about Mary Ann. The Wheeldons were acquainted with Herbert Spencer and Florence was pleased to tell her sons that \u27her father, William Wheeldon, had brought her from Belper to take tea with Herbert Spencer at his home in Derby\u27 .1 Herbert Spencer\u27s father was secretary to the Derby Philosophical Society - founded by Dr Erasmus Darwin of Derby and William Strutt2 - and William Wheeldon, a thinking as well as a practical man, had an interest in Darwinism and spiritualism. It would be surprising if his Evans ancestry were not also a topic of conversation
Anomalous Neutrino Reactions at HERA
We study the sensitivity of HERA to new physics using the helicity suppressed
reaction , where the final neutrino can be a standard
model one or a heavy neutrino. The approach is model independent and is based
on an effective lagrangian parametrization. It is shown that HERA will put
significant bounds on the scale of new physics, though, in general, these are
more modest than previously thought. If deviations from the standard model are
observed in the above processes, future colliders such as the SSC and LHC will
be able to directly probe the physics responsible for these discrepancies}Comment: 11 Pages + 2 figures is TOPDRAWER (included at the end or available
by mail). Report UCRHEP-T113 (requires the macropackage PHYZZX). A line in
the TeX file requesting an input file has been removed, it caused problem
Conformal Field Theory Correlators from Classical Scalar Field Theory on
We use the correspondence between scalar field theory on and a
conformal field theory on to calculate the 3- and 4-point functions of
the latter. The classical scalar field theory action is evaluated at tree
level.Comment: 9 pages, LaTeX2e with amsmath, amsfonts packages, section 2
rewritten, references adde
The effect of dance mat exergaming systems on physical activity and health â related outcomes in secondary schools: results from a natural experiment
Background: Exergaming has been proposed as an innovative method for physical activity promotion. However, large effectiveness studies are rare. In January 2011, dance mat systems were introduced in secondary schools in two districts in England with the aim of promoting an innovative opportunity for physical activity. The aim of this natural experiment was to examine the effect of introducing the dance mat exergaming systems on physical activity and health-related outcomes in 11â13 year old students using a non-randomised controlled design and mixed methods. Methods: Participants were recruited from five schools in intervention districts (nâ=â280) and two schools in neighbouring control districts (nâ=â217). Data on physical activity (accelerometer), anthropometrics (weight, BMI and percentage of body fat), aerobic fitness (20-m multistage shuttle run test), health-related quality of life (Kidscreen questionnaire), self-efficacy (childrenâs physical activity self-efficacy survey), school attendance, focus groups with children and interviews with teachers were collected at baseline and approximately 12 months follow-up. Results: There was a negative intervention effect on total physical activity (-65.4 cpm CI: -12.6 to -4.7), and light and sedentary physical activity when represented as a percentage of wear time (Light: -2.3% CI: -4.5 to 0.2; Sedentary: 3.3% CI: 0.7 to 5.9). However, compliance with accelerometers at follow-up was poor. There was a significant positive intervention effect on weight (-1.7 kg, 95% CI: -2.9 to -0.4), BMI (-0.9 kg/m2, 95% CI: -1.3 to -0.4) and percentage of body fat (-2.2%, 95% CI: -4.2 to -0.2). There was also evidence of improvement in some health-related quality of life parameters: psychological well-being (2.5, 95% CI: 0.1 to 4.8) and autonomy and parent relation (4.2, 95% CI: 1.4 to 7.0). Conclusions: The implementation of a dance mat exergaming scheme was associated with improvement in anthropometric measurements and parameters of health-related quality of life. However, the mechanisms of these benefits are unclear as there was insufficient data from physical activity to draw robust conclusions. Qualitative findings suggest that there was declining support for the initiative over time, meaning that potential benefits may not have been achieved
LEP1 vs. Future Colliders: Effective Operators And Extended Gauge Group
In an effective Lagrangian approach to physics beyond the Standard Model, it
has been argued that imposing invariance severely restricts
the discovery potential of future colliders. We exhibit a possible way out in
an extended gauge group context.Comment: 14 pages , CERN-TH.6573/92 ULB.TH.04/92 (phyzzx, 3 eps-figs incl.
Bounds on the electromagnetic interactions of excited spin-3/2 leptons
We discuss possible deviations from QED produced by a virtual excited
spin-3/2 lepton in the reaction . Data recorded
by the OPAL Collaboration at a c.m. energy are used to
establish bounds on the nonstandard-lepton mass and coupling strengths.Comment: Latex, 5 pages, 7 ps figures. To be published in Phys. Rev.
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