8,525 research outputs found
Scalable Privacy-Preserving Data Sharing Methodology for Genome-Wide Association Studies
The protection of privacy of individual-level information in genome-wide
association study (GWAS) databases has been a major concern of researchers
following the publication of "an attack" on GWAS data by Homer et al. (2008)
Traditional statistical methods for confidentiality and privacy protection of
statistical databases do not scale well to deal with GWAS data, especially in
terms of guarantees regarding protection from linkage to external information.
The more recent concept of differential privacy, introduced by the
cryptographic community, is an approach that provides a rigorous definition of
privacy with meaningful privacy guarantees in the presence of arbitrary
external information, although the guarantees may come at a serious price in
terms of data utility. Building on such notions, Uhler et al. (2013) proposed
new methods to release aggregate GWAS data without compromising an individual's
privacy. We extend the methods developed in Uhler et al. (2013) for releasing
differentially-private -statistics by allowing for arbitrary number of
cases and controls, and for releasing differentially-private allelic test
statistics. We also provide a new interpretation by assuming the controls' data
are known, which is a realistic assumption because some GWAS use publicly
available data as controls. We assess the performance of the proposed methods
through a risk-utility analysis on a real data set consisting of DNA samples
collected by the Wellcome Trust Case Control Consortium and compare the methods
with the differentially-private release mechanism proposed by Johnson and
Shmatikov (2013).Comment: 28 pages, 2 figures, source code available upon reques
Assessing the Consumer Acceptance and Market Potential of Alternative Meats
Introduction, project objectives and project background: This initiative to this project, including the original project proposal, goes back to Professor Kevin Chen (he is no longer with the Department of Rural Economy). The project was initially scheduled to begin on 2004/05/01. When I took over this project and started to work as Principal Investigator on January 1, 2005, the following objectives were to be fulfilled (taken from Professor Kevin Chen's initial proposal): 1) Documentation of consumer awareness, attitude, and choice regarding alternative meats "At what level and to what extent are consumers aware of alternative meats?" What is consumer interest level in alternative meats and their willingness to change consumption behavior (i.e. how much are they willing to pay for alternative meats)? "What kinds of alternative meats are consumers eating?" What kinds of alternative meats are consumers most likely to try in the future? "Where are consumers buying and eating alternative meats (meat specialty store, direct market, supermarket, restaurant, and others)?" What attributes do consumers find desirable in alternative meats (leanness, nutrition, adventure, taste, and others)?" What are the main barriers affecting purchase of alternative meats (price, awareness of availability, exotic nature, cooking instructions, nutrition labeling, and others)? 2) Compilation of a consumer profile related to purchase of alternative meats "How do various socioeconomic and demographic factors affect consumer awareness, attitude, and acceptance of alternative meats?" What are the distinct consumer market segments that Alberta's alternative livestock and meat producers might target? 3) Development of marketing strategies and implications for the Alberta alternative livestock industry "What are the implications of the findings in 1) and 2) for developing effective advertising and promotion strategies to support the further development of Alberta's alternative livestock industry?"What are the implications of the finding in 1) and 2) for producing alternative meat products that are consumer friendly? "What are the implications of the findings in 1) and 2) for selecting the main marketing and distribution channels for alternative meat products? 1 A decision was made together with the DLFOA to focus our research efforts on three species: bison, elk and lamb. The overall purpose of our research was to improve the understanding of consumer perceptions towards the consumption of alternative meats, notably the above three species. More specifically, the objectives were to: 1) Document the attitude and purchasing choices for three alternative meats which are strategically important to Alberta's alternative livestock industry. 2) Analyze the effects of socio-economic factors of Alberta consumers in purchasing the above alternative meats. 3) Explore possibilities for market segmentation and marketing implications, also for other alternative meats (other than bison, elk and lamb). In order to achieve these objectives, this study has taken the following steps: 1) A preliminary survey was developed and received feedback from Professor Robert Hudson, University of Alberta. 2) This preliminary survey was revised by using four focus groups with Alberta consumers. 3) Three separate web-based surveys were constructed for bison, elk and lamb. In each of these surveys, a switching model was developed that employs revealed preference data in stated preference experiments. As consumers indicate their (un)willingness to switch away from beef, towards alternative meats, we addressed many issues; among them were: How important are which information sources in the purchasing decisions of alternative meats? 2 What role does farm origin traceability play in consumers' choice? To what extent do consumers care about Genetically Modified Organisms (GMO) in producing those meats?Food Consumption/Nutrition/Food Safety,
Tunable Quantum Fluctuation-Controlled Coherent Spin Dynamics
Temporal evolution of a macroscopic condensate of ultra cold atoms is usually
driven by mean field potentials, either due to scattering between atoms or due
to coupling to external fields; and coherent quantum dynamics have been
observed in various cold-atom experiments. In this article, we report results
of studies of a class of quantum spin dynamics which are purely driven by zero
point quantum fluctuations of spin collective coordinates. Unlike the usual
mean-field coherent dynamics, quantum fluctuation-controlled spin dynamics or
QFCSD studied here are very sensitive to variation of quantum fluctuations and
can be tuned by four to five order of magnitude using optical lattices. They
have unique dependence on optical lattice potential depths and quadratic Zeeman
fields. QFCSD can be potentially used to calibrate quantum fluctuations and
investigate correlated fluctuations and various universal scaling properties
near quantum critical points.Comment: 14 pages, 12 figures included; including detailed discussions on
thermal effects, trapping potentials and spin exchange losses. (To appear in
PRA
Quantum fluctuation-induced uniaxial and biaxial spin nematics
It is shown that zero point quantum fluctuations (ZPQFs) completely lift the
accidental continuous degeneracy that is found in mean field analysis of
quantum spin nematic phases of hyperfine spin 2 cold atoms. The result is two
distinct ground states which have higher symmetries: a uniaxial spin nematic
and a biaxial spin nematic with dihedral symmetry . There is a novel
first order quantum phase transition between the two phases as atomic
scattering lengths are varied. We find that the ground state of atoms
should be a uniaxial spin nematic. We note that the energy barrier between the
phases could be observable in dynamical experiments.Comment: 4 pages, 2 figures included; published versio
BRST Structures and Symplectic Geometry on a Class of Supermanifolds
By investigating the symplectic geometry and geometric quantization on a
class of supermanifolds, we exhibit BRST structures for a certain kind of
algebras. We discuss the undeformed and q-deformed cases in the classical as
well as in the quantum cases.Comment: 14 pages, Late
Machine Learning and Irresponsible Inference: Morally Assessing the Training Data for Image Recognition Systems
Just as humans can draw conclusions responsibly or irresponsibly, so too can computers. Machine learning systems that have been trained on data sets that include irresponsible judgments are likely to yield irresponsible predictions as outputs. In this paper I focus on a particular kind of inference a computer system might make: identification of the intentions with which a person acted on the basis of photographic evidence. Such inferences are liable to be morally objectionable, because of a way in which they are presumptuous. After elaborating this moral concern, I explore the possibility that carefully procuring the training data for image recognition systems could ensure that the systems avoid the problem. The lesson of this paper extends beyond just the particular case of image recognition systems and the challenge of responsibly identifying a personâs intentions. Reflection on this particular case demonstrates the importance (as well as the difficulty) of evaluating machine learning systems and their training data from the standpoint of moral considerations that are not encompassed by ordinary assessments of predictive accuracy
Neutrino Constraints on Inelastic Dark Matter after CDMS II
We discuss the neutrino constraints from solar and terrestrial dark matter
(DM) annihilations in the inelastic dark matter (iDM) scenario after the recent
CDMS II results. To reconcile the DAMA/LIBRA data with constraints from all
other direct experiments, the iDM needs to be light ( GeV) and
have a large DM-nucleon cross section ( 10 pb in the
spin-independent (SI) scattering and 10 pb in the
spin-dependent (SD) scattering). The dominant contribution to the iDM capture
in the Sun is from scattering off Fe/Al in the SI/SD case. Current bounds from
Super-Kamiokande exclude the hard DM annihilation channels, such as ,
, and . For soft channels such as and
, the limits are loose, but could be tested or further constrained
by future IceCube plus DeepCore. For neutrino constraints from the DM
annihilation in the Earth, due to the weaker gravitational effect of the Earth
and inelastic capture condition, the constraint exists only for small mass
splitting 40 keV and GeV even in the channel.Comment: 11 pages, 8 figure
Grid-Brick Event Processing Framework in GEPS
Experiments like ATLAS at LHC involve a scale of computing and data
management that greatly exceeds the capability of existing systems, making it
necessary to resort to Grid-based Parallel Event Processing Systems (GEPS).
Traditional Grid systems concentrate the data in central data servers which
have to be accessed by many nodes each time an analysis or processing job
starts. These systems require very powerful central data servers and make
little use of the distributed disk space that is available in commodity
computers. The Grid-Brick system, which is described in this paper, follows a
different approach. The data storage is split among all grid nodes having each
one a piece of the whole information. Users submit queries and the system will
distribute the tasks through all the nodes and retrieve the result, merging
them together in the Job Submit Server. The main advantage of using this system
is the huge scalability it provides, while its biggest disadvantage appears in
the case of failure of one of the nodes. A workaround for this problem involves
data replication or backup.Comment: 6 pages; document for CHEP'03 conferenc
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