19,529 research outputs found
The Singular Values of the GOE
As a unifying framework for examining several properties that nominally
involve eigenvalues, we present a particular structure of the singular values
of the Gaussian orthogonal ensemble (GOE): the even-location singular values
are distributed as the positive eigenvalues of a Gaussian ensemble with chiral
unitary symmetry (anti-GUE), while the odd-location singular values,
conditioned on the even-location ones, can be algebraically transformed into a
set of independent -distributed random variables. We discuss three
applications of this structure: first, there is a pair of bidiagonal square
matrices, whose singular values are jointly distributed as the even- and
odd-location ones of the GOE; second, the magnitude of the determinant of the
GOE is distributed as a product of simple independent random variables; third,
on symmetric intervals, the gap probabilities of the GOE can be expressed in
terms of the Laguerre unitary ensemble (LUE). We work specifically with
matrices of finite order, but by passing to a large matrix limit, we also
obtain new insight into asymptotic properties such as the central limit theorem
of the determinant or the gap probabilities in the bulk-scaling limit. The
analysis in this paper avoids much of the technical machinery (e.g. Pfaffians,
skew-orthogonal polynomials, martingales, Meijer -function, etc.) that was
previously used to analyze some of the applications.Comment: Introduction extended, typos corrected, reference added. 31 pages, 1
figur
What happens when interviewers ask repeated questions in forensic interviews with children alleging abuse?
This study was designed to explore 1) the ways in which interviewers refocus alleged victims of abuse on their previous responses and 2) how children responded when they were refocused on their previous responses. Transcripts of 37 forensic interviews conducted by British police officers trained using the best practices spelled out in the Memorandum of Good Practice were examined. The instances in which interviewers asked repeated questions were isolated and coded into categories with respect to the reasons why interviewers needed to ask the repeated question (i.e., there was no apparent reason, to challenge a child’s response, clarification, no answer the first time the question was asked, digression, or compound question). The children’s responses to the repeated questions were further categorised into mutually exclusive categories (i.e., elaboration, repetition, contradiction, or no answer). On average interviewers asked children 8 repeated questions per interview. Most of the time interviewers asked repeated questions to challenge a previous response (62%), but they were also sometimes asked for no apparent reason (20%). Children repeated previous responses or elaborated on a previous response 81% of the time and contradicted themselves 7% of the time when re-asked the same question. We conclude that children did not appear unduly pressured to change their answers, and, more importantly, did not contradict themselves when interviewers attempted to refocus them on particular responses
Power adjustment and scheduling in OFDMA femtocell networks
Densely-deployed femtocell networks are used to enhance wireless coverage in public spaces like office buildings, subways, and academic buildings. These networks can increase throughput for users, but edge users can suffer from co-channel interference, leading to service outages. This paper introduces a distributed algorithm for network configuration, called Radius Reduction and Scheduling (RRS), to improve the performance and fairness of the network. RRS determines cell sizes using a Voronoi-Laguerre framework, then schedules users using a scheduling algorithm that includes vacancy requests to increase fairness in dense femtocell networks. We prove that our algorithm always terminate in a finite time, producing a configuration that guarantees user or area coverage. Simulation results show a decrease in outage probability of up to 50%, as well as an increase in Jain's fairness index of almost 200%
The New Directive on the Right of Citizens of the Union and their Family Members to Move and Reside Freely within the Territory of the Member States - What Changes Does it Bring?
Wohnstandort, EU-Recht, Niederlassungsrecht, Freizügigkeit, Europäische Wirtschafts- und Währungsunion, Residential location, Community law, Freedom of establishment, Freedom of movement, European Economic and Monetary Union
Forensic interviews with children in Scotland: a survey of interview practices among police.
The present study surveyed 91 police interviewers in Scottish police forces about their perceptions of how well they adhered to the Scottish Executive (2003) guidelines. Almost all respondents (97%) received the appropriate national training and overwhelmingly indicated (again 97%) that their training equipped them either quite, very, or extremely well for conducting their interviews. Not surprisingly, therefore, that most interviewers (88%) believed that their interviews allowed them to obtain full and complete accounts of the events being investigated. However, aside from this positive self evaluation there are reasons to be concerned about some aspects of the interviews being conducted; 1) Most interviewers (78%) received no refresher training, 2) no interviewers received formal feedback about the quality of interviews that they conducted, 3) practice interviews were reportedly not included in most interviews, 4) the use of open-ended prompts were not widely used with 20% of interviewers indicating that they were rarely used, and 5) interviews are not currently being electronically recorded. These results are discussed with respect to the context of child interviewing in Scotland and recommendations for future training
Electronic Instabilities of the AA-Honeycomb Bilayer
We use a functional renormalization group approach to study the instabilities
due to electron-electron interactions in a bilayer honeycomb lattice model with
AA stacking, as it might be relevant for layered graphene with this structure.
Starting with a tight- binding description for the four -bands, we
integrate out the modes of the dispersion by successively lowering an infrared
cutoff and determine the leading tendencies in the effective interactions. The
antiferromagnetic spin-density wave is an expected instability for dominant
local repulsion among the electrons, but for nonlocal interaction terms also
other instabilities occur. We discuss the phase diagrams depending on the model
parameters. We compare our results to single-layer graphene and the more common
AB-stacked bilayer, both qualitatively and quantitatively.Comment: 9 pages, 3 figures, Annalen der Physik, online available (2014
AMPHIBIAN RESPONSE TO A LARGE-SCALE HABITAT RESTORATION IN THE PRAIRIE POTHOLE REGION
Over the next half-century, scientists anticipate that nearly one third of the currently recognized 7,450 amphibian species will become extinct. Many organizations have responded to the challenge of conserving amphibian biodiversity, some indirectly. Under the auspices of the Iowa Great Lakes Management Plan, the United States Fish and Wildlife Service, Department of Natural Resources, and their partners have been implementing habitat restoration efforts designed to protect water quality, provide recreational opportunities, and benefit wildlife at the regional level. With this program, over 130 wetlands have been created in the past 30 years on recently purchased public lands—one of the largest wetland restoration projects conducted in the Prairie Pothole Region of the Great Plains. While amphibians were not the main target of these restorations, we show that in response, 121 new breeding populations of native Northern Leopard Frogs (Lithobates pipiens; n = 80) and Eastern Tiger Salamanders (Ambystoma tigrinum; n = 41) have been established; in addition, we found 19 populations of non-native American Bullfrogs (L. catesbeianus). Using the program PRESENCE, we show that leopard frog occupancy was greatest in newer (<18 years old), intermediate-sized wetlands, and that tiger salamander occupancy was greatest in small wetlands without fish and larval bullfrogs. These data imply that because native amphibians responded positively to these newly established wetlands, habitat availability has likely been a factor in limiting population numbers. Further, these data suggest the presence of fishes and introduced bullfrogs interferes with the ability of tiger salamanders to colonize restored wetlands
Indexing the Event Calculus with Kd-trees to Monitor Diabetes
Personal Health Systems (PHS) are mobile solutions tailored to monitoring
patients affected by chronic non communicable diseases. A patient affected by a
chronic disease can generate large amounts of events. Type 1 Diabetic patients
generate several glucose events per day, ranging from at least 6 events per day
(under normal monitoring) to 288 per day when wearing a continuous glucose
monitor (CGM) that samples the blood every 5 minutes for several days. This is
a large number of events to monitor for medical doctors, in particular when
considering that they may have to take decisions concerning adjusting the
treatment, which may impact the life of the patients for a long time. Given the
need to analyse such a large stream of data, doctors need a simple approach
towards physiological time series that allows them to promptly transfer their
knowledge into queries to identify interesting patterns in the data. Achieving
this with current technology is not an easy task, as on one hand it cannot be
expected that medical doctors have the technical knowledge to query databases
and on the other hand these time series include thousands of events, which
requires to re-think the way data is indexed. In order to tackle the knowledge
representation and efficiency problem, this contribution presents the kd-tree
cached event calculus (\ceckd) an event calculus extension for knowledge
engineering of temporal rules capable to handle many thousands events produced
by a diabetic patient. \ceckd\ is built as a support to a graphical interface
to represent monitoring rules for diabetes type 1. In addition, the paper
evaluates the \ceckd\ with respect to the cached event calculus (CEC) to show
how indexing events using kd-trees improves scalability with respect to the
current state of the art.Comment: 24 pages, preliminary results calculated on an implementation of
CECKD, precursor to Journal paper being submitted in 2017, with further
indexing and results possibilities, put here for reference and chronological
purposes to remember how the idea evolve
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