19,529 research outputs found

    The Singular Values of the GOE

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    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 χ\chi-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 GG-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?

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    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

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    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?

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    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.

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    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

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    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 π\pi-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

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    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

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    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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