18,651 research outputs found

    Kernel-based aggregation of marker-level genetic association tests involving copy-number variation

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    Genetic association tests involving copy-number variants (CNVs) are complicated by the fact that CNVs span multiple markers at which measurements are taken. The power of an association test at a single marker is typically low, and it is desirable to pool information across the markers spanned by the CNV. However, CNV boundaries are not known in advance, and the best way to proceed with this pooling is unclear. In this article, we propose a kernel-based method for aggregation of marker-level tests and explore several aspects of its implementation. In addition, we explore some of the theoretical aspects of marker-level test aggregation, proposing a permutation-based approach that preserves the family-wise error rate of the testing procedure, while demonstrating that several simpler alternatives fail to do so. The empirical power of the approach is studied in a number of simulations constructed from real data involving a pharmacogenomic study of gemcitabine, and compares favorably with several competing approaches

    Construction of isodual codes from polycirculant matrices

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    Double polycirculant codes are introduced here as a generalization of double circulant codes. When the matrix of the polyshift is a companion matrix of a trinomial, we show that such a code is isodual, hence formally self-dual. Numerical examples show that the codes constructed have optimal or quasi-optimal parameters amongst formally self-dual codes. Self-duality, the trivial case of isoduality, can only occur over \F_2 in the double circulant case. Building on an explicit infinite sequence of irreducible trinomials over \F_2, we show that binary double polycirculant codes are asymptotically good

    Full and half-wavelength ultrasonic percussive drills

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    Ultrasonic-percussive drills are a leading technology for small rock drilling applications where power and weight-on-bit are at a premium. The concept uses ultrasonic vibrations to excite an oscillatory motion in a free-mass, which then delivers impulsive blows to a drilling-bit. This is a relatively complex dynamic problem involving the transducer, the free-mass, the drilling-bit and, to a certain extent, the rock surface itself. This paper examines the performance of a full-wavelength transducer compared to a half-wavelength system, which may be more attractive due to mass and dimensional drivers. To compare the two approaches, three-dimensional finite element models of the ultrasonic-percussive stacks using full and half wavelength ultrasonic transducers are created to assess delivered impulse at similar power settings. In addition, impact-induced stress levels are evaluated to optimize the design of drill tools at a range of internal spring rates before, finally, experimental drilling is conducted. The results suggest that full-wavelength systems will yield much more effective impulse but, interestingly, their actual drilling performance was only marginally better than half-wavelength equivalents

    Design of a Solar Panel Deployment and Tracking System for Pocketqube Pico-Satellite

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    Modularized small satellites will have even greater potential with better energy supply. In this paper, a PocketQube solar panel deployment and tracking system will be presented. The system is designed for a 3P PocketQubes. During the designing phase, trade-off analysis is done to meet the balance of weight, dimension and efficiency. Reliability, manufacturability, and cost are also considered from the beginning, as commercial production and launch are expected. The CAD design, dynamics analysis, motion simulation, and rendering for the project are undertaken by Solidworks, whereas Abaqus CAE is utilized for the finite element analysis of the vibration test of the panels. In the gimbal subsystem, we use two micro stepper motor to drive the panels via a two-axis gearbox, enabling the panels to track the sun omnidirectionally. In the panel subsystem, two types of customized spring hinges are designed. Robust and verified parts, such as burner resistors, are chose for the control and deployment system. After the continuous optimization process throughout the design phase, by comparing different manufacturing processes technologies, materials, and design details, the full scale prototypes of the gimbal subsystem were built and tested. In the end, the most feasible solution, as well as the suggestions for the development, were put forward

    A father protocol for quantum broadcast channels

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    A new protocol for quantum broadcast channels based on the fully quantum Slepian-Wolf protocol is presented. The protocol yields an achievable rate region for entanglement-assisted transmission of quantum information through a quantum broadcast channel that can be considered the quantum analogue of Marton's region for classical broadcast channels. The protocol can be adapted to yield achievable rate regions for unassisted quantum communication and for entanglement-assisted classical communication; in the case of unassisted transmission, the region we obtain has no independent constraint on the sum rate, only on the individual transmission rates. Regularized versions of all three rate regions are provably optimal.Comment: Typo in statement of Theorem 4 fixe
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