209,413 research outputs found
Roberta M. Yee, December 16, 1924 - October 15, 2017
No full textMrs. Roberta M. Yee was a long time resident of Palo Alto, loving matriarch of the Yee family, and a pioneer
Humans Integrate Monetary and Liquid Incentives to Motivate Cognitive Task Performance (Yee et al., Frontiers in Cognition, 2016)
No full textAccompanying data and analyses for Yee et al. (2016) publication
Coded Modulation Assisted Radial Basis Function Aided Turbo Equalisation for Dispersive Rayleigh Fading Channels
No full textIn this contribution a range of Coded Modulation (CM) assisted Radial Basis Function (RBF) based Turbo Equalisation (TEQ) schemes are investigated when communicating over dispersive Rayleigh fading channels. Specifically, 16QAM based Trellis Coded Modulation (TCM), Turbo TCM (TTCM), Bit-Interleaved Coded Modulation (BICM) and iteratively decoded BICM (BICM-ID) are evaluated in the context of an RBF based TEQ scheme and a reduced-complexity RBF based In-phase/Quadrature-phase (I/Q) TEQ scheme. The Least Mean Square (LMS) algorithm was employed for channel estimation, where the initial estimation step-size used was 0.05, which was reduced to 0.01 for the second and the subsequent TEQ iterations. The achievable coding gain of the various CM schemes was significantly increased, when employing the proposed RBF-TEQ or RBF-I/Q-TEQ rather than the conventional non-iterative Decision Feedback Equaliser - (DFE). Explicitly, the reduced-complexity RBF-I/Q-TEQ-CM achieved a similar performance to the full-complexity RBF-TEQ-CM, while attaining a significant complexity reduction. The best overall performer was the RBF-I/Q-TEQ-TTCM scheme, requiring only 1.88~dB higher SNR at BER=10-5, than the identical throughput 3~BPS uncoded 8PSK scheme communicating over an AWGN channel. The coding gain of the scheme was 16.78-dB
A Wideband Radial Basis Function Decision Feedback Equaliser Assisted Burst-by-Burst Adaptive Modem
No full textThe performance of radial basis function-based decision feedback equalized (RBF DFE) burst-by-burst adaptive quadrature amplitude modulation (AQAM) is presented for transmissions over dispersive wide-band mobile channels. This scheme is shown to give a significant improvement in terms of the mean bit error rate (BER) and bits per symbol (BPS) performance compared to that of the individual fixed modulation modes. The structural equivalence of the RBF DFE to the optimal Bayesian equalizer enables it to potentially outperform the conventional Kalman-filtered AQAM DFE scheme. Index Terms—Adaptive modulation, decision feedback equalization, radial basis function, wide-band modem
Student Expectations in the New Millennium
No full textHigher education has experienced vast changes as a result of global political and economic developments. Cultural and social changes in the last decade have also added to the continuing evolution of higher education. These changes inevitably lead to changing expectations of students entering higher education. An adequate understanding of student expectations is crucial in ensuring a good fit between higher educational institutions and their students. This study attempts to carry out a baseline descriptive-quantitative research on student expectations in the higher education of Hong Kong. Four scales have been developed to measure students’ attitude toward: 1. job-oriented curriculum design, 2. user-friendly course delivery method, 3. opportunities for lifelong learning, and 4. student consumerism. Students’ priority of what makes a good university, their reasons for going to university, and their self-perception of ability to cope with university life are also explored. The Student Expectations Questionnaire (developed by the author) was used to gather data from 857 first-year undergrads from nine institutions of higher education in Hong Kong. Analyses include, among others, gender, age, major of study as well as institution comparisons
Nonmodular infinite products and a conjecture of Seo and Yee
No full textWe will tackle a conjecture of S. Seo and A. J. Yee, which says that the
series expansion of has nonnegative coefficients. Our
approach relies on an approximation of the generally nonmodular infinite
product , where is a positive integer and is any of
Habitats
No full textPredaceous diving beetles (Dytiscidae) are a highly speciose group of
insects occurring in a large variety of habitat types, where they typically form multispecies
assemblages, due to their high diversity and large variation in the degree of
habitat specifi city. This chapter provides an overview of the characteristics of the
main habitats where dytiscid species occur and summarizes the fi ndings of previous
studies aimed at characterizing the contribution of various abiotic habitat conditions
in determining patterns of dytiscid species distribution, including water fl ow,
permanency, salinity, acidity, temperature, and habitat size. Emphasis is given to the
description of various lentic and lotic habitats, and springs, along gradients of habitat
permanency. Given increasing evidence of the importance of biotic interactions
in determining the realized niche of many dytiscid species, this review describes
briefl y the role of predation, food sources, and inter- and intraspecifi c competition
as major habitat selection factors for certain dytiscid species. The signifi cance of the
structure of the vegetation as a major habitat factor determining patterns in dytiscid
species distribution is discussed and new insights on plant-dytiscid relationships are
provided. Some of the issues associated with developing simple habitat classifi cations
for dytiscid species are discussed. The main characteristics of some unique
habitats where dytiscids form unique assemblages, such as groundwater and interstitial
habitats, rock pools, hygropetric habitats, and phytotelmata are described
Entropy splitting for high-order numerical simulation of compressible turbulence
No full textA stable high-order numerical scheme for direct numerical simulation (DNS) of shock-free compressible turbulence is presented. The method is applicable to general geometries. It contains no upwinding, artificial dissipation, or filtering. Instead the method relies on the stabilizing mechanisms of an appropriate conditioning of the governing equations and the use of compatible spatial difference operators for the interior points (interior scheme) as well as the boundary points (boundary scheme). An entropy-splitting approach splits the inviscid flux derivatives into conservative and nonconservative portions. The spatial difference operators satisfy a summation-by-parts condition, leading to a stable scheme (combined interior and boundary schemes) for the initial boundary value problem using a generalized energy estimate. A Laplacian formulation of the viscous and heat conduction terms on the right hand side of the Navier–Stokes equations is used to ensure that any tendency to odd–even decoupling associated with central schemes can be countered by the fluid viscosity. The resulting methods are able to minimize the spurious high-frequency oscillations associated with pure central schemes, especially for long time integration applications such as DNS. For validation purposes, the methods are tested in a DNS of compressible turbulent plane channel flow at low values of friction Mach number, where reference turbulence data bases exist. It is demonstrated that the methods are robust in terms of grid resolution, and in good agreement with published channel data. Accurate turbulence statistics can be obtained with moderate grid sizes. Stability limits on the range of the splitting parameter are determined from numerical tests
Collocated electrodynamic FDTD schemes using overlapping Yee grids and higher-order Hodge duals
No full textAbstractThe collocated Lebedev grid has previously been proposed as an alternative to the Yee grid for electromagnetic finite-difference time-domain (FDTD) simulations. While it performs better in anisotropic media, it performs poorly in isotropic media because it is equivalent to four overlapping, uncoupled Yee grids. We propose to couple the four Yee grids and fix the Lebedev method using discrete exterior calculus (DEC) with higher-order Hodge duals. We find that higher-order Hodge duals do improve the performance of the Lebedev grid, but they also improve the Yee grid by a similar amount. The effectiveness of coupling overlapping Yee grids with a higher-order Hodge dual is thus questionable. However, the theoretical foundations developed to derive these methods may be of interest in other problems
Radial Basis Function Assisted Turbo Equalization
No full textThis paper presents a turbo equalization (TEQ) scheme, which employs a radial basis function (RBF)-based equalizer instead of the conventional trellis-based equalizer of Douillard et al. Structural, computational complexity, and performance comparisons of the RBF-based and trellis-based TEQs are provided. The decision feedback-assisted RBF TEQ is capable of attaining a similar performance to the logarithmic maximum scheme in the context of both binary phase-shift keying (BPSK) and quaternary phase-shift keying (QPSK) modulation, while achieving a factor 2.5 and 3 lower computational complexity, respectively. However, there is a 2.5-dB performance loss in the context of 16 quadrature amplitude modulation (QAM), which suffers more dramatically from the phenomenon of erroneous decision-feedback effects. A novel element of our design, in order to further reduce the computational complexity of the RBF TEQ, is that symbol equalizations are invoked at current iterations only if the decoded symbol has a high error probability. This techniques provides 37% and 54% computational complexity reduction compared to the full-complexity RBF TEQ for the BPSK RBF TEQ and 16QAM RBF TEQ, respectively, with little performance degradation, when communicating over dispersive Rayleigh fading channels. Index Terms—Decision-feedback equalizer (DFE), Jacobian logarithm, neural network, radial basis function (RBF), turbo coding, turbo equalization (TEQ)
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