160,359 research outputs found

    Tour-based Travel Mode Choice Estimation based on Data Mining and Fuzzy Techniques

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    This paper extends tour-based mode choice model, which mainly includes individual trip level interactions, to include linked travel modes of consecutive trips of an individual. Travel modes of consecutive trip made by an individual in a household have strong dependency or co-relation because individuals try to maintain their travel modes or use a few combinations of modes for current and subsequent trips. Traditionally, tour based mode choice models involved nested logit models derived from expert knowledge. There are limitations associated with this approach. Logit models assumes i) specific model structure (linear utility model) in advance; and, ii) it holds across an entire historical observations. These assumptions about the predefined model may be representative of reality, however these rules or heuristics for tour based mode choice should ideally be derived from the survey data rather than based on expert knowledge/ judgment. Therefore, in this paper, we propose a novel data-driven methodology to address the issues identified in tour based mode choice. The proposed methodology is tested using the Household Travel Survey (HTS) data of Sydney metropolitan area and its performances are compared with the state-of-the-art approaches in this area

    Exploiting correlogram structure for robust speech recognition with multiple speech sources

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    This paper addresses the problem of separating and recognising speech in a monaural acoustic mixture with the presence of competing speech sources. The proposed system treats sound source separation and speech recognition as tightly coupled processes. In the first stage sound source separation is performed in the correlogram domain. For periodic sounds, the correlogram exhibits symmetric tree-like structures whose stems are located on the delay that corresponds to multiple pitch periods. These pitch-related structures are exploited in the study to group spectral components at each time frame. Local pitch estimates are then computed for each spectral group and are used to form simultaneous pitch tracks for temporal integration. These processes segregate a spectral representation of the acoustic mixture into several time-frequency regions such that the energy in each region is likely to have originated from a single periodic sound source. The identified time-frequency regions, together with the spectral representation, are employed by a `speech fragment decoder' which employs `missing data' techniques with clean speech models to simultaneously search for the acoustic evidence that best matches model sequences. The paper presents evaluations based on artificially mixed simultaneous speech utterances. A coherence-measuring experiment is first reported which quantifies the consistency of the identified fragments with a single source. The system is then evaluated in a speech recognition task and compared to a conventional fragment generation approach. Results show that the proposed system produces more coherent fragments over different conditions, which results in significantly better recognition accuracy

    Numerical framework for transcritical real-fluid reacting flow simulations using the flamelet progress variable approach

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    An extension to the classical FPV model is developed for transcritical real-fluid combustion simulations in the context of finite volume, fully compressible, explicit solvers. A double-flux model is developed for transcritical flows to eliminate the spurious pressure oscillations. A hybrid scheme with entropy-stable flux correction is formulated to robustly represent large density ratios. The thermodynamics for ideal-gas values is modeled by a linearized specific heat ratio model. Parameters needed for the cubic EoS are pre-tabulated for the evaluation of departure functions and a quadratic expression is used to recover the attraction parameter. The novelty of the proposed approach lies in the ability to account for pressure and temperature variations from the baseline table. Cryogenic LOX/GH2 mixing and reacting cases are performed to demonstrate the capability of the proposed approach in multidimensional simulations. The proposed combustion model and numerical schemes are directly applicable for LES simulations of real applications under transcritical conditions.Comment: 55th AIAA Aerospace Sciences Meeting, Dallas, T

    A Study of Gluon Propagator on Coarse Lattice

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    We study gluon propagator in Landau gauge with lattice QCD, where we use an improved lattice action. The calculation of gluon propagator is performed on lattices with the lattice spacing from 0.40 fm to 0.24 fm and with the lattice volume from (2.40fm)4(2.40 fm)^4 to (4.0fm)4(4.0 fm)^4. We try to fit our results by two different ways, in the first one we interpret the calculated gluon propagators as a function of the continuum momentum, while in the second we interpret the propagators as a function of the lattice momentum. In the both we use models which are the same in continuum limit. A qualitative agreement between two fittings is found.Comment: Revtex 14pages, 11 figure

    A Descriptive Study of Male and Female Teachers' Preferences of Strategies Used for Teaching Speaking in SMPN 1 Singaraja,

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    Penelitian ini bertujuan untuk mendeskripsikan strategi yang dipilih oleh guru pria dan wanita dalam mengajar berbicara di SMPN 1 Singaraja. Penelitian ini menganalisis strategi yang dipilih oleh lima guru bahasa Inggris yang mengajar kelas tujuh dan delapan di SMPN 1 Singaraja. Penelitian ini dirancang sebagai sebuah penelitian deskriptif yang menerapkan teknik analisis isi (content analysis) untuk menunjukkan dan memverifikasi data yang diperlukan. Pengambilan data dilakukan dengan observasi, kuesioner, dan wawancara dengan guru pria dan wanita. Hasil penelitian ini menunjukkan bahwa guru pria dan wanita menggunakan empat dari tujuh strategi mengajar dalam mengajar berbicara pada siswa mereka. Strategi tersebut adalah instruksi langsung, diskusi, bekerja berkelompok, dan aktivitas kinerja. Alasan dari guru pria dan wanita menggunakan strategi tersebut karena strategi tersebut dapat membuat siswa aktif berpartisipasi di kelas. Siswa dapat bertukar pengetahuan, ide atau opini dalam diskusi atau bekerja berkelompok dengan siswa lainnya. Siswa juga dapat belajar berbicara lebih banyak dalam aktivitas kinerja yang dapat membuat siswa percaya diri ketika siswa harus berbicara dalam bahasa Inggris dengan orang lain. Kata Kunci : strategi mengajar, guru pria dan wanita, mengajar berbicara This study was carried out to describe male and female teachers' preferences of strategies used for teaching speaking and the reasons why male and female teachers used certain strategies for teaching speaking in SMPN 1 Singaraja. This study analyzed strategy preferences of five English teachers who taught in grade seven and eight in SMPN 1 Singaraja. This study was designed as a descriptive study by applying seven Killen's teaching strategies that adapted content analysis technique to reveal and verify the needed data. The data collection was done through observation, questionnaire, and interviewing male and female English teachers. The results show that male English teachers used four of seven Killen's teaching strategies in teaching speaking to their students. The strategies were direct instruction, discussion, group work, and performance activity. While female English teachers also preferred four of seven Killen's teaching strategies used for teaching speaking in the classroom. The reasons of male and female teachers used certain strategies because those strategies made students actively participate in the class. They could share their knowledge, ideas or opinion in discussion session or in group work with their partner or their group. They also learned to speak English more in the performance activity that could make them confident when they should speak English with other people

    Towards Laser Driven Hadron Cancer Radiotherapy: A Review of Progress

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    It has been known for about sixty years that proton and heavy ion therapy is a very powerful radiation procedure for treating tumours. It has an innate ability to irradiate tumours with greater doses and spatial selectivity compared with electron and photon therapy and hence is a tissue sparing procedure. For more than twenty years powerful lasers have generated high energy beams of protons and heavy ions and hence it has been frequently speculated that lasers could be used as an alternative to RF accelerators to produce the particle beams necessary for cancer therapy. The present paper reviews the progress made towards laser driven hadron cancer therapy and what has still to be accomplished to realise its inherent enormous potential.Comment: 40 pages, 24 figure

    Exploration of Resonant Continuum and Giant Resonance in the Relativistic Approach

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    Single-particle resonant-states in the continuum are determined by solving scattering states of the Dirac equation with proper asymptotic conditions in the relativistic mean field theory (RMF). The regular and irregular solutions of the Dirac equation at a large radius where the nuclear potentials vanish are relativistic Coulomb wave functions, which are calculated numerically. Energies, widths and wave functions of single-particle resonance states in the continuum for ^{120}Sn are studied in the RMF with the parameter set of NL3. The isoscalar giant octupole resonance of ^{120}Sn is investigated in a fully consistent relativistic random phase approximation. Comparing the results with including full continuum states and only those single-particle resonances we find that the contributions from those resonant-states dominate in the nuclear giant resonant processes.Comment: 16 pages, 2 figure

    Regolith production and transport at the Susquehanna Shale Hills Critical Zone Observatory, Part 2: Insights from meteoric 10Be

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    Regolith-mantled hillslopes are ubiquitous features of most temperate landscapes, and their morphology reflects the climatically, biologically, and tectonically mediated interplay between regolith production and downslope transport. Despite intensive research, few studies have quantified both of these mass fluxes in the same field site. Here we present an analysis of 87 meteoric 10Be measurements from regolith and bedrock within the Susquehanna Shale Hills Critical Zone Observatory (SSHO), in central Pennsylvania. Meteoric 10Be concentrations in bulk regolith samples (n=73) decrease with regolith depth. Comparison of hillslope meteoric 10Be inventories with analyses of rock chip samples (n=14) from a 24 m bedrock core confirms that >80% of the total inventory is retained in the regolith. The systematic downslope increase of meteoric 10Be inventories observed at SSHO is consistent with 10Be accumulation in slowly creeping regolith (∼ 0.2 cm yr-1). Regolith flux inferred from meteoric 10Be varies linearly with topographic gradient (determined from high-resolution light detection and ranging-based topography) along the upper portions of hillslopes at SSHO. However, regolith flux appears to depend on the product of gradient and regolith depth where regolith is thick, near the base of hillslopes. Meteoric 10Be inventories at the north and south ridgetops indicate minimum regolith residence times of 10.5 ± 3.7 and 9.1 ± 2.9 ky, respectively, similar to residence times inferred from U-series isotopes in Ma et al. (2013). The combination of our results with U-series-derived regolith production rates implies that regolith production and erosion rates are similar to within a factor of two on SSHO hillcrests. ©2013. American Geophysical Union. All Rights Reserved

    Coupled coarse graining and Markov Chain Monte Carlo for lattice systems

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    We propose an efficient Markov Chain Monte Carlo method for sampling equilibrium distributions for stochastic lattice models, capable of handling correctly long and short-range particle interactions. The proposed method is a Metropolis-type algorithm with the proposal probability transition matrix based on the coarse-grained approximating measures introduced in a series of works of M. Katsoulakis, A. Majda, D. Vlachos and P. Plechac, L. Rey-Bellet and D.Tsagkarogiannis,. We prove that the proposed algorithm reduces the computational cost due to energy differences and has comparable mixing properties with the classical microscopic Metropolis algorithm, controlled by the level of coarsening and reconstruction procedure. The properties and effectiveness of the algorithm are demonstrated with an exactly solvable example of a one dimensional Ising-type model, comparing efficiency of the single spin-flip Metropolis dynamics and the proposed coupled Metropolis algorithm.Comment: 20 pages, 4 figure
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