146 research outputs found
COMPLETE STREETS CODE FOR ROADWAY FACILITY IMPROVEMENT IN COLLEGE PARK CAMPUS, THE UNIVERSITY OF MARYLAND - A CONTEXT-SENSITIVE APPROACH
This design-research thesis suggests that the improvement of campus roadway facilities using Complete Streets principle and practices can enhance the overall pedestrian experience. Campus Drive, one of the main arterials in the College Park campus of the University of Maryland, will be used as a case study. Heavily used by a variety of users, often conflicting with one another, University of Maryland Campus Drive would benefit from a major planning and design amelioration to meet the increasing demands of serving as a university main street. The goal of this thesis project is to prioritize the benefits for pedestrians in the right-of-way and improve the pedestrian experience on campus. This goal also responds to the recent Facilities Master Plan vision of building a more walkable campus. The goal of this design-research thesis will be achieved focusing on four aspects. First, design and plans will discourage cut-through driving to reduce vehicular traffic volume on Campus Drive in order to reduce pedestrian and vehicle conflicts. Second, plans and designs will clarify cyclists' use of the right-of-way and create a built environment that will reduce and hopefully eliminate current riding on pedestrian sidewalk. Third, the case study seeks to improve public transit facilities on Campus Drive to better serve users of which the majorities travel as pedestrians on campus. Finally, the case study seeks to improve pedestrian facilities to enhance pedestrian connectivity, accessibility, and overall experience on University of Maryland Campus Drive.
Campus Drive roadway facilities will be inventoried. Roadway segments typologies will be identified and classified. A toolkit, road improvement design interventions, will be developed based on this classification. An improved master plan will be developed utilizing the toolkit while considering the specific site context around specific segments and the overall functions carried by Campus Drive as a campus main street. Detailed plans and designs will be developed for focus areas that demonstrate the goals and objectives.
The outcome of the design-research thesis project is expected to serve as an example of implementing Complete Streets principles and practices in urban commuter university campuses, where transportation needs and institutional functions interact with each other
Hybrid algorithms to solve linear systems of equations with limited qubit resources
The solution of linear systems of equations is a very frequent operation and
thus important in many fields. The complexity using classical methods increases
linearly with the size of equations. The HHL algorithm proposed by Harrow et
al. achieves exponential acceleration compared with the best classical
algorithm. However, it has a relatively high demand for qubit resources and the
solution is in a normalized form. Assuming that the
eigenvalues of the coefficient matrix of the linear systems of equations can be
represented perfectly by finite binary number strings, three hybrid iterative
phase estimation algorithms (HIPEA) are designed based on the iterative phase
estimation algorithm in this paper. The complexity is transferred to the
measurement operation in an iterative way, and thus the demand of qubit
resources is reduced in our hybrid algorithms. Moreover, the solution is stored
in a classical register instead of a quantum register, so the exact
unnormalized solution can be obtained. The required qubit resources in the
three HIPEA algorithms are different. HIPEA-1 only needs one single ancillary
qubit. The number of ancillary qubits in HIPEA-2 is equal to the number of
nondegenerate eigenvalues of the coefficient matrix of linear systems of
equations. HIPEA-3 is designed with a flexible number of ancillary qubits. The
HIPEA algorithms proposed in this paper broadens the application range of
quantum computation in solving linear systems of equations by avoiding the
problem that quantum programs may not be used to solve linear systems of
equations due to the lack of qubit resources.Comment: 22 pages, 6 figures, 6 tables, 48 equation
Hedgehog Spin-vortex Crystal Antiferromagnetic Quantum Criticality in CaK(Fe1-xNix)4As4 Revealed by NMR
Two ordering states, antiferromagnetism and nematicity, have been observed in
most iron-based superconductors (SCs). In contrast to those SCs, the newly
discovered SC CaK(FeNi)As exhibits an antiferromagnetic
(AFM) state, called hedgehog spin-vortex crystal structure, without nematic
order, providing the opportunity for the investigation into the relationship
between spin fluctuations and SC without any effects of nematic fluctuations.
Our As nuclear magnetic resonance studies on
CaK(FeNi)As (0 0.049) revealed that
CaKFeAs is located close to a hidden hedgehog SVC AFM quantum-critical
point (QCP). The magnetic QCP without nematicity in
CaK(FeNi)As highlights the close connection of spin
fluctuations and superconductivity in iron-based SCs. The advantage of
stoichiometric composition also makes CaKFeAs an ideal platform for
further detailed investigation of the relationship between magnetic QCP and
superconductivity in iron-based SCs without disorder effects.Comment: 6 pages, 5 figures, accepted for publication in Phys. Rev. Let
CURRENT DENSITY EFFECTS ON PLASMA EMISSION DURING PLASMA ELECTROLYTIC OXIDATION (PEO) ON AZ91D-MAGNESIUM ALLOY
The effect of bipolar pulse mode current ratio on plasma behavior was investigated in PEO on AZ91D Mg-Alloy. Two cases of current ratio including 1.20 and 0.88 were applied to the sample. Plasma emission behavior was studied using plasma images and plasma emission measured by photodetector and Intensified Charged-Couple Device (ICCD) camera. The current ratio of greater than 1 shows the continuous increase and then stabilization in emission intensity with a gradual increase in voltage throughout the PEO process. In contrast, the current ratio of less than 1, a sudden drop in plasma emission intensity with voltage was found after 786s. Therefore, PEO process can be divided into two regimes, arc regime and soft regime, before and after voltage drop respectively. Results of measured spectra show that a soft regime does not have atomic or ionic excitation during PEO process. It is demonstrated that the growth of porous layer during PEO can be controlled, which is benefit for the protective oxide coating of sample
Exploring Self-supervised Pre-trained ASR Models For Dysarthric and Elderly Speech Recognition
Automatic recognition of disordered and elderly speech remains a highly
challenging task to date due to the difficulty in collecting such data in large
quantities. This paper explores a series of approaches to integrate domain
adapted SSL pre-trained models into TDNN and Conformer ASR systems for
dysarthric and elderly speech recognition: a) input feature fusion between
standard acoustic frontends and domain adapted wav2vec2.0 speech
representations; b) frame-level joint decoding of TDNN systems separately
trained using standard acoustic features alone and with additional wav2vec2.0
features; and c) multi-pass decoding involving the TDNN/Conformer system
outputs to be rescored using domain adapted wav2vec2.0 models. In addition,
domain adapted wav2vec2.0 representations are utilized in
acoustic-to-articulatory (A2A) inversion to construct multi-modal dysarthric
and elderly speech recognition systems. Experiments conducted on the UASpeech
dysarthric and DementiaBank Pitt elderly speech corpora suggest TDNN and
Conformer ASR systems integrated domain adapted wav2vec2.0 models consistently
outperform the standalone wav2vec2.0 models by statistically significant WER
reductions of 8.22% and 3.43% absolute (26.71% and 15.88% relative) on the two
tasks respectively. The lowest published WERs of 22.56% (52.53% on very low
intelligibility, 39.09% on unseen words) and 18.17% are obtained on the
UASpeech test set of 16 dysarthric speakers, and the DementiaBank Pitt test set
respectively.Comment: accepted by ICASSP 202
Audio-visual End-to-end Multi-channel Speech Separation, Dereverberation and Recognition
Accurate recognition of cocktail party speech containing overlapping
speakers, noise and reverberation remains a highly challenging task to date.
Motivated by the invariance of visual modality to acoustic signal corruption,
an audio-visual multi-channel speech separation, dereverberation and
recognition approach featuring a full incorporation of visual information into
all system components is proposed in this paper. The efficacy of the video
input is consistently demonstrated in mask-based MVDR speech separation,
DNN-WPE or spectral mapping (SpecM) based speech dereverberation front-end and
Conformer ASR back-end. Audio-visual integrated front-end architectures
performing speech separation and dereverberation in a pipelined or joint
fashion via mask-based WPD are investigated. The error cost mismatch between
the speech enhancement front-end and ASR back-end components is minimized by
end-to-end jointly fine-tuning using either the ASR cost function alone, or its
interpolation with the speech enhancement loss. Experiments were conducted on
the mixture overlapped and reverberant speech data constructed using simulation
or replay of the Oxford LRS2 dataset. The proposed audio-visual multi-channel
speech separation, dereverberation and recognition systems consistently
outperformed the comparable audio-only baseline by 9.1% and 6.2% absolute
(41.7% and 36.0% relative) word error rate (WER) reductions. Consistent speech
enhancement improvements were also obtained on PESQ, STOI and SRMR scores.Comment: IEEE/ACM Transactions on Audio, Speech, and Language Processin
Confidence Score Based Speaker Adaptation of Conformer Speech Recognition Systems
Speaker adaptation techniques provide a powerful solution to customise
automatic speech recognition (ASR) systems for individual users. Practical
application of unsupervised model-based speaker adaptation techniques to data
intensive end-to-end ASR systems is hindered by the scarcity of speaker-level
data and performance sensitivity to transcription errors. To address these
issues, a set of compact and data efficient speaker-dependent (SD) parameter
representations are used to facilitate both speaker adaptive training and
test-time unsupervised speaker adaptation of state-of-the-art Conformer ASR
systems. The sensitivity to supervision quality is reduced using a confidence
score-based selection of the less erroneous subset of speaker-level adaptation
data. Two lightweight confidence score estimation modules are proposed to
produce more reliable confidence scores. The data sparsity issue, which is
exacerbated by data selection, is addressed by modelling the SD parameter
uncertainty using Bayesian learning. Experiments on the benchmark 300-hour
Switchboard and the 233-hour AMI datasets suggest that the proposed confidence
score-based adaptation schemes consistently outperformed the baseline
speaker-independent (SI) Conformer model and conventional non-Bayesian, point
estimate-based adaptation using no speaker data selection. Similar consistent
performance improvements were retained after external Transformer and LSTM
language model rescoring. In particular, on the 300-hour Switchboard corpus,
statistically significant WER reductions of 1.0%, 1.3%, and 1.4% absolute
(9.5%, 10.9%, and 11.3% relative) were obtained over the baseline SI Conformer
on the NIST Hub5'00, RT02, and RT03 evaluation sets respectively. Similar WER
reductions of 2.7% and 3.3% absolute (8.9% and 10.2% relative) were also
obtained on the AMI development and evaluation sets.Comment: IEEE/ACM Transactions on Audio, Speech, and Language Processin
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